Multiplexing functional polypeptides and recombinant rhabdoviral g glycoproteins on enveloped delivery vehicles

Abstract

In aspects, the present disclosure provides an enveloped delivery vehicle (EDV), comprising, consisting of, consisting essentially of: (1) an envelope membrane; (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same. In aspects, the present disclosure provides methods of generating EDVs described herein. In aspects, the present disclosure provides a method of improving the cell infection efficiency of an EDV as described herein. Additional aspects are as described herein.

Description

MULTIPLEXING FUNCTIONAL POLYPEPTIDES AND RECOMBINANT RHABDOVIRAL G GLYCOPROTEINS ON ENVELOPED DELIVERY VEHICLESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims the benefit U.S. Provisional Patent Application No. 63 / 660,355, filed June 14, 2024; U.S. Provisional Patent Application No. 63 / 660,217, filed June 14, 2024; and International Patent Application No. PCT / US2025 / 024301, filed April 11, 2025; the disclosures of which are incorporated herein by reference in their entireties for all purposes.INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ELECTRONICALLY

[0002] Incorporated by reference in its entirety herein is a computer-readable nucleotide / amino acid sequence listing submitted concurrently herewith and identified as follows: One 277,545 Byte XML (Extensible Markup Language) file named "773196_SequenceListing.xml," created on June 14, 2025.BACKGROUND

[0003] In vivo viral delivery is an increasingly important strategy for transporting nucleic acids, proteins, and small molecules directly into target cells. Enveloped viruses and other enveloped delivery vehicles (ED Vs) are widely used in therapeutic applications due to their ability to mediate membrane fusion and payload release. Precise targeting of such delivery systems improves therapeutic efficacy and limits off-target effects that can pose safety risks.

[0004] Rhabdoviral glycoproteins (G proteins) are among the tools employed to enable cellular entry in viral and EDV-based delivery platforms. These G proteins serve a dual function: they determine which cells are targeted and mediate the step of membrane fusion to deliver the payload. However, selecting or engineering the appropriate G protein to target a specific cell type remains a challenge. This is especially evident in applications like CAR-T, where it is important for viral vectors to selectively transduce T cells without affecting other populations. Similar challenges arise when targeting B cells, natural killer (NK) cells, macrophages, or progenitor populations such as hematopoietic stem cells (HSCs).

[0005] Accordingly, there remains an ongoing need for components that enable the selective targeting of enveloped viruses and EDVs to defined cell types. Receptor-blinded rhabdoviral G proteins — engineered to reduce or abolish binding to their natural receptors — fused to chimeric targeting molecules offer opportunities for retargeting to novel cellular entry points while still facilitating fusion with the target cell membrane. In particular, multiplexing receptor-blinded rhabdoviral G proteins fused with different targeting molecules could allow for more specific targeting of defined cell types. There is also a need for methods to develop such G proteins, or other functionally similar proteins, and for enveloped delivery vehicles that incorporate them to improve specificity and therapeutic performance. There is also an ongoing need in the art for viruses and enveloped delivery vehicles that incorporate such components.BRIEF SUMMARY

[0006] In aspects, the present disclosure provides an enveloped delivery vehicle (EDV), comprising, consisting of, consisting essentially of: (1) an envelope membrane; (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same.

[0007] In aspects, the present disclosure provides a method of generating an enveloped delivery vehicle (EDV), the method comprising, consisting of, consisting essentially of: (a) transfecting or transducing a host cell with at least one expression construct encoding at least two recombinant viral membrane glycoproteins (VMGs); wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same; (b) maintaining the host cell within suitable conditions for at least one first recombinant VMGand at least one second recombinant VMG encoded by at least one expression construct of (a) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (1) an envelope membrane; and (2) at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) that are incorporated into the envelope membrane; (I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a first targeting molecule; (II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; and wherein the first targeting molecule and the second targeting molecule are not the same.

[0008] In aspects, the present disclosure provides a method of generating an enveloped delivery vehicle (EDV), the method comprising, consisting of, consisting essentially of: (a) transfecting or transducing a host cell with: (i) at least one first expression construct encoding at least one first recombinant viral membrane glycoprotein (VMG); and (ii) at least one second expression construct encoding at least one second recombinant VMG; wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same; (b) maintaining the host cell within suitable conditions for at least one first recombinant VMG encoded by at least one first expression construct of (i) to be expressed and for at least one second recombinant VMG encoded by at least one second expression construct of (ii) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (1) an envelope membrane; (2) at least one first recombinant VMG encoded by at least one first expression construct of (i) that is incorporated into the envelope membrane; and (3) at least one second recombinant VMG encoded by at least one second expression construct of (ii) that is incorporated into the envelope membrane; (I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a first targeting molecule; and (II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising asubstantially intact FMG and (B) a second targeting molecule; and wherein the first targeting molecule and the second targeting molecule are not the same.

[0009] In aspects, the present disclosure provides a method of improving the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; the method comprising, consisting of, consisting essentially of designing or preparing the EDV to comprise at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same.

[0010] In aspects, the present disclosure provides an enveloped delivery vehicle (EDV) comprising, consisting of, consisting essentially of (1) an envelope membrane; (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; and (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; wherein the other recombinant fusion protein of (2) is not the same as the other recombinant fusion protein of (3); and wherein the EDV is produced using retrovirus infection.

[0011] In aspects, the present disclosure provides a method of generating an enveloped delivery vehicle (EDV), the method comprising: (a) transfecting or transducing a host cell with at least one expression construct encoding at least two recombinant viral membraneglycoproteins (VMGs); wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; (b) maintaining the host cell within suitable conditions for at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (1) an envelope membrane; and (2) at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) that are incorporated into the envelope membrane; (I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; (II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and (d) covalently bonding to at least one first recombinant VMG of (c) a polypeptide catcher within another recombinant fusion protein and covalently bonding to at least one second VMG of (c) a polypeptide catcher within another recombinant fusion protein, wherein the other recombinant fusion protein covalently bound to at least one first recombinant VMG of (c) is not the same as the otherrecombinant fusion protein covalently bound to at least one second recombinant VMG of (c); and wherein the EDV is produced using retrovirus infection.

[0012] In aspects, the present disclosure provides a method of generating an enveloped delivery vehicle (EDV), the method comprising, consisting of, consisting essentially of: (a) transfecting or transducing a host cell with: (i) at least one first expression construct encoding at least one first recombinant viral membrane glycoprotein (VMG); and (ii) at least one second expression construct encoding at least one second recombinant VMG; wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; (b) maintaining the host cell within suitable conditions for at least one first recombinant VMG encoded by at least one first expression construct of (i) to be expressed and for at least one second recombinant VMG encoded by at least one second expression construct of (ii) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (1) an envelope membrane; (2) at least one first recombinant VMG encoded by at least one first expression construct of (i) that is incorporated into the envelope membrane; and (3) at least one second recombinant VMG encoded by at least one second expression construct of (ii) that is incorporated into the envelope membrane; (I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; (II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and(B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and (d) covalently bonding to at least one first recombinant VMG of (c) a polypeptide catcher within another recombinant fusion protein and covalently bonding to at least one second VMG of (c) a polypeptide catcher within another recombinant fusion protein, wherein the other recombinant fusion protein covalently bound to at least one first recombinant VMG of (c) is not the same as the other recombinant fusion protein covalently bound to at least one second recombinant VMG of (c); and wherein the EDV is produced using retrovirus infection.

[0013] In aspects, the present disclosure provides a method of improving the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having (1) an envelope membrane and (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; and the method comprising, consisting of, consisting essentially of designing or preparing the EDV to comprise (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; wherein the other recombinant fusion protein of (2) is not the same as the other recombinant fusion protein of (3).

[0014] Additional aspects are as described herein.

[0015] Without wishing to be bound by any particular theory, there may be discussion herein of beliefs or understandings of underlying principles relating to the materials and methods disclosed herein. It is recognized that regardless of the ultimate correctness of anymechanistic explanation or hypothesis, an aspect of the disclosure can nonetheless be operative and useful.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of recombinant receptor blinded rhabdoviral G glycoproteins fused via a linker to various targeting molecules, such as a full-length ligand of stem cell factor (SCF) or thrombopoietin (TPO) or truncated peptide thereof and some of the trimer structures displaying two or more targeting molecules such recombinant proteins could form.

[0017] Figure 2 is an illustration summarizing how lentiviruses (LVs) pseudotyped with one or more recombinant rhabdoviral G glycoproteins fused with a targeting molecule were prepared and used to transduce cells.

[0018] Figures 3A-3D are images of western blots of lentivirus particles pseudotyped with one or more recombinant proteins of Vesiculovirus Indiana G glycoproteins (VSV-G) blinded to the low density lipoprotein receptor (LDL-R) by a deletion of the K47 residue (VSV-G-AK47) and fused via a linker molecule to a cKit receptor or thrombopoietin receptor (TPO-R), also known as myeloproliferative leukemia protein (cMpl), targeting molecule as shown in Table 1 below and showing staining of anti- VSV-G antibody, anti-SCF antibody, anti-TPO antibody and anti-p24 antibody. Figures 3 A-3B show the western blot for the virion pellet with short exposure times (FIG. 3A) and longer exposure times (FIG. 3B). Figures 3C- 3D show the western blot for the cell lysate with short exposure times (FIG. 3C) and longer exposure times (FIG. 3D).Table 1

[0019] Figures 4A-4D are a set of fluorescent micrographs of K562 parental cells (K562), K562 cells expressing the human thrombopoietin receptor (hTPO-R) which is also known as myeloproliferative leukemia protein (cMpl) (K562-hcMpl), K562 cells expressing humancKit (K562-hcKit), and K562 cells expressing both hcMpl and hcKit (K562-hcMpl-hcKit) transduced with lentivirus containing a GFP-expression cassette and pseudotyped with VSV- G according to Table 1. Figure 4A shows K562 and K562-hcMpl cells transduced with lentivirus particles pseudotyped with a recombinant protein of wild type VSV-G (VSV-G- WT), VSV-G-AK47 alone or displaying a human SCF ligand (hSCF) linked via a 19 amino acid linker (hSCF-19aaL(F)-VSV G-AK47), or a human TPO receptor targeting peptide with a (G)x8 and a (G)x5 spacer linked via a 19 amino acid linker (hTPO Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)- VS V G-AK47), or pseudotyped with a 1 :3 ratio of hSCF-19aaL(F)- VSV G-AK47 : VSV-G-AK47 or 1 :3 hTPO Romiplostim Gx8 w Gx5 spacer- 19aaL(F)- GAK47 : VSV-G-AK47. Figure 4B shows K562-hcKit and K562-hcMpl-hcKit cells transduced with lentivirus particles pseudotyped with the same recombinant VSV-G proteins as in Figure 4A. Figure 4C shows K562 and K562-hcMpl cells transduced with lentivirus particles pseudotyped with recombinant protein of hSCF-19aaL(F)-G-AK47 and Romiplostim Gx8 w Gx5-19aaL(F)-G-AK47 at a ratio of 1 : 1, 1 :2, 1 :3, 1 :4, 4: 1, 3: 1, or 2: 1. Figure 4D shows K562-hcKit and K562-hcMpl-hcKit cells transduced with lentivirus particles pseudotyped with the same recombinant VSV-G proteins as in Figure 4C.

[0020] Figure 5 is a schematic diagram showing recombinant receptor blinded rhabdoviral G glycoproteins fused via a linker to various TPO receptor targeting molecules, such as a truncated TPO peptide, Romiplostim, or AF 13948 (black, left), as well as SCF ligand (white, middle), and the various mixed trimer structures formed by different combinations of recombinant receptor blinded rhabdoviral G glycoproteins with (chimeric) or without (non-chimeric) a displayed targeting molecule.

[0021] Figures 6A-6B are images of western blots of lentivirus particles pseudotyped with one or more recombinant proteins of Vesiculovirus Indiana G glycoproteins (VSV-G) blinded to the low density lipoprotein receptor (LDL-R) by a deletion of the K47 residue (VSV-G-AK47) and fused via a linker molecule to a cKit receptor or TPO-R targeting molecule as shown in Table 2 below and showing staining of anti-VSV-G antibody, anti-SCF antibody, anti-TPO antibody and anti-p24 antibody. Figure 6A shows the western blot for the virion pellet. Figure 6B shows the western blot for the cell lysate.Table 2

[0022] Figures 7A-7B are a set of fluorescent micrographs of K562 parental cells (K562) and K562 cells expressing both hcMpl and hcKit (K562-hcMpl-hcKit) transduced with lentivirus containing a GFP-expression cassette and pseudotyped with VSV-G according to Table 2. Figure 7A shows K562 and K562-hcMpl-hcKit cells transduced with lentivirus particles pseudotyped with a recombinant protein of VSV-G-WT or VSV-G-AK47 alone or pseudotyped with a 1 :3 ratio of hSCF-19aaL(F)-VSV G-AK47 : VSV-G-AK47, hTPO aa21tol84-19aaL(F)-G-AK47 : VSV-G-AK47, AF13948 rev G4S linker no C-19aaL(F)-VSV G-AK47 : VSV-G-AK47, or hTPO Romiplostim Gx8 w Gx5 spacer- 19aaL(F)-GAK47 : VSV- G-AK47. Figure 7B shows K562 and K562-hcMpl-hcKit cells transduced with lentivirus particles pseudotyped with a ratio of 1 : 1 : 1 or 1 : 1 :6 (0.5:05:3) of hSCF-19aaL(F)-VSV G- AK47 : aa21tol84-19aaL(F)-GAK47 : VSV-G-AK47, hSCF-19aaL(F)-GAK47 : AF13948 rev G4S linker no C-19aaL(F)-GAK47 : VSV-G-AK47, or hSCF-19aaL(F)-GAK47 : Romiplostim Gx8 w Gx5 spacer- 19aaL(F)-GAK47 : VSV-G-AK47.

[0023] Figure 8 is a bar graph quantifying the percentage of GFP positive (GFP+) K562 parental and K562-hcMpl-hcKit cells shown in Figures 7A-7B.

[0024] Figures 9A-9F are a set of fluorescent micrographs of K562 parental cells (K562), K562 cells expressing hcMpl (K562-hcMpl), and K562 cells expressing hcKit (K562-hcKit) transduced with lentivirus containing a GFP-expression cassette and pseudotyped with a recombinant VSV-G according to Table 2. Figures 9A-9B show three replicates of the transduced K562 cells. Figures 9C-9D show three replicates of the transduced K562-hcKit cells. Figures 9E-9F show three replicates of the transduced K562-hcMpl cells.

[0025] Figure 10 is a bar graph quantifying the percentage of GFP+ K562 parental, K562-hcKit, and K562-hcMpl cells shown in Figures 9A-9F.

[0026] Figures 11 A-l 1C are a set of flow cytometry histograms showing intensity of GFP in the K562, K562-hcMpl, and K562-hcKit cells shown in Figures 9A-9F. Figure 11 A is a histogram of K562 negative control cells and the transduced K562 cells according to Table 2. Figure 1 IB is a histogram of K562-hcKit negative control cells and the transduced K562- hcKit cells according to Table 2. Figure 11C is a histogram of K562-hcMpl negative control cells and the transduced K562-hcMpl cells according to Table 2.

[0027] Figure 12 is an illustration summarizing how bone marrow derived human CD34 positive (hCD34+) cells were cultured under conditions with no cytokines (Condition 1) or conditions with cytokines (Condition 2) and then transduced with lentiviruses (LVs) containing a GFP-expression cassette (SEQ ID NO: 106) pseudotyped with recombinant rhabdoviral G glycoproteins fused with a cKit and / or TPO-R (also referred to as cMpl) targeting molecule.

[0028] Figures 13A-13F are fluorescent images showing the GFP positive cells in hCD34+ cells cultured without cytokines in Condition 1 (FIG. 13 A) or with cytokines added in Condition 2 (FIG. 13D) and flow cytometry dot plots showing the GFP positive cells as measured by intensity of GFP vs. FSC-A in hCD34+ cells cultured without cytokines in Condition 1 (FIGS. 13B-13C) or with cytokines added in Condition 2 (FIGS. 13E-13F) and transduced with a lentivirus containing a GFP cassette (SEQ ID NO: 106) and pseudotyped with VSV-G (VSV G-WT) (SEQ ID NO: 9); a recombinant protein of receptor blinded VSV- G with a triple substitution of K47Q+R354Q+Y209Q (VSV-G-QQQ) (SEQ ID NO: 14); a 1 :3, 1 :5, 1 :7, or 1 : 11 ratio mix of a recombinant fusion protein of hSCF (SEQ ID NO: 28) fused N terminal to VSV-G-QQQ (SEQ ID NO: 14) via a linker (19aaL(F)) (SEQ ID NO: 49) and VSV-G-QQQ (SEQ ID NO: 14) (1 :3, 1 :5, 1 :7, or 1 : 11 hSCF : G-QQQ); a 1 :3 ratio mixof a recombinant fusion protein of Romiplostim peptide (SEQ ID NO: 175) fused N terminal to VSV G QQQ (SEQ ID NO: 14) via a linker (19aaL(F)) (SEQ ID NO: 49) and VSV-G- QQQ (SEQ ID NO: 14) (1 :3 hTPO Rom. : G-QQQ); a 0.5:0.5:3 ratio mix of a recombinant fusion protein of hSCF (SEQ ID NO: 28) fused N terminal to VSV G QQQ (SEQ ID NO: 14) via a linker (19aaL(F)) (SEQ ID NO: 49), a recombinant fusion protein of Romiplostim peptide (SEQ ID NO: 175) fused N terminal to VSV G QQQ (SEQ ID NO: 14) via a linker (19aaL(F)) (SEQ ID NO: 49), and VSV-G-QQQ (SEQ ID NO: 14) (0.5:0 5:3 hSCF : hTPO Rom.: G-QQQ); or a 0.5:0.5:3 ratio mix of a recombinant fusion protein of hSCF (SEQ ID NO: 28) fused N terminal to VSV G QQQ (SEQ ID NO: 14) via a linker (19aaL(F)) (SEQ ID NO: 49), an empty plasmid control (pcDNA3.1), and VSV-G-QQQ (SEQ ID NO: 14) (0.5:0.5:3 hSCF:pcDNA3.1 :G-QQQ).

[0029] Figure 14 is a bar graph quantifying the percentage of GFP positive cells (% eGFP+ cells) in the hCD34+ cells cultured without cytokines in Condition 1 (FIGS. 13B- 13C) or with cytokines added in Condition 2 (FIGS. 13E-13F).

[0030] Figures 15A-15D are a set of flow cytometry histograms showing expression levels of receptors CD3, CD4, CD7, and CD8 in Jurkat and Sup-Tl cells. Figure 15A is a histogram of CD3 receptor levels in Jurkat and Sup-Tl cells. Figure 15B is a histogram of CD4 receptor levels in Jurkat and Sup-Tl cells. Figure 15C is a histogram of CD7 receptor levels in Jurkat and Sup-Tl cells. Figure 15D is a histogram of CD8 receptor levels in Jurkat and Sup-Tl cells.

[0031] Figure 16 is a schematic diagram of envelope plasmids encoding a recombinant protein of receptor blinded VSV-G with either a single deletion of K47 (VSV-G-AK47) or a triple substitution of K47Q+R354Q+Y209Q (VSV-G-QQQ) with a CD4 receptor targeting molecule linked N-terminal via an IgGl linker (IgGILink) and with an N-terminal VSV-G signaling peptide (SP).

[0032] Figures 17A-17B are images of western blots of lentivirus particles pseudotyped with one or more recombinant proteins of VSV-G-AK47 or VSV-G-QQQ displaying a CD4 receptor targeting single-chain variable fragment (scFv) or nanobody (NB) targeting molecule as shown in Table 3 and showing staining of anti -VSV-G antibody and anti-p24 antibody. Lentivirus particles pseudotyped with VSV-G-WT or a VSV-G-AK47 displaying the CD3 receptor targeting scFv UCHT1 were used as controls. Figure 17A shows the western blot for the cell lysate. Figure 17B shows the western blot for the virion pellet.Table 3

[0033] Figures 17C-17D are bar graphs quantifying the percentage of VSV-G that did not contain a targeting molecule (% Non-Chimeric VSV-G) and the percentage that did contain a targeting molecule (% Chimeric VSV-G) in the western blots shown in Figures 17A-17B. Figure 17C shows the bar graph for the cell lysate. Figure 17D shows the bar graph for the virion pellet.

[0034] Figures 18A-18F are a set of fluorescent micrographs of Jurkat, Sup-Tl, Nalm6, and K562 cells transduced with lentivirus containing a GFP-expression cassette and pseudotyped with recombinant VSV-G according to Table 3. Figure 18A shows Jurkat and Sup-Tl cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47, NB#10-G-AK47 : VSV-G-AK47, or NB#10- G-QQQ : VSV-G-QQQ. Figure 18B shows Jurkat and Sup-Tl cells transduced with a lentivirus pseudotyped a 1 :3 ratio of scFv#9- VSV-G-AK47 : VSV-G-AK47, scFv#9-VSV-G- QQQ: VSV-G-QQQ, NB#148-G-QQQ : VSV-G-QQQ, or scFv#73,74-VSV-G-QQQ: VSV- G-QQQ- Figure 18C shows Jurkat and Sup-Tl cells transduced with a lentivirus pseudotyped a 1 :3 ratio of scFv#175-VSV-G-QQQ : VSV-G-QQQ, scFv# 184- VSV-G-QQQ: VSV-G- QQQ, scFv# 192- VSV-G-QQQ: VSV-G-QQQ, or scFv#201 -VSV-G-QQQ: VSV-G-QQQ. Figure 18D shows Nalm6 and K562 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47, NB#10-G-AK47 : VSV-G-AK47, or NB#10-G-QQQ : VSV-G-QQQ. Figure 18E shows Nalm6 and K562 cells transduced with a lentivirus pseudotyped a 1 :3 ratio of scFv#9- VSV-G-AK47 : VSV-G-AK47, scFv#9- VSV-G-QQQ: VSV-G-QQQ, NB#148-G-QQQ : VSV-G-QQQ 8, or scFv#73,74-VSV-G-QQQ: VSV-G-QQQ. Figure 18F shows Nalm6 and K562 cells transduced with a lentivirus pseudotyped a 1 :3 ratio of scFv#175-VSV-G-QQQ : VSV-G- QQQ, scFv# 184- VSV-G-QQQ: VSV-G-QQQ, scFv# 192- VSV-G-QQQ: VSV-G-QQQ, or scFv#201 -VSV-G-QQQ: VSV-G-QQQ.

[0035] Figures 19A-19F are a set of fluorescent micrographs of Jurkat, Sup-Tl, Nalm6, and K562 cells transduced with lentivirus containing a GFP-expression cassette and pseudotyped with recombinant VSV-G according to Table 3. Figure 19A shows two replicates of Jurkat and Sup-Tl cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47, or NB#10-G- QQQ : VSV-G-QQQ, or scFv#9-VSV-G-AK47 : VSV-G-AK47. Figure 19B shows two replicates of Jurkat and Sup-Tl cells transduced with a lentivirus pseudotyped a 1 :3 ratio of scFv#9- VSV-G-AK47 : VSV-G-AK47, NB#148-G-QQQ : VSV-G-QQQ, or scFv#73,74- VSV-G-QQQ: VSV-G-QQQ, or scFv#175-VSV-G-QQQ: VSV-G-QQQ,. Figure 19C shows two replicates of Jurkat and Sup-Tl cells transduced with a lentivirus pseudotyped a 1 :3 ratio of scFv# 184- VSV-G-QQQ: VSV-G-QQQ, scFv# 192- VSV-G-QQQ: VSV-G-QQQ, or scFv#201 -VSV-G-QQQ: VSV-G-QQQ or UCHT1 -VSV-G- AK47 : VSV-G- AK47. Figure 19D shows two replicates of Nalm6 and K562 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47, or NB#10- G-QQQ : VSV-G-QQQ, or scFv#9-VSV-G-AK47 : VSV-G-AK47. Figure 19E shows two replicates of Nalm6 and K562 cells transduced with a lentivirus pseudotyped a 1 :3 ratio of scFv#9- VSV-G-QQQ: VSV-G-QQQ, NB#148-G-QQQ : VSV-G-QQQ, or scFv#73, 74- VSV- G-QQQ: VSV-G-QQQ, or scFv#175-VSV-G-QQQ: VSV-G-QQQ. Figure 19F shows two replicates of Nalm6 and K562 cells transduced with a lentivirus pseudotyped a 1 :3 ratio of scFv# 184- VSV-G-QQQ: VSV-G-QQQ, scFv# 192- VSV-G-QQQ: VSV-G-QQQ, or scFv#201 -VSV-G-QQQ: VSV-G-QQQ, or UCHT1- VSV-G- AK47 : VSV-G-AK47.

[0036] Figure 20 is a bar graph quantifying the number of GFP+ Jurkat, Sup-Tl, Nalm6 and K562 cells shown in Figures 19A-19F.

[0037] Figures 21A-21B are images of western blots of lentivirus particles pseudotyped with a 1 :3 ratio of NB10-VSV-G-AK47 : VSV-G-AK47 or scFv9-VSV-G-AK47 : VSV-G- AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G- AK47 : NB10-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv9-VSV-G-AK47 : VSV-G-AK47 as shown in Table 4 and showing staining of anti-VSV-G antibody and anti-p24 antibody. Lentivirus particles pseudotyped with VSV-G-WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV- G-AK47 were used as controls. Figure 21 A shows the western blot for the cell lysate. Figure 2 IB shows the western blot for the virion pellet.Table 4

[0038] Figures 21C-21D are bar graphs quantifying the percentage of VSV-G that did not contain a targeting molecule (% Non-Chimeric VSV-G) and the percentage that did contain a targeting molecule (% Chimeric VSV-G) in the western blots shown in Figures 21 A-21B. Figure 21C shows the bar graph for the cell lysate. Figure 2 ID shows the bar graph for the virion pellet.

[0039] Figures 22A-22F are a set of fluorescent micrographs of Jurkat cells, Jurkat cells with the LDL-R knocked out (Jurkat LDLR KO), Jurkat cells with the T-cell receptor (TCR) knocked out (Jurkat TCR KO), Sup-Tl cells, and Nalm6 cells transduced with lentivirus containing a GFP-expression cassette and pseudotyped with recombinant VSV-G according to Table 4 either with or without a spin step. Figure 22A shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G- WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47 and no spin. Figure 22B shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47 or scFv#9- VSV- G-AK47 : VSV-G-AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G- AK47 : NB10-VSV- G-AK47 : VSV-G-AK47 or UCHT1- VSV-G- AK47 : scFv9-VSV-G-AK47 : VSV-G-AK47and no spin. Figure 22C shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1-VSV-G- AK47 : VSV-G-AK47 and no spin. Figure 22D shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47 or scFv#9- VSV-G-AK47 : VSV-G-AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB10- VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv9-VSV-G-AK47 : VSV-G- AK47 and no spin. Figure 22E shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 and spin. Figure 22F shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47 or scFv#9- VSV-G-AK47 : VSV-G-AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB10-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv9-VSV-G-AK47 : VSV-G-AK47 and spin. Figure 22G shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G- WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 and spin. Figure 22H shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47 or scFv#9- VSV-G-AK47 : VSV-G-AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB10-VSV-G-AK47 : VSV-G-AK47 or UCHT1- VSV-G-AK47 : scFv9-VSV-G-AK47 : VSV-G-AK47 and spin.

[0040] Figures 23 A-23F are a set of fluorescent micrographs of Jurkat cells, Jurkat cells with the LDL-R knocked out (Jurkat LDLR KO), Jurkat cells with the T-cell receptor (TCR) knocked out (Jurkat TCR KO), Sup-Tl cells, and Nalm6 cells transduced with lentivirus containing a GFP-expression cassette and pseudotyped with recombinant VSV-G according to Table 4 either with or without a spin step. Figure 23 A shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G- WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47 and no spin. Figure 23B shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47 or scFv#9- VSV- G-AK47 : VSV-G-AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G- AK47 : NB10-VSV- G-AK47 : VSV-G-AK47 or UCHT1- VSV-G- AK47 : scFv9-VSV-G-AK47 : VSV-G-AK47 and no spin. Figure 23C shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1-VSV-G- AK47 : VSV-G-AK47 and no spin. Figure 23D shows Sup-Tl and Nalm6 cells transducedwith a lentivirus pseudotyped with a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47 or scFv#9- VSV-G-AK47 : VSV-G-AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB10- VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv9-VSV-G-AK47 : VSV-G- AK47 and no spin. Figure 23E shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 and spin. Figure 23F shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47 or scFv#9- VSV-G-AK47 : VSV-G-AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB10-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv9-VSV-G-AK47 : VSV-G-AK47 and spin. Figure 23 G shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G- WT, VSV-G-AK47, or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 and spin. Figure 23H shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with a 1 :3 ratio of NB#10-G-AK47 : VSV-G-AK47 or scFv#9- VSV-G-AK47 : VSV-G-AK47, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB10-VSV-G-AK47 : VSV-G-AK47 or UCHT1- VSV-G-AK47 : scFv9-VSV-G-AK47 : VSV-G-AK47 and spin.

[0041] Figures 24A-24B are bar graphs quantifying the number of GFP+ Jurkat, Jurkat LDLR KO, Jurkat TCR KO, Sup-Tl, and Nalm6 cells shown in Figures 23 A-23H. Figure 24A is a bar graph of the cells transduced with no spin. Figure 24B is a is a bar graph of the cells transduced with spin.

[0042] Figures 25A-25B are bar graphs quantifying the fold change in the number of GFP+ Sup-Tl, Jurkat TCR-KO, Jurkat, and Nalm6 cells transduced with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB10-VSV-G-AK47 : VSV-G-AK47 (Dual-1) or UCHT1- VSV-G-AK47 : scFv9-VSV-G-AK47 : VSV-G-AK47 (Dual-2) over the same cells transduced with a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 (aCD3), NB#10-G-AK47 : VSV-G- AK47 (aCD4-l), or scFv#9- VSV-G-AK47 : VSV-G-AK47 (aCD4-2) shown in Figures 23 A- 23H. Figure 25A is a bar graph of the cells transduced with no spin. Figure 25B is a is a bar graph of the cells transduced with spin.

[0043] Figure 26 is a schematic diagram of envelope plasmids encoding a recombinant protein of receptor blinded VSV-G with either a single deletion of K47 (VSV-G-AK47) or a triple substitution of K47Q+R354Q+Y209Q (VSV-G-QQQ) with a CD8 receptor targeting molecule linked N-terminal via an IgGl linker (IgGILink) and with an N-terminal VSV-G signaling peptide (SP).

[0044] Figures 27A-27B are images of western blots of lentivirus particles pseudotyped with one or more recombinant proteins of VSV-G-AK47 or VSV-G-QQQ displaying a CD8 receptor targeting minibody, nanobody, or scFv targeting molecule as shown in Table 5 and showing staining of anti-VSV-G antibody and anti-p24 antibody. Lentivirus particles pseudotyped with VSV-G-WT or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 were used as controls. Figure 27A shows the western blot for the cell lysate. Figure 27B shows the western blot for the virion pellet.Table 5

[0045] Figures 27C-27D are bar graphs quantifying the percentage of VSV-G that did not contain a targeting molecule (% Non-Chimeric VSV-G) and the percentage that did contain a targeting molecule (% Chimeric VSV-G) in the western blots shown in Figures 27A-27B.Figure 27C shows the bar graph for the cell lysate. Figure 27D shows the bar graph for the virion pellet.

[0046] Figures 28A-28L are a set of fluorescent micrographs of Jurkat, Jurkat LDLR KO, Jurkat TCR KO, Sup-Tl, and Nalm6 cells transduced with lentivirus containing a GFP- expression cassette and pseudotyped with recombinant VSV-G according to Table 5. Figure 28A shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G- AK47,minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28-G-AK47 : VSV-G-AK47 with no spin. Figure 28B shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of NB#28-G-QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV-G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G-QQQ, scFv(TRX2)#98-G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with no spin. Figure 28C shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of scFv#48-G-QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G-QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51-G-QQQ : VSV- G-QQQ, or scFv#114,115-G-QQQ : VSV-G-QQQ, with no spin. Figure 28D shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28-G-AK47 : VSV-G-AK47 with no spin. Figure 28E shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of NB#28-G-QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV-G- QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G-QQQ, scFv(TRX2)#98-G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with no spin. Figure 28F shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of scFv#48-G-QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G- QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51-G-QQQ : VSV-G-QQQ, or scFv#114,115- G-QQQ : VSV-G-QQQ, with no spin. Figure 28G shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28-G-AK47 : VSV-G-AK47 with spin. Figure 28H shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of NB#28-G-QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV-G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G-QQQ, scFv(TRX2)#98- G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with spin. Figure 281 shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of scFv#48-G- QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G-QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51-G-QQQ : VSV-G-QQQ, or scFv#114,115-G-QQQ : VSV-G-QQQ, with spin. Figure 28J shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28-G-AK47 : VSV-G-AK47 with spin. Figure 28K shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of NB#28-G-QQQ : VSV-G- QQQ, NB#47-G-QQQ : VSV-G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G-QQQ, scFv(TRX2)#98-G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with spin. Figure 28L shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of scFv#48-G-QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G-QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51- G-QQQ : VSV-G-QQQ, or scFv#114,115-G-QQQ : VSV-G-QQQ, with spin.

[0047] Figures 29A-29L are a set of fluorescent micrographs of Jurkat, Jurkat LDLR KO, Jurkat TCR KO, Sup-Tl, and Nalm6 cells transduced with lentivirus containing a GFP- expression cassette and pseudotyped with recombinant VSV-G according to Table 5. Figure 29A shows two replicates of Jurkat cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28-G-AK47 : VSV-G-AK47 with no spin. Figure 29B shows two replicates of Jurkat cells transduced with a 1 :3 ratio of NB#28-G- QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV-G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G- QQQ, scFv(TRX2)#98-G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with no spin. Figure 29C shows two replicates of Jurkat cells transduced with a 1 :3 ratio of scFv#48-G-QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G-QQQ, scFv#50-G-QQQ : VSV- G-QQQ, scFv#51-G-QQQ : VSV-G-QQQ, or scFv#114,115-G-QQQ : VSV-G-QQQ, with no spin. Figure 29D shows two replicates of Jurkat LDLR KO and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28- G-AK47 : VSV-G-AK47 with no spin. Figure 29E shows two replicates of Jurkat LDLR KO and Jurkat TCR KO cells transduced with a 1 :3 ratio of NB#28-G-QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV-G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G-QQQ, scFv(TRX2)#98- G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with no spin. Figure 29F shows two replicates of Jurkat LDLR KO and Jurkat TCR KO cells transduced with a 1 :3 ratio of scFv#48-G-QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G-QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51-G-QQQ : VSV-G-QQQ, or scFv#114,115-G-QQQ : VSV-G-QQQ, with no spin. Figure 29G shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G- AK47, minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28-G-AK47 : VSV-G-AK47 with no spin. Figure 29H shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of NB#28-G-QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV-G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G- QQQ, scFv(TRX2)#98-G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with no spin. Figure 291 shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of scFv#48-G- QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G-QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51-G-QQQ : VSV-G-QQQ, or scFv#114,115-G-QQQ : VSV-G-QQQ, with no spin.

[0048] Figure 29J shows two replicates of Jurkat cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G- AK47, minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28-G-AK47 : VSV-G-AK47 with spin. Figure 29K shows two replicates of Jurkat cells transduced with a 1 :3 ratio of NB#28- G-QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV-G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G- QQQ, scFv(TRX2)#98-G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with spin. Figure 29L shows two replicates of Jurkat cells transduced with a 1 :3 ratio of scFv#48- G-QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G-QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51-G-QQQ : VSV-G-QQQ, or scFv#114,115-G-QQQ : VSV-G-QQQ, with spin. Figure 29M shows two replicates of Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV-G-QQQ, or NB#28-G-AK47 : VSV-G- AK47 with spin. Figure 29N shows two replicates of Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of NB#28-G-QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV- G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G-QQQ, scFv(TRX2)#98-G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with spin. Figure 290 shows two replicates of Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of scFv#48-G-QQQ : VSV- G-QQQ, scFv#49-G-QQQ : VSV-G-QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51-G- QQQ : VSV-G-QQQ, or scFv#114,115-G-QQQ : VSV-G-QQQ, with spin. Figure 29P shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G- WT or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV- G-QQQ, or NB#28-G-AK47 : VSV-G-AK47 with spin. Figure 29Q shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of NB#28-G-QQQ : VSV-G-QQQ, NB#47-G-QQQ : VSV- G-QQQ, scFv(OKT8)#8,9-G-QQQ : VSV-G-QQQ, scFv(TRX2)#98-G-QQQ : VSV-G-QQQ, or scFv#48-G-AK47 : VSV-G-AK47, with spin. Figure 29R shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of scFv#48-G-QQQ : VSV-G-QQQ, scFv#49-G-QQQ : VSV-G- QQQ, scFv#50-G-QQQ : VSV-G-QQQ, scFv#51-G-QQQ : VSV-G-QQQ, or scFv#114,115- G-QQQ : VSV-G-QQQ, with spin.

[0049] Figures 30A-30B are bar graphs quantifying the number of GFP+ Jurkat, Jurkat LDLR-KO, Jurkat TCR KO, Sup-Tl, and Nalm6 cells shown in Figures 29A-29R. Figure 30A is a bar graph of the cells transduced with no spin. Figure 30B is a is a bar graph of the cells transduced with spin.

[0050] Figures 31 A- 3 IB are images of western blots of lentivirus particles pseudotyped with a 1 :3 ratio of NB#28-VSV-G-AK47 : VSV-G-AK47, scFv#48-VSV-G-AK47 : VSV-G- AK47, or scFv#48-VSV-G-QQQ : VSV-G-QQQ, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV- G-AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48-VSV-G- AK47 : VSV-G-AK47, or UCHT1 -VSV-G-QQQ : scFv#48- VSV-G-QQQ : VSV-G-QQQ, as shown in Table 6 and showing staining of anti-VSV-G antibody and anti-p24 antibody.Lentivirus particles pseudotyped with VSV-G-WT, VSV-G-AK47, VSV-G-QQQ, or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV- G-AK47 or UCHT1- VSV-G-QQQ : VSV- G-QQQ were used as controls. Figure 31 A shows the western blot for the cell lysate. Figure 3 IB shows the western blot for the virion pellet.Table 6

[0051] Figures 32A-32L are a set of fluorescent micrographs of Jurkat, Jurkat LDLR KO, Jurkat TCR KO, Sup-Tl, and Nalm6 cells transduced with lentivirus containing a GFP- expression cassette and pseudotyped with recombinant VSV-G according to Table 6.

[0052] Figure 32A shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, VSV-G-QQQ or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47 with no spin. Figure 32B shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of UCHT1- VSV-G- QQQ : VSV-G-QQQ, NB#28-G-AK47 : VSV-G-AK47, scFv#48-G-AK47 : VSV-G-AK47, scFv#48-G- VSV-G-QQQ : VSV-G-QQQ with no spin. Figure 32C shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G-AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48- VSV-G-AK47 : VSV-G-AK47, Or UCHT1- VSV-G-QQQ : scFv#48-VSV-G-QQQ : VSV-G- QQQ with no spin. Figure 32D shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, VSV-G-QQQ or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 with no spin. Figure 32E shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of UCHT1- VSV-G-QQQ : VSV-G-QQQ, NB#28-G-AK47 : VSV-G-AK47, scFv#48-G-AK47 : VSV-G-AK47, scFv#48-G-VSV-G-QQQ : VSV-G-QQQ with no spin. Figure 32F shows Sup-Tl and Nalm6 cells transduced with 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G- AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G- AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, or UCHT1- VSV-G-QQQ : scFv#48-VSV-G- QQQ : VSV-G-QQQ with no spin.

[0053] Figure 32G shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, VSV-G-QQQ or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV-G- QQQ, or NB#28-G-AK47 : VSV-G-AK47 with spin. Figure 32H shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of UCHT1- VSV-G-QQQ : VSV-G- QQQ, NB#28-G-AK47 : VSV-G-AK47, scFv#48-G-AK47 : VSV-G-AK47, or scFv#48-G- VSV-G-QQQ : VSV-G-QQQ with spin. Figure 321 shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, Or UCHT1- VSV-G-QQQ : scFv#48-VSV-G-QQQ : VSV-G-QQQ with spin. Figure 32J shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, VSV-G-QQQ or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 with spin. Figure 32K shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of UCHT1-VSV-G-QQQ : VSV-G-QQQ, NB#28-G-AK47 : VSV-G-AK47, scFv#48-G-AK47 : VSV-G-AK47, or scFv#48-G-VSV-G-QQQ : VSV-G-QQQ with spin. Figure 32L shows Sup-Tl and Nalm6 cells transduced with a 1 :1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, or UCHT1- VSV-G-QQQ : scFv#48-VSV-G-QQQ : VSV-G-QQQ with spin.

[0054] Figures 33 A-33L are a set of fluorescent micrographs of Jurkat, Jurkat LDLR KO,Jurkat TCR KO, Sup-Tl, and Nalm6 cells transduced with lentivirus containing a GFP- expression cassette and pseudotyped with recombinant VSV-G according to Table 6.

[0055] Figure 33 A shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, VSV-G-QQQ or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47 with no spin. Figure 33B shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of UCHT1- VSV-G- QQQ : VSV-G-QQQ, NB#28-G-AK47 : VSV-G-AK47, scFv#48-G-AK47 : VSV-G-AK47, scFv#48-G- VSV-G-QQQ : VSV-G-QQQ with no spin. Figure 33C shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G-AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48- VSV-G-AK47 : VSV-G-AK47, or UCHT1- VSV-G-QQQ : scFv#48-VSV-G-QQQ : VSV-G- QQQ with no spin. Figure 33D shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, VSV-G-QQQ or a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 with no spin. Figure 33E shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of UCHT1- VSV-G-QQQ : VSV-G-QQQ, NB#28-G-AK47 : VSV-G-AK47, scFv#48-G-AK47 : VSV-G-AK47, scFv#48-G-VSV-G-QQQ : VSV-G-QQQ with no spin. Figure 33F shows Sup-Tl and Nalm6 cells transduced with 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G- AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G- AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, or UCHT1- VSV-G-QQQ : scFv#48-VSV-G- QQQ : VSV-G-QQQ with no spin.

[0056] Figure 33G shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, VSV-G-QQQ or a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47, minibody#36,37-G-QQQ : VSV-G- QQQ, or NB#28-G-AK47 : VSV-G-AK47 with spin. Figure 33H shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :3 ratio of UCHT1- VSV-G-QQQ : VSV-G-QQQ, NB#28-G-AK47 : VSV-G-AK47, scFv#48-G-AK47 : VSV-G-AK47, or scFv#48-G- VSV-G-QQQ : VSV-G-QQQ with spin. Figure 331 shows Jurkat, Jurkat LDLR KO, and Jurkat TCR KO cells transduced with a 1 :1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, or UCHT1- VSV-G-QQQ : scFv#48-VSV-G-QQQ : VSV-G-QQQ with spin. Figure 33J shows Sup-Tl and Nalm6 cells transduced with a lentivirus pseudotyped with recombinant VSV-G-WT, VSV-G-AK47, VSV-G-QQQ or a 1 :3 ratio of UCHT1-VSV-G- AK47 : VSV-G-AK47 with spin. Figure 33K shows Sup-Tl and Nalm6 cells transduced with a 1 :3 ratio of UCHT1- VSV-G-QQQ : VSV-G-QQQ, NB#28-G-AK47 : VSV-G-AK47, scFv#48-G-AK47 : VSV-G-AK47, or scFv#48-G-VSV-G-QQQ : VSV-G-QQQ with spin. Figure 33L shows Sup-Tl and Nalm6 cells transduced with a 1 :1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, Or UCHT1- VSV-G-QQQ : scFv#48-VSV-G-QQQ : VSV-G-QQQ with spin.

[0057] Figures 34A-34B are bar graphs quantifying the number of GFP+ Jurkat, Jurkat LDLR-KO, Jurkat TCR KO, Sup-Tl, and Nalm6 cells shown in Figures 33A-33L. Figure 34A is a bar graph of the cells transduced with no spin. Figure 34B is a is a bar graph of the cells transduced with spin.

[0058] Figures 34C-34D are bar graphs quantifying the fold change in the number of GFP+ Sup-Tl, Jurkat TCR-KO, Jurkat, and Nalm6 and K562 cells transduced with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV-G-AK47 (Dual-1) or UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47 (Dual-2) over the same cells transduced with a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 (aCD3), NB#28- G-AK47 : VSV-G-AK47 (aCD8-l), or scFv#48- VSV-G-AK47 : VSV-G-AK47 (aCD8-2) shown in Figures 33A-33L. Figure 34C is a bar graph of the cells transduced with no spin. Figure 34D is a is a bar graph of the cells transduced with spin.

[0059] Figures 35A-35H are a set of flow cytometry dot plots showing flow scatter area (FSC-A) vs. LD780, CD8 vs. CD4, GFP vs CD3, GFP vs CD4, and GFP vs CD8 for human peripheral blood mononuclear cells (PBMCs) given a mock treatment or transduced with lentivirus particles pseudotyped with a recombinant VSV-G-WT or a 1 :3 ratio of UCHT1- VSV-G-AK47 : VSV-G-AK47, UCHT1 -VSV-G-QQQ : VSV-G-QQQ, NB#28-VSV-G-AK47 : VSV-G-AK47, scFv#48-VSV-G-AK47 : VSV-G-AK47, or scFv#48-VSV-G-QQQ : VSV-G- QQQ, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G- QQQ : scFv#48-VSV-G-QQQ : VSV-G-QQQ, as shown in Table 6. Figure 35A is a set of a flow cytometry dot plots showing FSC-A vs. LD780 and CD8 vs. CD4 for PBMCs given the mock treatment or transduced with lentivirus particles pseudotyped with recombinant VSV- G-WT. Figure 35B is a set of a flow cytometry dot plots showing GFP vs CD3, GFP vs CD4, and GFP vs CD8 for PBMCs given the mock treatment or transduced with lentivirus particles pseudotyped with recombinant VSV-G-WT. Figure 35C is a set of a flow cytometry dot plots showing FSC-A vs. LD780 and CD8 vs. CD4 for PBMCs transduced with lentivirus particles pseudotyped with a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 or UCHT1- VSV-G- QQQ : VSV-G-QQQ. Figure 35D is a set of a flow cytometry dot plots showing GFP vs CD3, GFP vs CD4, and GFP vs CD8 for PBMCs transduced with lentivirus particles pseudotyped with a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 or UCHT1- VSV-G-QQQ : VSV-G- QQQ. Figure 35E is a set of a flow cytometry dot plots showing FSC-A vs. LD780 and CD8 vs. CD4 for PBMCs transduced with lentivirus particles pseudotyped with a 1 :3 ratio of NB#28-VSV-G-AK47 : VSV-G-AK47, scFv#48-VSV-G-AK47 : VSV-G-AK47, or scFv#48- VSV-G-QQQ : VSV-G-QQQ. Figure 35F is a set of a flow cytometry dot plots showing GFP vs CD3, GFP vs CD4, and GFP vs CD8 for PBMCs transduced with lentivirus particles pseudotyped with a 1 :3 ratio of NB#28-VSV-G-AK47 : VSV-G-AK47, scFv#48-VSV-G- AK47 : VSV-G-AK47, or scFv#48-VSV-G-QQQ : VSV-G-QQQ. Figure 35G is a set of a flow cytometry dot plots showing FSC-A vs. LD780 and CD8 vs. CD4 for PBMCs transduced with lentivirus particles pseudotyped with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48- VSV-G-AK47 : VSV-G-AK47, UCHT1 -VSV-G-QQQ : scFv#48-VSV-G-QQQ : VSV-G- QQQ. Figure 35H is a set of a flow cytometry dot plots showing GFP vs CD3, GFP vs CD4, and GFP vs CD8 for PBMCs transduced with lentivirus particles pseudotyped with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV-G-AK47, UCHT1- VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, UCHT1 -VSV-G-QQQ : scFv#48- VSV-G-QQQ : VSV-G-QQQ.DETAILED DESCRIPTION

[0060] In aspects, the present disclosure provides an enveloped delivery vehicle (EDV), comprising, consisting of, consisting essentially of: (1) an envelope membrane; (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelopemembrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same.

[0061] As used herein, a “membraned vesicle” is a vesicle bound (delimited) by a lipid bilayer. In aspects, the membraned vesicle is either naturally-derived or engineered. A membraned vesicle can be cell-derived and thus be a cell-derived enveloped particle (CDEP). In aspects, the present disclosure provides a membraned vesicle comprising, consisting essentially of, or consisting of a recombinant fusion protein as described herein.

[0062] In aspects, the vesicle is a gesicle or an exosome. A gesicle can be as described in Mangeot et al., Mol. Ther., 19: 1656-1666 (2011), which is incorporated herein by reference in its entirety, where overexpression of glycoprotein of VSV-G in human cells induced release of fusogenic vesicles. As used herein, an “exosome” refers to a lipid bilayer vesicle ranging in size from approximately 30 nm to 150 nm in diameter, secreted by eukaryotic cells via the endosomal pathway, and containing biologically active molecules such as proteins, lipids, RNA, or DNA. An exosome typically originates from multivesicular bodies (MVBs) and is released into the extracellular environment through exocytosis. Exosomes are known to serve as intercellular communication vehicles and may be utilized for diagnostic, therapeutic, or drug delivery applications. Examples of exosomes are provided in Li et al., European Journal of Medicinal Chemistry 207: 112784 (2020); Yang et al., Adv. Mater. 29: 1605604 (2017); U.S. Pat. No. 10,195,290; and U.S. Patent Application Publication No. 2018 / 0028600, each of which is incorporated herein by reference in its entirety.

[0063] As used herein, an “enveloped viral particle” is a vesicle bound (delimited) by a lipid bilayer and has the ability to infect a cell and produce additional enveloped viral particles. An enveloped viral particle can include one or more components of a virus, in addition to a rhabdoviral G glycoprotein or functional fragment or derivative thereof or recombinant fusion protein thereof. Exemplary components of a virus include, without limitation, the gag,pol, or env gene or gene product of lentivirus. In aspects, the present disclosure provides an enveloped viral particle comprising, consisting essentially of, or consisting of a recombinant fusion protein as described herein.

[0064] A “virus-like particle” as used herein means an enveloped viral particle that cannot produce additional virus-like particles (i.e., is replication-incompetent). Virus-like particles (VLPs) are non-infectious and mimic the conformation of their parental viruses but lack the viral genetic material required for replication. A VLP can contain genetic material / nucleic acid not associated with self-replication. VLPs can preserves the high packaging efficiency and target-specificity of certain viruses while greatly minimizing the risk of host genome integration. Because VLPs do not replicate or integrate into the host genome, they are often associated with lower cytotoxicity and reduced immunogenic risk compared to replication-competent viral systems. In aspects, the present disclosure provides a virus-like particle comprising, consisting essentially of, or consisting of a recombinant VMG as described herein.

[0065] In aspects, membraned vesicles, cell-derived enveloped particles, enveloped viral particles, and virus-like particles can encapsulate proteins, lipids, nucleic acids, etc. for delivery, such that membraned vesicles, cell-derived enveloped particles, enveloped viral particles, and virus-like particles can be considered “enveloped delivery vehicles.”

[0066] An “enveloped delivery vehicle” (EDV) can encapsulate a cargo or payload. Any suitable cargo or payload of an EDV is contemplated herein, including, but not limited to, e.g., a protein, a lipid, a nucleic acid, a small molecule, a therapeutic agent, a gene editing system, such as CRISPR Cas, and any combination thereof.

[0067] A “membrane-anchored glycoprotein” (MAG) is a glycoprotein associated with a lipid bilayer membrane. Association with a lipid bilayer can be covalently attached to the membrane. A MAG can be an integral protein, such as a transmembrane protein, or a peripheral protein associated with a surface of a membrane (inner surface or outer surface). In aspects, several peripheral MAGs can, e.g., coat a surface of a membrane. In aspects, several peripheral MAGs can coat a surface of a membrane with several separate MAGs coating the other surface of the membrane. A “viral membrane glycoprotein” (VMG) is a MAG that is from a virus or derived from a virus. A “fusogenic membrane glycoprotein” (FMG) is a MAG that comprises a glycoprotein capable of fusing lipid bilayers. A MAG can comprise an FMG, and a VMG can comprise an FMG. A MAG can comprise a cytoplasmic domain incapable of incorporation into certain membraned vesicles, e.g., EDVs. A MAG comprising a cytoplasmic domain incapable of incorporation can, but does not necessarily, prevent a membraned vesicle from encapsulating cargo / payload, rendering the membraned vesicle incapable of delivery of cargo / payload. The VMGs may be any suitable glycoprotein. Forexample, the VMGs may be a Type 1 membrane glycoprotein (N-terminus opposite the lumen, C-terminus inside the lumen) or a Type 2 membrane glycoprotein (C -terminus opposite the lumen, N-terminus inside the lumen).

[0068] In aspects, the recombinant VMG is untargeted. As used herein the term “untargeted” refers to a recombinant VMG that does not comprise a targeting molecule. As used herein, the term “non-chimeric” refers to a recombinant VMG that does not comprise parts of different proteins.

[0069] In aspects, the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulin-like growth factor receptor.

[0070] In aspects, the recombinant VMG comprises a targeting molecule. Any suitable targeting molecule can be used. As used herein, the term “chimeric” refers to a recombinant VMG that comprises parts of at least two different proteins, such as a rhabdoviral G glycoprotein and a targeting molecule. “Targeting polypeptide” and “targeting molecule” are used interchangeably herein. As used herein, the term “targeting molecule” refers to a binding moiety (that can bind or that can be bound), such as a natural ligand, antibody, multispecific binding molecule, or others known in the art. The targeting molecule can target any suitable cell type. Non-limiting examples of cell types include hematopoietic stem cells (HSC), T cells, monocytes, and NK cells. For HSC, non-limiting examples of markers that can be targeted by the targeting molecule include, e.g., one or more of CD34, CD46, CD90 (Thy-1), CD133, CD135 (Flt3) and CD201 (EPCR). For T cells, non-limiting examples of markers that can be targeted by the targeting molecule include, e.g., one or more of TRBC1, CD3, CD4, CD5, CD7, CD8 and CD30. For monocytes, non-limiting examples of markers that can be targeted by the targeting molecule include, e.g., one or more of CD14, CD1 lb, CD33, CD47, CD123 (IL-3Ra), CD116 / CD131, and CSF1R. For NK cells, non-limiting examples of markers that can be targeted by the targeting molecule include, e.g., one or more ofB7-H6, CS1(SLAMF7), CD16 (FcyRIIIa), CD56, and NKG2D.

[0071] In aspects, a targeting molecule specifically binds a cell surface molecule, e.g., an oligosaccharide, a receptor, cell surface marker, etc., expressed on the surface of a mammalian (e.g., human) eukaryotic cell. In aspects, a targeting molecule binds a (e.g., human) liver cell, a (e.g., human) brain cell, a (e.g., human) T cell, a (e.g., human) kidney cell, a (e.g., human) intestinal cell, a (e.g., human) lung cell, a (e.g., human) cancerous cell, or a (e.g., human) cell infected with heterologous pathogen. In aspects, the targeting moleculebinds a receptor expressed by a (e.g., human) liver cell, e.g., an asialoglycoprotein receptor, e.g., hASGRl. In aspects, the targeting molecule binds a molecule expressed by a (e.g., human) neuronal cell, e.g., GABA, transferrin, etc. In aspects, the targeting molecule binds a receptor or molecule expressed by a (e.g., human) T cell, e.g. CD3, CD4, CD8, T cell receptor (TCR), thrombopoietin receptor (TPO-R), which is also known as cMpl, cKit receptor, which is also known as CD117, etc. In aspects, the targeting molecule binds CD63. In aspects, the targeting molecule binds a molecule expressed by a (e.g., human) hematopoietic stem cell, e.g., CD34. In aspects, the targeting molecule binds a molecule expressed by a (e.g., human) kidney cell. In aspects, the targeting molecule binds a molecule expressed by a (e.g., human) muscle cell, e.g., an integrin. In aspects, the targeting molecule binds a molecule expressed by a (e.g., human) cancerous cell, e.g., a tumor associated antigen, e.g., adipophilin, AIM-2, ALDHIAI, alpha-actinin-4, alpha-fetoprotein (“AFP”), ARTCI, B-RAF, BAGE-1, BCLX (L), BCR-ABL fusion protein b3a2, beta-catenin, BING-4, CA-125, CALCA, carcinoembryonic antigen (“CEA”), CASP-5, CASP-8, CD274, CD45, Cdc27, CDK12, CDK4, CDKN2A, CEA, CLPP, COA-1, CPSF, CSNKIAI, CTAGI, CTAG2, cyclin DI, Cyclin-Al, dek-can fusion protein, DKKI, EFTUD2, Elongation factor 2, ENAH (hMena), Ep-CAM, EpCAM, EphA3, epithelial tumor antigen (“ETA”), ETV6- AML1 fusion protein, EZH2, E6, E7, FGF5, FLT3-ITD, FNI, G250 / MN / CAIX, GAGE- 1,2,8, GAGE- 3, 4, 5, 6, 7, GAS7, glypican-3, GnTV, gplOO / Pmell 7, GPNMB, HAUS3, Hepsin, HER-2 / neu, HERV-K-MEL, HLA-A1 1, HLA-A2, HLA-DOB, hsp70-2, IDOI, IGF2B3, IL13Ralpha2, Intestinal carboxyl esterase, K-ras, Kallikrein 4, KIF20A, KK-LC-1, KKLCI, KM-HN-1, KMHNI also known as CCDCI 10, LAGE-I, LDLR- fucosyltransferaseAS fusion protein, Lengsin, M-CSF, MAGE-A1, MAGE-AIO, MAGE-A12, MAGE-A2, MAGE- A3, MAGE-A4, MAGE-A6, MAGE-A9, MAGE-CI, MAGE-C2, malic enzyme, mammaglobin-A, MART2, MATN, MCIR, MCSP, mdm-2, MEI, Melan-A / MART- 1, Meloe, Midkine, MMP-2, MMP-7, MUCI, MUC5AC, mucin, MUM-I, MUM-2, MUM-3, Myosin, Myosin class I, N-raw, NA88- A, neo-PAP, NFYC, NY-BR-I, NY-ESO-l / LAGE-2, OAI, OGT, OS-9, P polypeptide, p53, PAP, PAX5, PBF, pml-RARalpha fusion protein, polymorphic epithelial mucin (“PEM”), PPPIR3B, PRAME, PRDX5, PSA, PSMA, PTPRK, RAB38 / NY-MEL-1, RAGE-I, RBAF600, RGS5, RhoC, RNF43, RU2AS, SAGE, secemin 1, SIRT2, SNRPDI, SOXIO, Spl7, SPA17, SSX-2, SSX-4, STEAPI, survivin, SYT-SSXI or - SSX2 fusion protein, TAG-I, TAG-2, Telomerase, TGF-betaRII, TPBG, TRAG-3, Triosephosphate isomerase, TRP-l / gp75, TRP-2, TRP2-INT2, tyrosinase, tyrosinase(“TYR”), VEGF, WTI, XAGE-lb / GAGED2a, Kras, NYESOI, HPV E2, HPV E6, HPV E7, WT-I antigen (in lymphoma and other solid tumors), ErbB receptors, Melan A [MARTI], gp 100, tyrosinase, TRP-l / gp 75, and TRP-2 (in melanoma); MAGE-I and MAGE-3 (in bladder, head and neck, and non-small cell carcinoma); HPV EG and E7 proteins (in cervical cancer); Mucin [MUC-1] (in breast, pancreas, colon, and prostate cancers); prostate-specific antigen [PSA] (in prostate cancer); carcinoembryonic antigen [CEA] (in colon, breast, and gastrointestinal cancers), and such shared tumor-specific antigens as MAGE-2, MAGE-4, MAGE-6, MAGE-10, MAGE-12, BAGE-1, CAGE-1,2,8, CAGE-3 TO 7, LAGE-I, NY- ESO-l / LAGE-2, NA-88, GnTV, TRP2-INT2, etc. In aspects, the targeting molecule binds E6 and / or E7. In aspects, the targeting molecule binds Her2. In aspects, the targeting molecule binds CD63. In aspects, the targeting molecule binds human glucagon receptor (hGCGR). In aspects, the targeting molecule binds human ectonucleoside triphosphate diphosphohydrolase 3 (hENTPD3).

[0072] In aspects, the targeting molecule is capable of selectively binding to a receptor expressed by a HSC, a mast cell, a melanocyte, and / or a germ cell. In aspects, the receptor is a c-Kit receptor (also known as CD117). In preferred aspects, the c-Kit receptor is expressed by a HSC. In aspects, the targeting molecule is capable of initiating the c-Kit receptor to homodimerize and auto-phosphorylate at tyrosine residues. In aspects, the targeting molecule is an anti-cKit binding domain or a functional fragment or derivative thereof capable of selectively binding to the cKit receptor, which is sometimes abbreviated as c-KIT or ckit. In aspects, the anti-cKit binding domain comprises an anti-cKit 2D1 scFv (SEQ ID NOs: 70 and 71) or a functional fragment or derivative thereof.

[0073] As used herein, “hematopoietic stem cell” or “HSC” refers to a multipotent primitive cell with the capability to self-renew and develop into all types of blood cells, including myeloid-lineage and lymphoid-lineage cells. HSCs may be categorized as longterm or short-term HSCs. As used herein, “long-term HSC” or “LT-HSC” refers to a hematopoietic stem cell characterized by its ability to self-renew and differentiate into various blood cell types over extended periods, typically months to years. A small percentage of blood cells are LT-HSCs, which are typically the target cells for gene editing. In mice LT- HSCs are typically CD34 negative (CD34-) (Matsuoka et al., “CD34 expression on long-term repopulating hematopoietic stem cells changes during developmental stages,” Blood,419-425 (2001)). In humans LT-HSCs are typically CD34 positive (CD34+), although a population of CD34- LT-HSCs have been identified in human hematopoietic tissue, includingbone marrow (Hughes et al., “A sticky wicket: Defining molecular functions for CD34 in hematopoietic cells,” Experimental Hematology, 86: 1-14 (2020)). Human LT-HSCs can be CD34+ CD38- CD90+ Lin- (CD34 plus, CD38 minus, CD90 plus, Lin minus) cells. As used herein, “short-term HSC” or “ST-HSC” refers to a stem cell distinguished by its relatively limited self-renewal capacity and more immediate differentiation into specialized cell types, typically weeks to months. In aspects, the HSC is a long-term HSC.

[0074] As used herein, “hematopoietic progenitor cell” or “HPC” refers to a multipotent, oligopotent, or unipotent cell lacking significant self-renewal capacity but capable of differentiating further into mature blood cells of all hematopoietic lineages. As used herein, “hematopoietic stem and progenitor cell” or “HSPC” is a term that encompasses both HSCs and HPCs.

[0075] As used herein, “hepatic sinusoidal endothelial cell” or “HSEC” refers to a specialized endothelial cell that lines the hepatic sinusoids within the liver. HSECs play a role in multiple liver-specific functions such as selective nutrient exchange, vascular permeability, immune surveillance, and maintaining hepatic blood flow and metabolism.

[0076] CD45, also known as protein tyrosine phosphatase receptor type C (PTPRC), is a transmembrane glycoprotein and protein tyrosine phosphatase expressed on the surface of all nucleated hematopoietic cells, including HSCs, HPCs and HSPCs, except that of erythrocytes and platelets. CD45 is known to regulate T and B cell receptor signaling, immune cell activation, proliferation, differentiation, and survival. Abnormal CD45 expressions or functions are associated with immunodeficiencies, autoimmune diseases, leukemias, and lymphomas. Notably, CD45 is not expressed on hepatic sinusoidal endothelial cells (HSECs), distinguishing these liver cells from hematopoietic lineage cells as shown in Table 8 below.Table 8

[0077] In aspects, at least one targeting molecule is a ligand. In aspects, the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1). In aspects, the ligand is epidermal growth factor (EGF), a mutant EGF (EFGml23) (SEQ ID NO: 34), stem cell factor (SCF) (SEQ ID NO: 28), thrombopoietin (TPO) (SEQ ID NO: 31), human hepatocyte growth factor (HGF) (SEQ ID NO: 32), or type 1 insulin-like growth factor (IGF1) (SEQ ID NO: 33).

[0078] In aspects, the targeting molecule is a SCF or a functional fragment or derivative thereof. In aspects, the SCF is a mouse SCF (mSCF) (e.g., SEQ ID NO: 29 or 30) or a functional fragment or derivative thereof. In aspects the SCF is a human SCF (hSCF) (SEQ ID NO: 28) or a functional fragment or derivative thereof. In aspects, the SCF comprises a mutation. In aspects, the SCF comprises a substitution of F63A (SEQ ID NO: 68).

[0079] In aspects, the targeting molecule is functionally modified, e.g., by conservative amino acid substitution. For example, in aspects, the targeting molecule is a mSCF ligand that is modified with an alanine substitution at residue 63 (F63A) (SEQ ID NO: 68) to, e.g., reduce dimerization, causing mSCF F63 A to act as a monomer in solution. In aspects, the targeting molecule is a mSCF ligand that is modified with N6D, D77H, K81I, V87F, L88F, and / or S101F substitutions (6mut) (SEQ ID NO: 67), e.g., to increase binding affinity for cKit. In aspects, the targeting molecule is a mSCF ligand that is modified to have both F63 Aand 6mut substitutions (F63A-6mut) (SEQ ID NO: 69), e.g., to reduce dimerization and increase binding affinity for cKit. Functional modifications to targeting molecules can be beneficial, e.g., for fine tuning binding affinity and avoiding cross-reactivity with other cell types, such as Mast cells.

[0080] In aspects, the targeting molecule comprises a thrombopoietin (TPO) (SEQ ID NO: 31) or a functional fragment or derivative thereof. In aspects, the TPO is capable of binding to and activating the TPO receptor (TPO-R) also known as the myeloproliferative leukemia protein (cMpl) expressed on the surface of HSCs. In aspects, this binding facilitates the activation of signal transduction pathways that promote cell proliferation, survival, and maturation of the target cell.

[0081] In aspects, at least one targeting molecule is an antibody or portion thereof. In aspects, the antibody or portion thereof is a single-chain variable fragment (scFv), a nanobody, or a minibody. In aspects, the portion thereof is an antigen-binding fragment. In aspects, the antibody or portion thereof is a single chain fragment variable (scFv), an affibody, a diabody, a minibody, a nanobody, a single-domain antibody (sdAb), or a single heavy chain antibody. Also contemplated herein are polypeptide antibody constructs, monoclonal antibodies, human antibodies, humanized antibodies, chimeric antibodies, single chain antibodies, Fab fragments, F(ab') fragments, disulfide-linked Fvs (sdFv), intrabodies, and anti -idiotypic (anti-Id) antibodies (including, e.g., anti-Id antibodies to antigen specific TCR), Ig-DARTS, epitope-binding fragments of any of the above, and what is described in US Patent Publication No. 2007 / 0004909 and US Patent Publication No. 2009 / 0060910, each of which is incorporated herein by reference in their entireties). Also contemplated are immunoglobulin molecules and immunologically active fragments of immunoglobulin molecules, i.e., molecules that contain an antigen binding site. Immunoglobulin molecules can be of any type (e.g., IgG, IgE, IgM, IgD, IgA and IgY), class (e.g., IgGI, IgG2, IgG3, IgG4, IgAI and IgA2) or subclass. In aspects, the targeting molecule is an antibody comprising a variable domain that binds a cell surface protein on a target cell and a heavy chain constant domain. In aspects, the targeting molecule is an antibody comprising a variable domain that binds a cell surface protein on a target cell and an IgG heavy chain constant domain. In aspects, the targeting molecule is an antibody comprising a variable domain that binds a cell surface protein on a target cell and an IgG heavy chain constant domain.

[0082] In aspects, the targeting molecule is a single chain variable fragment (scFv). In aspects, the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97. In aspects, the VH is N-terminal to the VL. In aspects, the VL is N- terminal to the VH. In aspects, the VH and VL are separated by a flexible linker. In aspects, the flexible linker comprises SEQ ID NO: 17.

[0083] In aspects, the scFv binds epidermal growth factor (EGF), human epidermal growth factor receptor 2 (Her2), cluster of differentiation 3 (CD3), cluster of differentiation 4 (CD4), cluster of differentiation 8 (CD8), or cluster of differentiation 117 (CD117 or cKit), mucin- 16 (MUC16), B cell maturation antigen (BCMA), or Nectin4.

[0084] In aspects, the targeting molecule is agonistic to CD3. In aspects, the scFv comprises a VH of SEQ ID NO: 27 and a VL of SEQ ID NO: 26 wherein the VH and VL are separated by a flexible linker comprising SEQ ID NO: 17 and the VL is N-terminal to the VH. In aspects, the polypeptide antibody construct comprises a single chain variable fragment (scFv). In aspects, the scFv has the VL N-terminal to VH. In aspects, the scFv has the VH N-terminal to VL. In aspects, the scFv is UCHT1, HuM291, OKT3, or TR66. In aspects, the scFv is a humanized UCHT1. In aspects, the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 27 and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 26. In aspects, the VH and VL are separated by a flexible linker. In aspects, the flexible linker is SEQ ID NO: 17. In aspects, the scFv is TR66 and wherein the TR66 is codon optimized for expression in human (TR66opt) and wherein the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 25 and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 24. In aspects, the scFv is TR66opt and wherein the scFv comprisesa variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequences of a complementarity determining region 1 (CDR1) of SEQ ID NO: 131, a complementarity determining region 2 (CDR2) of SEQ ID NO: 132, and a complementarity determining region 3 (CDR3) of SEQ ID NO: 133, and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 134, a CDR2 of SEQ ID NO: 135, and a CDR3 of SEQ ID NO: 136. In aspects, the scFv is UCHT1 wherein the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 27 and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 26. In aspects, the scFv is UCHT1 and wherein the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 107, a CDR2 of SEQ ID NO: 108, and a CDR3 of SEQ ID NO: 109, and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 110, a CDR2 of SEQ ID NO: 111, and a CDR3 of SEQ ID NO: 112. In aspects, the scFv is HuM291 wherein the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 19 and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 18. In aspects, the scFv is Hum291 and wherein the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 119, a CDR2 of SEQ ID NO: 120, and a CDR3 of SEQ ID NO: 121, and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 122, a CDR2 of SEQ ID NO: 123, and a CDR3 of SEQ ID NO: 124. In aspects, the scFv is OKT3 wherein the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 21 and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 20. In aspects, the scFv is OKT3 and wherein the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 125, a CDR2 of SEQ ID NO: 126, and a CDR3 of SEQ ID NO: 127, and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 128, a CDR2 of SEQ ID NO: 129, and a CDR3 of SEQ ID NO: 130. In aspects, the scFv is TR66 wherein the scFv comprises a variable heavychain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 23 and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 22. In aspects, the scFv is TR66 and wherein the scFv comprises a variable heavy chain (VH) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 113, a CDR2 of SEQ ID NO: 114, and a CDR3 of SEQ ID NO: 115, and a variable light chain (VL) comprising, consisting essentially of, or consisting of the amino acid sequences of a CDR1 of SEQ ID NO: 116, a CDR2 of SEQ ID NO: 117, and a CDR3 of SEQ ID NO: 118.

[0085] In aspects, the targeting molecule is agonistic to CD4. In aspects, the scFv comprises a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, wherein the VH and VL are separated by a flexible linker comprising SEQ ID NO: 17 and the VL is N-terminal to the VH. In aspects, the scFv comprises a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, or a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, wherein the VH and VL are separated by a flexible linker comprising SEQ ID NO: 17 and the VH is N-terminal to the VL.

[0086] In aspects, the targeting molecule is agonistic to CD8. In aspects, the scFv comprises a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97, wherein the VH and VL are separated by a flexible linker comprising SEQ ID NO: 17 and the VH is N-terminal to the VL.

[0087] In aspects, the antibody or portion thereof is a nanobody. In aspects, the nanobody comprises SEQ ID NO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103. In aspects, the nanobody is agonistic to CD4. In aspects, the nanobody is agonistic to CD4 and comprises SEQ ID NO: 100 or SEQ ID NO: 101. In aspects, the nanobody is agonistic to CD8. In aspects, the nanobody is agonistic to CD8 and comprises SEQ ID NO: 102 or SEQ ID NO: 103.

[0088] In aspects, the antibody or portion thereof is a minibody. In aspects, the minibody comprises SEQ ID NO: 104. In aspects, the minibody, is agonistic to CD8. In aspects, the minibody is agonistic to CD8 and comprises SEQ ID NO: 104.

[0089] In aspects, at least one FMG is N-terminal to at least one targeting molecule in at least one VMG. In aspects, at least one targeting molecule is N-terminal to at least one FMG in at least one VMG. In aspects, at least one VMG comprises a linker between at least one FMG and at least one targeting molecule. Any suitable linker is contemplated, e.g., as disclosed in Chen et al., Adv. Drug. Deliv. Rev., 65(10: 1357-1369 (2013), which is incorporated herein by reference in its entirety. In aspects, the linker is flexible. Exemplary flexible linkers include, but are not limited to, e.g.,AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49), AAASGGSGGGGSGGGGS (SEQ ID NO: 50), GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51), GGGGSGGGGSGGGGS (SEQ ID NO: 17), GGGGSGGGGS (SEQ ID NO: 52), GGGGS (SEQ ID NO: 53), GGGGGGGG (SEQ ID NO: 54), GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), and VPGVGVPGVG (SEQ ID NO: 57).

[0090] In aspects, the linker is rigid. Exemplary rigid linkers include, but are not limited to, e.g.,PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59), EAAAKEAAAK (SEQ ID NO: 60), EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63), ESKYGPPCPPCP (SEQ ID NO: 64), CPPCPAPELLGGPSVF (SEQ ID NO: 65), and alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

[0091] In aspects, the number of VMG(s) of (2) in the envelope membrane is not the same as the number of VMG(s) of (3) in the envelope membrane.

[0092] In aspects, the EDV comprises (4) at least one third recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule.

[0093] In aspects, the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is from 1:1:1 to 1:1:9 or from 1:1:1 to 1:9:1 or from 1:1:1 to 9: 1 : 1. In aspects, the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is 1 : 1 :6. In aspects, the ratio of VMG with a first targeting molecule to VMG with a second targeting molecule to VMG without a targeting molecule is from 1 :9:0 to 9: 1 :0 or from 1:1:9 to 1:9:1 to 9:1:1. The ratio of VMG with a first targeting molecule to VMG with a second targeting molecule to VMG without a targeting molecule can be of any amount from 1:9:0 to 9:1:0 or from 1:1:9 to 1:9:1 to 9:1:1, e.g. a ratio of 1:9:0, 1:8:0, 1:7:0,1:6:0, 1:5:0, 1:4:0, 1:3:0, 2:1:0, 1:1:0, 1:2:0, :3:l:0, 4:1:0, 5:1:0, 6:1:0, 7:1:0, 8:1:0, 9:1:0,1:1:9, 1:1:8, 1:1:7, 1:1:6, 1:1:5, 1:1:4, 1:1:3, 1:1:2, 1:1:1, 1:2:1, 1:3:1, 1:4:1, 1:5:1, 1:6:1,1:7:1, 1:8:1, 1:9:1, 2:1:1, 3:1:1, 4:1:1, 5:1:1, 6:1:1, 7:1:1, 8:1:1, 9:1:1 or any range between these ratios. In aspects, the ratio of VMG with a first targeting molecule to VMG with a second targeting molecule to VMG without a targeting molecule is from 1:1:6.

[0094] In aspects, two or more VMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

[0095] In aspects, at least one FMG is engineered to reduce or eliminate binding to its natural receptor. In aspects, at least one FMG comprises a rhabdoviral G protein.

[0096] Rhabdoviruses are viruses within the family Rhabdoviridae . The viruses encode proteins denoted N (nucleoprotein), P (phosphoprotein), M (matrix protein), G (glycoprotein), and L (large protein, which is a polymerase), and the viruses appear to have a shape of a bullet when observed using electron microscopy. Dimensions of rhabdovirus virions can range from 100 nm to 430 nm in length and can range from 45 nm to 100 nm in diameter.

[0097] Rhabdoviral G glycoprotein mediates binding of rhabdovirus to a receptor on a cell, which binding then mediates entry of the rhabdovirus into the cell and infection of the cell. A rhabdoviral G glycoprotein or functional fragment or derivative thereof as described herein, including recombinant VMGs comprising the rhabdoviral G glycoprotein or functional fragment or derivative thereof, can be used to pseudotype a type of virus that is not the native / natural virus of the rhabdoviral G glycoprotein.

[0098] As used herein, a “pseudotype” of a virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc. means a virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc. comprising a molecule, e.g., a rhabdoviral G glycoprotein or functional fragment or derivative thereof (including a recombinant VMG comprising the rhabdoviral G glycoprotein or functional fragment or derivative thereof), that is not typically found in the virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc. Such a molecule can have a mutation (e.g., a substitution or deletion) that impacts the tropism of the virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc. The impact on tropism can be, e.g., to contribute to, direct, redirect, or completely change, or any combination thereof, the tropism of the virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc. when compared to the virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc. without the molecule and / or compared to the wild-type virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc. The impact on tropism can be, e.g., to target a cell that is different from the cell normally targeted by the virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc. and / or to not target a cell that is normally targeted by the virus, membraned vesicle, enveloped delivery vehicle, enveloped viral particle, or recombinant viral vector, etc.

[0099] As used herein, “functional fragment” of a rhabdoviral G glycoprotein means a rhabdoviral G glycoprotein that is not a full length rhabdoviral G glycoprotein but is a portion of a parent rhabdoviral G glycoprotein (e.g., a truncated form of a full length rhabdoviral G glycoprotein), where the portion retains the fusion function of the parent full length rhabdoviral G glycoprotein. As used herein, “functional derivative” or “functional variant” of a rhabdoviral G glycoprotein means a rhabdoviral G glycoprotein that has been modified, e.g., by conservative amino acid substitution, where the rhabdoviral G glycoprotein retains the fusion function of the parent full length rhabdoviral G glycoprotein. As used herein, “functional fragment or derivative” and “functional fragment or variant” encompass the meanings of both “functional fragment” and “functional derivative” / “functional variant.” In aspects, the amino acid sequence of functional derivative or functional variant of a rhabdoviral G protein has 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, 85%, 80% 75%, 70%, 65%, or 60% sequence identity compared to a rhabdoviral G proteindescribed herein. In aspects, the rhabdoviral G protein or functional fragment or derivative thereof contains one or more conservative amino acid substitutions that do not interfere with the fusion function of the rhabdoviral G protein or functional fragment or derivative thereof.

[0100] The “fusion function” of a rhabdoviral G protein means that a rhabdoviral G protein, when part of a virus, can initiate fusion of the virus with a target cell, e.g., such that the virus can infect the target cell. Such fusion can be due to the interaction of the rhabdoviral G protein with a natural receptor or the interaction of the rhabdoviral G protein with a different receptor (e.g., the rhabdoviral G protein is blinded to a natural receptor, such that the rhabdoviral G protein is engineered to reduce or abolish a natural receptor binding specificity, and the rhabdoviral G protein is re-targeted to a new receptor). As used herein, the term “natural receptor” refers to a endogenously expressed receptor in an organism that a rhabdoviral G protein is capable of binding. Any rhabdoviral G protein may have more than one natural receptor. As used herein, the term “receptor blinded” refers to a rhabdoviral G protein with reduced or abolished binding specificity for a natural receptor. A functional fragment and / or functional derivative / functional variant of a rhabdoviral G protein can be within a recombinant VMG comprising a rhabdoviral G protein.

[0101] In aspects, an enveloped delivery vehicle, membraned vesicle, or enveloped viral particle comprises enveloped delivery vehicle described herein comprises a mixed trimer. In aspects, the mixed trimer of the enveloped delivery vehicle, membraned vesicle, or an enveloped viral particle comprises at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule, at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule, and at least one third recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same. In aspects, the first targeting molecule comprises EGF, CD19, CD20, CD4, CD28, TPO, or SCF and the second targeting molecule comprises a-CD19, a-CD3, or a-c-Kit. In aspects, the first targeting molecule comprises a-CD19, a-CD3, or a-c-Kit and the second targeting molecule comprises EGF, CD19, CD20, CD4, CD28, TPO, or SCF.

[0102] Without being bound by theory, decreasing the number of units in a recombinant rhabdoviral G glycoprotein trimer that have a targeting molecule better allows the transformation of the trimer from a prefusion to a fusion conformation.

[0103] In aspects, the enveloped delivery vehicle, membraned vesicle, or enveloped viral particle comprises an unmixed trimer, wherein the unmixed trimer comprises only recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule. In aspects, the enveloped delivery vehicle, membraned vesicle, or enveloped viral particle comprises an unmixed trimer, wherein the unmixed trimer comprises at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule, at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule, and does not comprise any recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG not comprising a targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same.

[0104] Rhabdoviral G proteins can associate into trimers at the surface of a native virus, an enveloped delivery vehicle as described herein, a membraned vesicle as described herein, an enveloped viral particle as described herein, or a recombinant viral vector as described herein. As used herein, a “mixed rhabdoviral G protein trimer” comprises, consists essentially of, or consists of three rhabdoviral G proteins or functional fragments or derivatives thereof (wherein each is optionally within a recombinant fusion protein), wherein (a) at least one of the rhabdoviral G proteins or functional fragments or derivatives thereof in the trimer is within a recombinant fusion protein comprising, consisting essentially of, or consisting of a rhabdoviral G protein or a functional fragment or derivative thereof engineered to reduce or abolish natural receptor binding specificity and a targeting molecule, and (b) at least one of the rhabdoviral G proteins or functional fragments or derivatives thereof in the trimer is not within a recombinant fusion protein and does not have a targeting molecule.

[0105] Trimers of rhabdoviral G proteins or functional fragments or derivatives thereof, may have one, two, or three targeting molecules. The number of targeting molecules in the trimer is the occupancy of the trimer, wherein the trimer may have full occupancy (threetargeting molecules in the trimer), partial occupancy (targeting molecules on fewer than all rhabdoviral G proteins or functional fragments or derivatives thereof of the trimer, e.g., two or one targeting molecules), or no occupancy (no targeting molecule in the trimer). In aspects, trimers of rhabdoviral G proteins or functional fragments or derivatives thereof having full occupancy or partial occupancy comprise targeting molecules with the same identity (i.e., two identical targeting molecules or three identical targeting molecules). In aspects, trimers of rhabdoviral G proteins or functional fragments or derivatives thereof having full occupancy or partial occupancy comprise at least two different targeting molecules (e.g., three distinct targeting molecules).

[0106] In aspects, an enveloped delivery vehicle, a membraned vesicle, or an enveloped viral particle comprises the maximum number of the recombinant VMGs possible to be accommodated within the membrane of the enveloped delivery vehicle, membraned vesicle, or enveloped viral particle, wherein each recombinant VMG comprises a targeting molecule. In aspects, an enveloped delivery vehicle, a membraned vesicle, or an enveloped viral particle comprises less than the maximum number of the recombinant VMGs possible to be accommodated within the membrane of the enveloped delivery vehicle, membraned vesicle, or enveloped particle, wherein each recombinant VMG comprises a targeting molecule. Less than the maximum amount can be of any amount less than 100%, e.g., 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5%, 2%, or 1%, or any range between these percentages. In aspects, any enveloped delivery vehicle as described herein comprises the maximum number of the recombinant VMGs possible to be accommodated within the membrane, wherein each recombinant VMG comprises a targeting molecule.

[0107] In aspects, the recombinant VMG comprises a rhabdoviral G glycoprotein or functional fragment or derivative thereof. In aspects, the rhabdoviral G protein is of a Flanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein (RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawaraglycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), a Bovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), a Niakha glycoprotein (NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G). In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is from any rhabdoviral G glycoprotein or functional fragment or derivative thereof as provided herein.

[0108] In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is of Vesiculovirus glycoprotein or a functional fragment or derivative thereof. In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is of Vesiculovirus Indiana (e.g., SEQ ID NO: 9, 105, 186, or 138), Vesiculovirus newjersey (e.g., SEQ ID NO: 48 or 99), Vesiculovirus carajas (e.g., SEQ ID NO: 11 or 188), Vesiculovirus alagoas (e.g., SEQ ID NO: 12 or 189), Vesiculovirus cocal (e.g., SEQ ID NO: 47 or 190), Vesiculovirus maraba (e.g., SEQ ID NO: 187 or 98), Vesiculovirus morreton (e.g., SEQ ID NO: 191 or 192), or any other rhabdoviral G glycoprotein or functional fragment or derivative thereof as provided herein. In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is of Vesiculovirus indiana (e.g., SEQ ID NO: 9 or 186). In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is of Vesiculovirus newjersey (e.g., SEQ ID NO: 48 or 99). In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is of Vesiculovirus newjersey (SEQ ID NO: 10 or 16). In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is of Vesiculovirus alagoas (e.g., SEQ ID NO: 43, 44, 155, or 158). In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is of Vesiculovirus carajas (e.g., SEQ ID NO: 45, 46, 148, or 151).

[0109] In aspects, the recombinant VMG comprises a rhabdoviral G glycoprotein or functional fragment or derivative thereof that has 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, 85%, 80% 75%, 70%, 65%, or 60% sequence identity compared to a rhabdoviral G glycoprotein or functional fragment or derivative thereof described herein. In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof contains one or more conservative amino acid substitutions that do not interfere with the fusion function of the rhabdoviral G glycoprotein or functional fragment or derivative thereof.

[0110] In aspects, the recombinant VMG comprises a rhabdoviral G glycoprotein that is substantially intact. As used herein, a “substantially intact” rhabdoviral G glycoprotein means a rhabdoviral G glycoprotein that is a functional fragment of the rhabdoviral G glycoprotein, where the rhabdoviral G glycoprotein has each of the domains of a rhabdoviral G glycoprotein, the domains as defined in Roche et al., Cell. Mol. Life Sci., 65: 1716-1728 (2008), which is incorporated herein by reference in its entirety.[OHl] In aspects, the recombinant VMG comprises a rhabdoviral G glycoprotein that is a functional fragment or derivative thereof. In aspects, the cytoplasmic tail of the glycoprotein is truncated, deleted, or replaced with another sequence. Previous work has shown that such truncation or deletion can enhance fusion activity in rhabdoviral G glycoprotein. In aspects, the truncations from the C terminus can be, for example, 1 amino acid, 2 amino acids, 3 amino acids, 4 amino acids, 5 amino acids, 6 amino acids, 7 amino acids, 8 amino acids, 9 amino acids, 10 amino acids, 20 amino acids, 30 amino acids, 40 amino acids, 50 amino acids, 60 amino acids, up to 10 amino acids, up to 20 amino acids, up to 30 amino acids, up to 40 amino acids, up to 50 amino acids, up to 60 amino acids, or more than 60 amino acids. In aspects, the cytoplasmic tail is replaced with another sequence.

[0112] In aspects, the recombinant VMG comprises a rhabdoviral G glycoprotein or functional fragment or derivative thereof that is engineered to have a mutation to reduce or abolish its natural receptor binding specificity. Reduction in binding specificity can be of any amount, e.g., reduced by 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5%, 2%, 1%, or any range between these percentages.

[0113] In aspects, the G protein or functional fragment or derivative thereof is fusion competent, has reduced natural tropism, or both. As used herein, the term “fusion competent” refers to a rhabdoviral G protein that, when part of a virus, can initiate fusion of the virus with a target cell, e.g., such that the virus can infect the target cell. A fusion competent G protein or functional fragment or derivative thereof can have increased or decreased fusion efficiency compared to a wild type G protein. Increase in fusion efficiency specificity can be of any amount, e.g., increased by 1%, 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 500%, 1000%, or any range between these percentages. Decrease in fusion efficiency can be of any amount, e.g., decreased by 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5%, 2%, 1%, or any range between these percentages.

[0114] Vesicular stomatitis virus (VSV) is a rhabdovirus, having a natural receptor of the low-density lipoprotein receptor (LDL-R) or very low density lipoprotein receptor (VLDL-R), which are expressed on the cell membrane of many types of cells. In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is engineered to have a mutation to reduce or abolish a natural receptor binding specificity to LDL-R or VLDL-R, or other receptors which exhibit cross-reactivity to these receptors. In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof comprises a mutation at one or more positions corresponding to H8, K47, Y209, and K354 on the Vesiculovirus Indiana glycoprotein (SEQ ID NO: 9). In aspects, the mutation is a substitution of a wild-type amino acid to another amino acid. In aspects, the substitution is with a Q. In aspects, the mutation is a substitution at three or more positions corresponding to H8, K47, Y209, and K354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9). In aspects, the mutation comprises, consists of, or consists essentially of the amino acid sequence of SEQ ID NO: 14, 36, 37, 38,141, 143, 145, 149, 152, or 156. The US Patent Publication No. 2020 / 0216502 is incorporated herein by reference in its entirety. In aspects, the mutation is a deletion of a wild-type amino acid. In aspects, the mutation is deletion of one or more positions corresponding to H8, K47, Y209, and K354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9), wherein each deleted amino acid is not present within the amino acid sequence of the glycoprotein. In aspects, the mutation is a single deletion at K47, wherein the K47 amino acid is not present within the amino acid sequence of the glycoprotein. In aspects, the mutation comprises, consists of, or consists essentially of the amino acid sequence of SEQ ID NO: 15, 16, 142, 144, 146, 147, 150, 153, 154, or 157.

[0115] In aspects, preferred full length rhabdoviral G glycoproteins, ectodomains, signal peptides, and engineered mutations of the ectodomains to reduce or abolish its natural receptor binding affinity are shown in Table 9. VSV indicates Vesiculovirus indiana G glycoprotein, VSNJV indicates Vesiculovirus newjersey G glycoprotein, VSCV indicates Vesiculovirus carajas G glycoprotein, VS AV indicates Vesiculovirus alagoas G glycoprotein, VSCOV indicates Vesiculovirus cocal G glycoprotein, KEUV indicates Keuraliba virus G glycoprotein, KRV indicates Kumasi virus G glycoprotein, WT indicates wild type, 41 J indicates residue 41 can be an I or L, KIR indicates a R substitution at residue 1 corresponding to SEQ ID NO: 9, G115A indicates an A substitution at residue 115 corresponding to SEQ ID NO: 9, Delta K47 indicates a deletion at residue 47 corresponding to SEQ ID NO: 9, and K47Q+Y209Q+R354Q indicates Q substitutions at residues 47, 209, and 354 corresponding to SEQ ID NO: 9.Table 9

[0116] It has been found that a Vesiculovirus Indiana rhabdoviral G glycoprotein having a deletion of K47 reduces or abolishes the natural receptor binding specificity of the rhabdoviral G glycoprotein when the rhabdoviral G glycoprotein while unexpected retaining full function of the G protein in other respects. In particular, this feature is seen when incorporated into a lentiviral vector. However, when used in a VSV vector, there is a second site mutation (F405I) generated in the VSV-G protein during the virus amplification. This mutation leads to the loss of detargeting effect caused by the deletion on K47 residue. Without wishing to be bound by theory, this phenomenon may be due to VSV being a replicating virus, whereas lentivirus is a non-replicating virus.

[0117] Vesiculovirus indiana glycoprotein having H8 and / or K47 deletions, when incorporated into a lentiviral system, can support production of functional pseudotyped lentivirus and successful cell transduction. The H8 and / or K47 deletions, but not Y209 or R354 deletions or Y209 / R354 deletion combinations, demonstrated generation and rescue of pseudotyped lentivirus with low to no LDL-R background binding.

[0118] In aspects, the recombinant VMG comprises a rhabdoviral G glycoprotein or functional fragment or derivative thereof that comprises one or more viral titer increasing mutations. In aspects, the one or more viral titer increasing mutations is one or both of M184T and F250L in SEQ ID NO: 9 (or the positions corresponding to M184T and F250L). Other exemplary mutations, without limitation, for increasing viral titer include those described in US Patent Publication No. 2022 / 0162266, which is incorporated herein by reference in its entirety. The mutations include H22N and S422I in the ectodomain of Vesiculovirus indiana G glycoprotein (SEQ ID NO: 9) (or substitutions in positions corresponding to these in other rhabdoviral G glycoproteins).

[0119] In aspects, the rhabdoviral G glycoprotein or functional fragment or derivative thereof is mutated to reduce or abolish protease cleavage.

[0120] Amino acid positions of other rhabdoviral G glycoproteins or functional fragments or derivatives thereof that are “positions corresponding to” the amino acids discussed above can be determined using a global sequence alignment algorithm (see, e.g., Madeira et al., Nuc. Acids Res., 50(Wl): W276-W279 (2022), which is incorporated herein by reference in its entirety) comparing the base rhabdoviral G glycoprotein to another rhabdoviral G glycoprotein.

[0121] In aspects, the recombinant VMG comprises a signal peptide. As used herein, a “signal peptide” refers to a peptide involved in targeting a glycoprotein to the secretory pathway. In aspects, different signal peptides can be selected to improve glycoprotein targeting to the secretory pathway. In aspects, the signal peptide may be the naturally occurring signal peptide for the rhabdoviral G glycoprotein. In aspects, the signal peptide comprises the amino acid sequence of a signal peptide as described herein.

[0122] In aspects, the recombinant VMG comprises a tag for western detection or purification. In aspects, the tag is a tag for western detection. In aspects, the tag is a tag for purification. In aspects the tag is a FLAG tag, GFP, or others.

[0123] In aspects, the present disclosure provides a method of generating an enveloped delivery vehicle (EDV), the method comprising, consisting of, consisting essentially of: (a) transfecting or transducing a host cell with at least one expression construct encoding at least two recombinant viral membrane glycoproteins (VMGs); wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same; (b) maintaining the host cell within suitable conditions for at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (1) an envelope membrane; and (2) at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) that are incorporated into the envelope membrane; (I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising asubstantially intact FMG and (B) a first targeting molecule; (II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; and wherein the first targeting molecule and the second targeting molecule are not the same.

[0124] In aspects, the method comprises (a) transfecting or transducing a host cell with: (iii) at least one third expression construct encoding at least one third recombinant VMG; wherein at least one third recombinant VMG comprises a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a targeting molecule; (b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one third expression construct of (iii) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (4) at least one third recombinant VMG encoded by at least one third expression construct of (iii) that is incorporated into the envelope membrane; (III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule.

[0125] In aspects, the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is from 1 : 1 : 1 to 1 : 1 :9 or from 1:1:1 to 1:9:1 or from 1:1:1 to 9:1:1. The ratio of expression construct encoding a VMG with a first targeting molecule to expression construct encoding a VMG with a second targeting molecule to expression construct encoding a VMG without a targeting molecule can be of any amount from 1:9:0 to 9:1:0 or from 1 :1:9 to 1:9:1 to 9:1:1, e.g. a ratio of 1:9:0, 1:8:0, 1:7:0, 1:6:0,1:5:0, 1:4:0, 1:3:0, 2:1:0, 1:1:0, 1:2:0, :3:l:0, 4:1:0, 5:1:0, 6:1:0, 7:1:0, 8:1:0, 9:1:0, 1:1:9,1:1:8, 1:1:7, 1:1:6, 1:1:5, 1:1:4, 1:1:3, 1:1:2, 1:1:1, 1:2:1, 1:3:1, 1:4:1, 1:5:1, 1:6:1, 1:7:1,1:8:1, 1:9:1, 2:1:1, 3:1:1, 4:1:1, 5:1:1, 6:1:1, 7:1:1, 8:1:1, 9:1:1 or any range between these ratios. In aspects, the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is 1 : 1 :6.

[0126] In aspects, transfecting or transducing a host cell comprises transfecting or transducing with at least one packaging plasmid. “Transfecting” and “transfection” as used herein means non-viral means of introducing nucleic acid into a cell. “Transducing” and “transduction” as used herein means use of viral means of introducing nucleic acid into a cell.

[0127] In aspects, any method of making an enveloped delivery vehicle, lentivirus, retroviral vector expression system, recombinant viral vector, etc. as described herein cancomprise transduction in a medium comprising a poloxamer-based chemical adjuvant. In aspects, the poloxamer-based chemical adjuvant is selected from vectofusin-1, pol oxamer Fl 08, and Lentiboost™. In aspects, the method of making comprises a spinoculation step at the beginning of transduction.

[0128] In aspects, expression of at least one VMG is under the control of a drug-inducible promoter. In aspects, expression of at least two VMGs that are not the same are each under the control of separate drug-inducible promoters that are not the same. The drug-inducible promoter may be any suitable drug-inducible promoter

[0129] In aspects, the present disclosure provides a method of improving the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; the method comprising, consisting of, consisting essentially of designing or preparing the EDV to comprise at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same.

[0130] In aspects, the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant viral membrane glycoprotein (VMG) and not comprising the at least one second recombinant VMG.

[0131] In aspects, the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one second recombinant viral membrane glycoprotein (VMG) and not comprising the at least one first recombinant VMG.

[0132] The cell infection efficiency can be increased by any amount. In aspects, the cell infection efficiency is increased by more than a 1 fold change to more than a 20 fold range or any fold range between. In aspects, the cell infection efficiency is increased by more than a 1fold change. In aspects, the cell infection efficiency is increased by more than a 5 fold change. In aspects, the cell infection efficiency is increased by more than a 10 fold change. In aspects, the cell infection efficiency is increased by more than a 20 fold change.

[0133] In aspects, the first targeting molecule targets a CD3 receptor. In aspects, the first targeting molecule comprises a single-chain variable fragment (scFv) UCHT1 comprising a variable heavy chain (VH) comprising the amino acid sequence of SEQ ID NO: 27 and a variable light chain (VL) comprising of the amino acid sequence of SEQ ID NO: 26. In aspects, the second targeting molecule targets a CD4 receptor. In aspects, the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 100. In aspects, the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 72 and a VL comprising of the amino acid sequence of SEQ ID NO: 73. In aspects, the second targeting molecule targets a CD8 receptor. In aspects, the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 102. In aspects, the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 88 and a VL comprising of the amino acid sequence of SEQ ID NO: 89.

[0134] In aspects, the present disclosure provides an enveloped delivery vehicle (EDV) comprising, consisting of, consisting essentially of: (1) an envelope membrane; (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; and (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; wherein the other recombinant fusion proteinof (2) is not the same as the other recombinant fusion protein of (3); and wherein the EDV is produced using retrovirus infection.

[0135] In aspects, the retrovirus is a lentivirus. In aspects, the EDV is a lentiviral vector particle. In aspects, the lentiviral vector particle, has a diameter of 80 nm to 100 nm, e.g., 80 nm, 81 nm, 82 nm, 83 nm, 84 nm, 85 nm, 86 nm, 87 nm, 88 nm, 89 nm, 90 nm, 91 nm, 92 nm, 93 nm, 94 nm, 95 nm, 96 nm, 97 nm, 98 nm, 99 nm, 100 nm, or a diameter defined by a range of any two of the foregoing values.

[0136] In aspects, the EDV comprises (4) at least one third recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

[0137] In aspects, at least one polypeptide tag is SpyTag (SEQ ID NO: 187), SpyTag002 (SEQ ID NO: 189), SpyTag003 (SEQ ID NO: 191), Isopeptag (SEQ ID NO: 194), or SnoopTag (SEQ ID NO: 196). In aspects, at least one polypeptide catcher is SpyCatcher (SEQ ID NO: 188), SpyCatcher002 (SEQ ID NO: 190), SpyCatcher003 (SEQ ID NO: 192), KTag (SEQ ID NO: 193), pilin-C (SEQ ID NO: 195), or SnoopCatcher (SEQ ID NO: 197).

[0138] In aspects, the other recombinant fusion protein of (2) comprises a first targeting molecule and the other recombinant fusion protein of (3) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

[0139] In aspects, at least one polypeptide catcher is N-terminal to at least one targeting molecule in at least one other recombinant fusion protein. In aspects, at least one targeting molecule is N-terminal to at least one polypeptide catcher in at least one other recombinant fusion protein. In aspects, at least one other recombinant fusion protein comprises a linker between at least one polypeptide catcher and at least one targeting molecule.

[0140] In aspects, the present disclosure provides a method of generating an enveloped delivery vehicle (EDV), the method comprising: (a) transfecting or transducing a host cell with at least one expression construct encoding at least two recombinant viral membrane glycoproteins (VMGs); wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein theother recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; (b) maintaining the host cell within suitable conditions for at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (1) an envelope membrane; and (2) at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) that are incorporated into the envelope membrane; (I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; (II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and (d) covalently bonding to at least one first recombinant VMG of (c) a polypeptide catcher within another recombinant fusion protein and covalently bonding to at least one second VMG of (c) a polypeptide catcher within another recombinant fusion protein, wherein the other recombinant fusion protein covalently bound to at least one first recombinant VMG of (c) is not the same as the other recombinant fusion protein covalently bound to at least one second recombinant VMG of (c); and wherein the EDV is produced using retrovirus infection.

[0141] In aspects, the method comprises (a) transfecting or transducing a host cell with at least one second expression construct encoding at least one third recombinant VMG comprising a fusion protein comprising a fusogenic membrane glycoprotein (FMG)comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein; (b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one second expression construct of (a) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (3) at least one third recombinant VMG encoded by at least one second expression construct of (a) that is incorporated into the envelope membrane; (III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

[0142] In aspects, the present disclosure provides a method of generating an enveloped delivery vehicle (EDV), the method comprising, consisting of, consisting essentially of: (a) transfecting or transducing a host cell with: (i) at least one first expression construct encoding at least one first recombinant viral membrane glycoprotein (VMG); and (ii) at least one second expression construct encoding at least one second recombinant VMG; wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; (b) maintaining the host cell within suitable conditions for at least one first recombinant VMG encoded by at least one first expression construct of (i) to be expressed and for at least one second recombinant VMG encoded by at least one second expression construct of (ii) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (1) an envelope membrane; (2) at least one first recombinant VMG encoded by at least one first expression construct of (i) that is incorporated into the envelope membrane; and (3) at least one second recombinant VMGencoded by at least one second expression construct of (ii) that is incorporated into the envelope membrane; (I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; (II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and (d) covalently bonding to at least one first recombinant VMG of (c) a polypeptide catcher within another recombinant fusion protein and covalently bonding to at least one second VMG of (c) a polypeptide catcher within another recombinant fusion protein, wherein the other recombinant fusion protein covalently bound to at least one first recombinant VMG of (c) is not the same as the other recombinant fusion protein covalently bound to at least one second recombinant VMG of (c); and wherein the EDV is produced using retrovirus infection.

[0143] In aspects, the method comprises (a) transfecting or transducing a host cell with: (iii) at least one third expression construct encoding at least one third recombinant VMG; wherein at least one third recombinant VMG comprises a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein; (b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one third expression construct of (iii) to be expressed; and (c) collecting an EDV from the host cell, the EDV comprising: (4) at least one third recombinant VMG encoded by at least one third expression construct of (iii) that is incorporated into the envelope membrane; (III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

[0144] In aspects, the present disclosure provides a method of improving the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having (1) an envelope membrane and (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; and the method comprising, consisting of, consisting essentially of designing or preparing the EDV to comprise (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; wherein the other recombinant fusion protein of (2) is not the same as the other recombinant fusion protein of (3).

[0145] The below are certain aspects of the disclosure.

[0146] 1. An enveloped delivery vehicle (EDV), comprising:(1) an envelope membrane;(2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and(3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same.

[0147] 2 The EDV of aspect 1, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKitreceptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

[0148] 3 The EDV of aspect 1 or 2, wherein at least one targeting molecule is a ligand.

[0149] 4. The EDV of aspect 3, wherein the ligand comprises epidermal growth factor(EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

[0150] 5. The EDV of aspect 1 or 2, wherein at least one targeting molecule is an antibody or portion thereof.

[0151] 6. The EDV of aspect 5, wherein the antibody or portion thereof is a single-chain variable fragment (scFv), a nanobody, or a minibody.

[0152] 7. The EDV of aspect 6, wherein the antibody or portion thereof is a scFv.

[0153] 8. The EDV of aspect 7, wherein the scFv comprises a variable heavy chain(VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

[0154] 9. The EDV of aspect 8, wherein the VH is N-terminal to the VL.

[0155] 10. The EDV of aspect 8, wherein the VL is N-terminal to the VH.

[0156] 11. The EDV of any one of aspects 8-10, wherein the VH and VL are separated by a flexible linker.

[0157] 12. The EDV of aspect 11, wherein the flexible linker comprises SEQ ID NO: 17.

[0158] 13. The EDV of aspect 6, wherein the antibody or portion thereof is a nanobody.

[0159] 14. The EDV of aspect 13, wherein the nanobody comprises SEQ ID NO: 100,SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

[0160] 15. The EDV of aspect 6, wherein the antibody or portion thereof is a minibody.

[0161] 16. The EDV of aspect 15, wherein the minibody comprises SEQ ID NO: 104.

[0162] 17. The EDV of any one of aspects 1-16, wherein at least one FMG is N-terminal to at least one targeting molecule in at least one VMG.

[0163] 18. The EDV of any one of aspects 1-17, wherein at least one targeting molecule is N-terminal to at least one FMG in at least one VMG.

[0164] 19. The EDV of any one of aspects 1-18, wherein at least one VMG comprises a linker between at least one FMG and at least one targeting molecule.

[0165] 20. The EDV of aspect 19, wherein the linker is flexible.

[0166] 21. The EDV of aspect 20, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), or VPGVGVPGVG (SEQ ID NO: 57).

[0167] 22. The EDV of aspect 19, wherein the linker is rigid.

[0168] 23. The EDV of aspect 22, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

[0169] 24. The EDV of any one of aspects 1-23, wherein the number of VMG(s) of (2) in the envelope membrane is not the same as the number of VMG(s) of (3) in the envelope membrane.

[0170] 25. The EDV of any one of aspects 1-24, wherein the EDV comprises (4) at least one third recombinant VMG incorporated into the envelope membrane comprising a fusionprotein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule.

[0171] 26. The EDV of any one of aspect 25, wherein the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

[0172] 27. The EDV of aspect 26, wherein the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is 1 : 1 :6.

[0173] 28. The EDV of any one of aspects 1-27, wherein at least one FMG is engineered to reduce or eliminate binding to its natural receptor.

[0174] 29. The EDV of any one of aspects 1-28, wherein two or more VMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

[0175] 30. The EDV of any one of aspects 1-29, wherein at least one FMG comprises a rhabdoviral G protein.

[0176] 31. The EDV of aspect 30, wherein the rhabdoviral G protein is of a Flanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein (RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawara glycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), a Bovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), a Niakha glycoprotein (NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G).

[0177] 32. The EDV of aspect 30, wherein the rhabdoviral G protein is of a Vesiculovirus glycoprotein.

[0178] 33. The EDV of aspect 32, wherein the rhabdoviral G protein is of VesiculovirusIndiana, Vesiculovirus newjersey, Vesiculovirus carajas, or Vesiculovirus alagoas.

[0179] 34. The EDV of aspect 33, wherein the rhabdoviral G protein is of VesiculovirusIndiana (SEQ ID NO: 9).

[0180] 35. The EDV of aspect 33, wherein the rhabdoviral G protein is of Vesiculovirus newjersey (SEQ ID NO: 10).

[0181] 36. The EDV of any one of aspects 30-35, wherein the rhabdoviral G protein is engineered to have a mutation to reduce or abolish its natural receptor binding specificity.

[0182] 37. The EDV of any one of aspects 30-36, wherein the rhabdoviral G protein comprises a mutation at one or more positions corresponding to H8, K47, Y209, and K354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

[0183] 38. The EDV of aspect 36 or 37, wherein the mutation is a substitution.

[0184] 39. The EDV of any one of aspects 36-38, wherein the substitution is with a Q.

[0185] 40. The EDV of any one of aspects 36-39, wherein the mutation is a substitution at two or more positions.

[0186] 41. The EDV of any one of aspect 36 or 37, wherein the mutation is a deletion.

[0187] 42. The EDV of aspect 41, wherein the mutation is a single deletion at the position corresponding to K47 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

[0188] 43. A method of generating an enveloped delivery vehicle (EDV), the method comprising:(a) transfecting or transducing a host cell with at least one expression construct encoding at least two recombinant viral membrane glycoproteins (VMGs); wherein at least one first recombinant VMG comprises a fusion protein comprising(A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and(B) a first targeting molecule; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same;(b) maintaining the host cell within suitable conditions for at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(1) an envelope membrane; and(2) at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) that are incorporated into the envelope membrane;(I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a first targeting molecule;(II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; and wherein the first targeting molecule and the second targeting molecule are not the same.

[0189] 44. The method of aspect 43, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

[0190] 45. The method of aspect 43 or 44, wherein at least one targeting molecule is a ligand.

[0191] 46. The method of aspect 45, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

[0192] 47. The method of aspect 43 or 44, wherein at least one targeting molecule is an antibody or portion thereof.

[0193] 48. The method of aspect 47, wherein the antibody or portion thereof is a singlechain variable fragment (scFv), a nanobody, or a minibody.

[0194] 49. The method of aspect 48, wherein the antibody or portion thereof is a scFv.

[0195] 50. The method of aspect 49, wherein the scFv comprises a variable heavy chain(VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL ofSEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

[0196] 51. The method of aspect 50, wherein the VH is N-terminal to the VL.

[0197] 52. The method of aspect 50, wherein the VL is N-terminal to the VH.

[0198] 53. The method of any one of aspects 50-52, wherein the VH and VL are separated by a flexible linker.

[0199] 54. The method of aspect 53, wherein the flexible linker comprises SEQ ID NO:17.

[0200] 55. The method of aspect 48, wherein the antibody or portion thereof is a nanobody.

[0201] 56. The method of aspect 55, wherein the nanobody comprises SEQ ID NO: 100,SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

[0202] 57. The method of aspect 48, wherein the antibody or portion thereof is a minibody.

[0203] 58. The method of aspect 57, wherein the minibody comprises SEQ ID NO: 104.

[0204] 59. The method of any one of aspects 43-58, wherein at least one FMG is N- terminal to at least one targeting molecule in at least one VMG.

[0205] 60. The method of any one of aspects 43-59, wherein at least one targeting molecule is N-terminal to at least one FMG in at least one VMG

[0206] 61. The method of any one of aspects 43-60, wherein at least one VMG comprises a linker between at least one FMG and at least one targeting molecule.

[0207] 62. The method of aspect 61, wherein the linker is flexible.

[0208] 63. The method of aspect 62, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49), AAASGGSGGGGSGGGGS (SEQ ID NO: 50), GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51), GGGGSGGGGSGGGGS (SEQ ID NO: 17), GGGGSGGGGS (SEQ ID NO: 52), GGGGS (SEQ ID NO: 53), GGGGGGGG (SEQ ID NO: 54), GGGGGG (SEQ ID NO: 55), GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

[0209] 64. The method of aspect 61, wherein the linker is rigid.

[0210] 65. The method of aspect 64, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

[0211] 66. The method of any one of aspects 43-65, wherein the number of VMG(s) of(I) in the envelope membrane is not the same as the number of VMG(s) of (II) in the envelope membrane.

[0212] 67. The method of any one of aspects 43-66, comprising(a) transfecting or transducing a host cell with at least one second expression construct encoding at least one third recombinant VMG comprising a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a targeting molecule;(b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one second expression construct of (a) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(3) at least one third recombinant VMG encoded by at least one second expression construct of (a) that is incorporated into the envelope membrane;(III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule.

[0213] 68. The method of aspect 67, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

[0214] 69. The method of aspect 68, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is 1 : 1 :6.

[0215] 70. A method of generating an enveloped delivery vehicle (EDV), the method comprising:(a) transfecting or transducing a host cell with:(i) at least one first expression construct encoding at least one first recombinant viral membrane glycoprotein (VMG); and(ii) at least one second expression construct encoding at least one second recombinant VMG; wherein at least one first recombinant VMG comprises a fusion protein comprising(A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and(B) a first targeting molecule; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same;(b) maintaining the host cell within suitable conditions for at least one first recombinant VMG encoded by at least one first expression construct of (i) to be expressed and for at least one second recombinant VMG encoded by at least one second expression construct of (ii) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(1) an envelope membrane;(2) at least one first recombinant VMG encoded by at least one first expression construct of (i) that is incorporated into the envelope membrane; and(3) at least one second recombinant VMG encoded by at least one second expression construct of (ii) that is incorporated into the envelope membrane;(I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a first targeting molecule; and(II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; andwherein the first targeting molecule and the second targeting molecule are not the same.

[0216] 71. The method of aspect 70, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

[0217] 72. The method of aspect 70 or 71, wherein at least one targeting molecule is a ligand.

[0218] 73. The method of aspect 72, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

[0219] 74. The method of aspect 70 or 71, wherein at least one targeting molecule is an antibody or portion thereof.

[0220] 75. The method of aspect 74, wherein the antibody or portion thereof is a singlechain variable fragment (scFv), a nanobody, or a minibody.

[0221] 76. The method of aspect 75, wherein the antibody or portion thereof is a scFv.

[0222] 77. The method of aspect 76, wherein the scFv comprises a variable heavy chain(VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

[0223] 78. The method of aspect 77, wherein the VH is N-terminal to the VL.

[0224] 79. The method of aspect 77, wherein the VL is N-terminal to the VH.

[0225] 80. The method of any one of aspects 77-79, wherein the VH and VL are separated by a flexible linker.

[0226] 81. The method of aspect 80, wherein the flexible linker comprises SEQ ID NO:17.

[0227] 82. The method of aspect 75, wherein the antibody or portion thereof is a nanobody.

[0228] 83. The method of aspect 82, wherein the nanobody comprises SEQ ID NO: 100,SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

[0229] 84. The method of aspect 75, wherein the antibody or portion thereof is a minibody.

[0230] 85. The method of aspect 84, wherein the minibody comprises SEQ ID NO: 104.

[0231] 86. The method of any one of aspects 70-85, wherein at least one FMG is N- terminal to at least one targeting molecule in at least one VMG.

[0232] 87. The method of any one of aspects 70-86, wherein at least one targeting molecule is N-terminal to at least one FMG in at least one VMG

[0233] 88. The method of any one of aspects 70-87, wherein at least one VMG comprises a linker between at least one FMG and at least one targeting molecule.

[0234] 89. The method of aspect 88, wherein the linker is flexible.

[0235] 90. The method of aspect 89, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

[0236] 91. The method of aspect 88, wherein the linker is rigid.

[0237] 92. The method of aspect 91, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

[0238] 93. The method of any one of aspects 70-92, wherein the number of VMG(s) of(I) in the envelope membrane is not the same as the number of VMG(s) of (II) in the envelope membrane.

[0239] 94. The method of any one of aspects 70-93, comprising(a) transfecting or transducing a host cell with:(iii) at least one third expression construct encoding at least one third recombinant VMG; wherein at least one third recombinant VMG comprises a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a targeting molecule;(b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one third expression construct of (iii) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(4) at least one third recombinant VMG encoded by at least one third expression construct of (iii) that is incorporated into the envelope membrane;(III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule.

[0240] 95. The method of aspect 94, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

[0241] 96. The method of aspect 95, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is 1 : 1 :6.

[0242] 97. The method of any one of aspects 70-96, wherein the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

[0243] 98. The method of aspect 97, wherein the ratio of the first expression construct of(i) to the second expression construct of (ii) to the third expression construct of (iii) is 1 : 1 :6.

[0244] 99. The method of any one of aspects 43-98, wherein at least one FMG is engineered to reduce or eliminate binding to its natural receptor.

[0245] 100. The method of any one of aspects 43-99, wherein two or more VMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

[0246] 101. The method of any one of aspects 43-100, wherein at least one FMG comprises a rhabdoviral G protein.

[0247] 102. The method of aspect 101, wherein the rhabdoviral G protein is of aFlanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein (RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawara glycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), a Bovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), aNiakha glycoprotein (NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G).

[0248] 103. The method of aspect 101, wherein the rhabdoviral G protein is of aVesiculovirus glycoprotein.

[0249] 104. The method of aspect 101, wherein the rhabdoviral G protein is ofVesiculovirus Indiana, Vesiculovirus new jersey, Vesiculovirus carajas, or Vesiculovirus alagoas.

[0250] 105. The method of aspect 104, wherein the rhabdoviral G protein is ofVesiculovirus indiana (SEQ ID NO: 9).

[0251] 106. The method of aspect 104, wherein the rhabdoviral G protein is ofVesiculovirus new jersey (SEQ ID NO: 10).

[0252] 107. The method of any one of aspects 101-106, wherein the rhabdoviral G protein is engineered to have a mutation to reduce or abolish its natural receptor binding specificity.

[0253] 108. The method of any one of aspects 101-107, wherein the rhabdoviral G protein comprises a mutation at one or more positions corresponding to H8, K47, Y209, andK354 on the Vesiculovirus Indiana glycoprotein (SEQ ID NO: 9).

[0254] 109. The method of aspect 107 or 108, wherein the mutation is a substitution.

[0255] 110. The method of any one of aspects 107-109, wherein the substitution is with a Q.

[0256] 111. The method of any one of aspects 110, wherein the mutation is a substitution at two or more positions.

[0257] 112. The method of any one of aspect 107 or 108, wherein the mutation is a deletion.

[0258] 113. The method of aspect 112, wherein the mutation is a single deletion at the position corresponding to K47 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

[0259] 114. The method of any one of aspects 43-113, wherein transfecting or transducing a host cell comprises transfecting or transducing with at least one packaging plasmid.

[0260] 115. The method of any one of aspects 43-114, wherein expression of at least one VMG is under the control of a drug-inducible promoter.

[0261] 116. The method of aspect 115, wherein expression of at least two VMGs that are not the same are each under the control of separate drug-inducible promoters that are not the same.

[0262] 117. A method of improving the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; the method comprising designing or preparing the EDV to comprise at least one second recombinant VMG incorporated into the envelope membrane comprising a fusionprotein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same..

[0263] 118. The method of aspect 117, wherein the EDV is generated according to any one of aspects 43-116.

[0264] 119. The method of aspect 117 or 118, wherein the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant viral membrane glycoprotein (VMG) and not comprising the at least one second recombinant VMG.

[0265] 120. The method of any one of aspects 117-119, wherein the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one second recombinant viral membrane glycoprotein (VMG) and not comprising the at least one first recombinant VMG.

[0266] 121. The method of any one of aspects 117-120, wherein the cell infection efficiency is increased by more than a 1 fold change.

[0267] 122. The method of any one of aspects 117-121, wherein the cell infection efficiency is increased by more than a 5 fold change.

[0268] 123. The method of any one of aspects 117-122, wherein the cell infection efficiency is increased by more than a 10 fold change.

[0269] 124. The method of any one of aspects 117-123, wherein the cell infection efficiency is increased by more than a 20 fold change.

[0270] 125. The method of any one of aspects 117-124, wherein the first targeting molecule targets a CD3 receptor.

[0271] 126. The method of aspect 125, wherein the first targeting molecule comprises a single-chain variable fragment (scFv) UCHT1 comprising a variable heavy chain(VH) comprising the amino acid sequence of SEQ ID NO: 27 and a variable light chain (VL) comprising of the amino acid sequence of SEQ ID NO: 26

[0272] 127. The method of any one of aspects 117-126, wherein the second targeting molecule targets a CD4 receptor.

[0273] 128. The method of aspect 127, wherein the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 100.

[0274] 129. The method of aspect 127, wherein the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 72 and a VL comprising of the amino acid sequence of SEQ ID NO: 73.

[0275] 130. The method of any one of aspects 117-126, wherein the second targeting molecule targets a CD8 receptor.

[0276] 131. The method of aspect 130, wherein the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 102.

[0277] 132. The method of aspect 130, wherein the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 88 and a VL comprising of the amino acid sequence of SEQ ID NO: 89.

[0278] 133. An enveloped delivery vehicle (EDV) comprising:(1) an envelope membrane;(2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; and(3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher;wherein the other recombinant fusion protein of (2) is not the same as the other recombinant fusion protein of (3).

[0279] 134. The EDV of aspect 133, wherein the EDV is produced using retrovirus infection.

[0280] 135. The EDV of aspect 134, wherein the retrovirus is a lentivirus.

[0281] 136. The EDV of any one of aspects 133-135, wherein the EDV comprises(4) at least one third recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

[0282] 137. The EDV of any one of aspects 133-136, wherein at least one polypeptide tag is Spy Tag (SEQ ID NO: 187), SpyTag002 (SEQ ID NO: 189), SpyTag003 (SEQ ID NO: 191), Isopeptag (SEQ ID NO: 194), or SnoopTag (SEQ ID NO: 196).

[0283] 138. The EDV of any one of aspects 133-137, wherein at least one polypeptide catcher is SpyCatcher (SEQ ID NO: 188), SpyCatcher002 (SEQ ID NO: 190), SpyCatcher003 (SEQ ID NO: 192), KTag (SEQ ID NO: 193), pilin-C (SEQ ID NO: 195), or SnoopCatcher (SEQ ID NO: 197).

[0284] 139. The EDV of any one of aspects 133-138, wherein the other recombinant fusion protein of (2) comprises a first targeting molecule and the other recombinant fusion protein of (3) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

[0285] 140. The EDV of aspect 139, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

[0286] 141. The EDV of aspect 139 or 140, wherein at least one targeting molecule is a ligand.

[0287] 142. The EDV of aspect 140, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

[0288] 143. The EDV of aspect 139 or 140, wherein at least one targeting molecule is an antibody or portion thereof.

[0289] 144. The EDV of aspect 143, wherein the antibody or portion thereof is a single-chain variable fragment (scFv), a nanobody, or a minibody.

[0290] 145. The EDV of aspect 144, wherein the antibody or portion thereof is a scFv.

[0291] 146. The EDV of aspect 145, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ IDNO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH ofSEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ IDNO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

[0292] 147. The EDV of aspect 146, wherein the VH is N-terminal to the VL.

[0293] 148. The EDV of aspect 146, wherein the VL is N-terminal to the VH.

[0294] 149. The EDV of any one of aspects 146-148, wherein the VH and VL are separated by a flexible linker.

[0295] 150. The EDV of aspect 149, wherein the flexible linker comprises SEQ IDNO: 17.

[0296] 151. The EDV of aspect 144, wherein the antibody or portion thereof is a nanobody.

[0297] 152. The EDV of aspect 151, wherein the nanobody comprises SEQ ID NO:100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

[0298] 153. The EDV of aspect 144, wherein the antibody or portion thereof is a minibody.

[0299] 154. The EDV of aspect 153, wherein the minibody comprises SEQ ID NO:104.

[0300] 155. The EDV of any one of aspects 139-154, wherein at least one polypeptide catcher is N-terminal to at least one targeting molecule in at least one other recombinant fusion protein.

[0301] 156. The EDV of any one of aspects 139-155, wherein at least one targeting molecule is N-terminal to at least one polypeptide catcher in at least one other recombinant fusion protein

[0302] 157. The EDV of any one of aspects 139-156, wherein at least one other recombinant fusion protein comprises a linker between at least one polypeptide catcher and at least one targeting molecule.

[0303] 158. The EDV of aspect 157, wherein the linker is flexible.

[0304] 159. The EDV of aspect 158, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

[0305] 160. The EDV of aspect 157, wherein the linker is rigid.

[0306] 161. The EDV of aspect 160, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

[0307] 162. The EDV of any one of aspects 133-161, wherein the number ofVMG(s) of (2) in the envelope membrane is not the same as the number of VMG(s) of (3) in the envelope membrane.

[0308] 163. The EDV of any one of aspects 136-162, wherein the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 :1 to 1 :9: 1 or from 1 :1 : 1 to 9: 1 : 1.

[0309] 164. The EDV of aspect 163, wherein the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is 1 : 1 :6.

[0310] 165. The EDV of any one of aspects 133-164, wherein at least one FMG is engineered to reduce or eliminate binding to its natural receptor.

[0311] 166. The EDV of any one of aspects 133-165, wherein two or more VMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

[0312] 167. The EDV of any one of aspects 133-166, wherein at least one FMG comprises a rhabdoviral G protein.

[0313] 168. The EDV of aspect 167, wherein the rhabdoviral G protein is of aFlanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein (RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawara glycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), a Bovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), a Niakha glycoprotein (NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G).

[0314] 169. The EDV of aspect 167, wherein the rhabdoviral G protein is of aVesiculovirus glycoprotein.

[0315] 170. The EDV of aspect 169, wherein the rhabdoviral G protein is ofVesiculovirus Indiana, Vesiculovirus new jersey, Vesiculovirus carajas, or Vesiculovirus alagoas.

[0316] 171. The EDV of aspect 170, wherein the rhabdoviral G protein is ofVesiculovirus indiana (SEQ ID NO: 9).

[0317] 172. The EDV of aspect 170, wherein the rhabdoviral G protein is ofVesiculovirus new jersey (SEQ ID NO: 10).

[0318] 173. The EDV of any one of aspects 167-172, wherein the rhabdoviral G protein is engineered to have a mutation to reduce or abolish its natural receptor binding specificity.

[0319] 174. The EDV of any one of aspects 167-173, wherein the rhabdoviral G protein comprises a mutation at one or more positions corresponding to H8, K47, Y209, andK354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

[0320] 175. The EDV of aspect 173 or 174, wherein the mutation is a substitution.

[0321] 176. The EDV of any one of aspects 173-175, wherein the substitution is with a Q.

[0322] 177. The EDV of any one of aspects 173-176, wherein the mutation is a substitution at two or more positions.

[0323] 178. The EDV of any one of aspect 173 or 174, wherein the mutation is a deletion.

[0324] 179. The EDV of aspect 178, wherein the mutation is a single deletion at the position corresponding to K47 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

[0325] 180. A method of generating an enveloped delivery vehicle (EDV), the method comprising:(a) transfecting or transducing a host cell with at least one expression construct encoding at least two recombinant viral membrane glycoproteins (VMGs); wherein at least one first recombinant VMG comprises a fusion protein comprising(A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and(B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; andwherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag;(b) maintaining the host cell within suitable conditions for at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(1) an envelope membrane; and(2) at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) that are incorporated into the envelope membrane;(I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag;(II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and(d) covalently bonding to at least one first recombinant VMG of (c) a polypeptide catcher within another recombinant fusion protein and covalently bonding to at least one second VMG of (c) a polypeptide catcher within another recombinant fusion protein, wherein the other recombinant fusion protein covalently bound to at least one first recombinant VMG of (c) is not the same as the other recombinant fusion protein covalently bound to at least one second recombinant VMG of (c).

[0326] 181. The method of aspect 180, wherein the EDV is produced using retrovirus infection.

[0327] 182. The method of aspect 181, wherein the retrovirus is a lentivirus.

[0328] 183. The method of any one of aspects 180-182, comprising(a) transfecting or transducing a host cell with at least one second expression construct encoding at least one third recombinant VMG comprising a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein;(b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one second expression construct of (a) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(3) at least one third recombinant VMG encoded by at least one second expression construct of (a) that is incorporated into the envelope membrane;(III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

[0329] 184. The method of any one of aspects 180-183, wherein at least one polypeptide tag is Spy Tag (SEQ ID NO: 187), SpyTag002 (SEQ ID NO: 189), SpyTag003 (SEQ ID NO: 191), Isopeptag (SEQ ID NO: 194), or SnoopTag (SEQ ID NO: 196).

[0330] 185. The method of any one of aspects 180-184, wherein at least one polypeptide catcher is SpyCatcher (SEQ ID NO: 188), SpyCatcher002 (SEQ ID NO: 190), SpyCatcher003 (SEQ ID NO: 192), KTag (SEQ ID NO: 193), pilin-C (SEQ ID NO: 195), or SnoopCatcher (SEQ ID NO: 197).

[0331] 186. The method of any one of aspects 180-185, wherein the other recombinant fusion protein of (I) comprises a first targeting molecule and the other recombinant fusion protein of (II) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

[0332] 187. The method of aspect 186, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKitreceptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

[0333] 188. The method of aspect 186 or 187, wherein at least one targeting molecule is a ligand.

[0334] 189. The method of aspect 188, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

[0335] 190. The method of aspect 186 or 187, wherein at least one targeting molecule is an antibody or portion thereof.

[0336] 191. The method of aspect 190, wherein the antibody or portion thereof is a single-chain variable fragment (scFv), a nanobody, or a minibody.

[0337] 192. The method of aspect 191, wherein the antibody or portion thereof is a scFv.

[0338] 193. The method of aspect 192, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL ofSEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

[0339] 194. The method of aspect 193, wherein the VH is N-terminal to the VL.

[0340] 195. The method of aspect 193, wherein the VL is N-terminal to the VH.

[0341] 196. The method of any one of aspects 193-195, wherein the VH and VL are separated by a flexible linker.

[0342] 197. The method of aspect 196, wherein the flexible linker comprises SEQID NO: 17.

[0343] 198. The method of aspect 191, wherein the antibody or portion thereof is a nanobody.

[0344] 199. The method of aspect 198, wherein the nanobody comprises SEQ IDNO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

[0345] 200. The method of aspect 191, wherein the antibody or portion thereof is a minibody.

[0346] 201. The method of aspect 200, wherein the minibody comprises SEQ IDNO: 104.

[0347] 202. The method of any one of aspects 180-201, wherein at least one polypeptide catcher is N-terminal to at least one targeting molecule in at least one other recombinant fusion protein.

[0348] 203. The method of any one of aspects 180-202, wherein at least one targeting molecule is N-terminal to at least one polypeptide catcher in at least one other recombinant fusion protein

[0349] 204. The method of any one of aspects 180-203, wherein at least one other recombinant fusion protein comprises a linker between at least one polypeptide catcher and at least one targeting molecule.

[0350] 205. The method of aspect 204, wherein the linker is flexible.

[0351] 206. The method of aspect 205, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49), AAASGGSGGGGSGGGGS (SEQ ID NO: 50), GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51), GGGGSGGGGSGGGGS (SEQ ID NO: 17), GGGGSGGGGS (SEQ ID NO: 52), GGGGS (SEQ ID NO: 53), GGGGGGGG (SEQ ID NO: 54), GGGGGG (SEQ ID NO: 55), GSAGSAAGSGEF (SEQ ID NO: 56), or VPGVGVPGVG (SEQ ID NO: 57).

[0352] 207. The method of aspect 204, wherein the linker is rigid.

[0353] 208. The method of aspect 207, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

[0354] 209. The method of any one of aspects 180-208, wherein the number ofVMG(s) of (I) in the envelope membrane is not the same as the number of VMG(s) of (II) in the envelope membrane.

[0355] 210. The method of any one of aspects 183-209, wherein the ratio ofVMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 :1 to 9: 1 : 1.

[0356] 211. The method of aspect 210, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is 1 : 1 :6.

[0357] 212. A method of generating an enveloped delivery vehicle (EDV), the method comprising:(a) transfecting or transducing a host cell with:(i) at least one first expression construct encoding at least one first recombinant viral membrane glycoprotein (VMG); and(ii) at least one second expression construct encoding at least one second recombinant VMG; wherein at least one first recombinant VMG comprises a fusion protein comprising(A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and(B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag;(b) maintaining the host cell within suitable conditions for at least one first recombinant VMG encoded by at least one first expression construct of (i) to be expressed and for at least one second recombinant VMG encoded by at least one second expression construct of (ii) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(1) an envelope membrane;(2) at least one first recombinant VMG encoded by at least one first expression construct of (i) that is incorporated into the envelope membrane; and(3) at least one second recombinant VMG encoded by at least one second expression construct of (ii) that is incorporated into the envelope membrane;(I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag;(II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and(d) covalently bonding to at least one first recombinant VMG of (c) a polypeptide catcher within another recombinant fusion protein and covalently bonding to at least one second VMG of (c) a polypeptide catcher within another recombinant fusion protein, wherein the other recombinant fusion protein covalently bound to at least one first recombinant VMG of (c) is not the same as the other recombinant fusion protein covalently bound to at least one second recombinant VMG of (c).

[0358] 213. The method of aspect 212, wherein the EDV is produced using retrovirus infection.

[0359] 214. The method of aspect 213, wherein the retrovirus is a lentivirus.

[0360] 215. The method of any one of aspects 212-214, comprising(a) transfecting or transducing a host cell with:(iii) at least one third expression construct encoding at least one third recombinant VMG; wherein at least one third recombinant VMG comprises a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein;(b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one third expression construct of (iii) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(4) at least one third recombinant VMG encoded by at least one third expression construct of (iii) that is incorporated into the envelope membrane;(III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

[0361] 216. The method of any one of aspects 212-215, wherein at least one polypeptide tag is Spy Tag (SEQ ID NO: 187), SpyTag002 (SEQ ID NO: 189), SpyTag003 (SEQ ID NO: 191), Isopeptag (SEQ ID NO: 194), or SnoopTag (SEQ ID NO: 196).

[0362] 217. The method of any one of aspects 212-216, wherein at least one polypeptide catcher is SpyCatcher (SEQ ID NO: 188), SpyCatcher002 (SEQ ID NO: 190), SpyCatcher003 (SEQ ID NO: 192), KTag (SEQ ID NO: 193), pilin-C (SEQ ID NO: 195), or SnoopCatcher (SEQ ID NO: 197).

[0363] 218. The method of any one of aspects 212-217, wherein the other recombinant fusion protein of (I) comprises a first targeting molecule and the other recombinant fusion protein of (II) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

[0364] 219. The method of aspect 218, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

[0365] 220. The method of aspect 218 or 219, wherein at least one targeting molecule is a ligand.

[0366] 221. The method of aspect 220, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

[0367] 222. The method of aspect 218 or 219, wherein at least one targeting molecule is an antibody or portion thereof.

[0368] 223. The method of aspect 222, wherein the antibody or portion thereof is a single-chain variable fragment (scFv), a nanobody, or a minibody.

[0369] 224. The method of aspect 223, wherein the antibody or portion thereof is a scFv.

[0370] 225. The method of aspect 224, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL ofSEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

[0371] 226. The method of aspect 225, wherein the VH is N-terminal to the VL.

[0372] 227. The method of aspect 225, wherein the VL is N-terminal to the VH.

[0373] 228. The method of any one of aspects 225-227, wherein the VH and VL are separated by a flexible linker.

[0374] 229. The method of aspect 228, wherein the flexible linker comprises SEQID NO: 17.

[0375] 230. The method of aspect 223, wherein the antibody or portion thereof is a nanobody.

[0376] 231. The method of aspect 230, wherein the nanobody comprises SEQ IDNO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

[0377] 232. The method of aspect 223, wherein the antibody or portion thereof is a minibody.

[0378] 233. The method of aspect 232, wherein the minibody comprises SEQ IDNO: 104.

[0379] 234. The method of any one of aspects 218-233, wherein at least one polypeptide catcher is N-terminal to at least one targeting molecule in at least one other recombinant fusion protein.

[0380] 235. The method of any one of aspects 218-234, wherein at least one targeting molecule is N-terminal to at least one polypeptide catcher in at least one other recombinant fusion protein

[0381] 236. The method of any one of aspects 218-235, wherein at least one other recombinant fusion protein comprises a linker between at least one polypeptide catcher and at least one targeting molecule.

[0382] 237. The method of aspect 236, wherein the linker is flexible.

[0383] 238. The method of aspect 237, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49), AAASGGSGGGGSGGGGS (SEQ ID NO: 50), GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51), GGGGSGGGGSGGGGS (SEQ ID NO: 17), GGGGSGGGGS (SEQ ID NO: 52), GGGGS (SEQ ID NO: 53), GGGGGGGG (SEQ ID NO: 54), GGGGGG (SEQ ID NO: 55), GSAGSAAGSGEF (SEQ ID NO: 56), or VPGVGVPGVG (SEQ ID NO: 57).

[0384] 239. The method of aspect 237, wherein the linker is rigid.

[0385] 240. The method of aspect 239, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64), CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

[0386] 241. The method of any one of aspects 180-240, wherein the number ofVMG(s) of (I) in the envelope membrane is not the same as the number of VMG(s) of (II) in the envelope membrane.

[0387] 242. The method of any one of aspects 215-241, wherein the ratio ofVMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 :1 to 9: 1 : 1.

[0388] 243. The method of aspect 242, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is 1 : 1 :6.

[0389] 244. The method of any one of aspects 212-243, wherein the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is from 1 :1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

[0390] 245. The method of aspect 244, wherein the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is 1 : 1 :6.

[0391] 246. The method of any one of aspects 180-245, wherein at least one FMG is engineered to reduce or eliminate binding to its natural receptor.

[0392] 247. The method of any one of aspects 180-246, wherein two or moreVMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

[0393] 248. The method of any one of aspects 180-247, wherein at least one FMG comprises a rhabdoviral G protein.

[0394] 249. The method of aspect 248, wherein the rhabdoviral G protein is of aFlanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein (RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawaraglycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), aBovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), a Niakha glycoprotein (NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G).

[0395] 250. The method of aspect 248, wherein the rhabdoviral G protein is of aVesiculovirus glycoprotein.

[0396] 251. The method of aspect 250, wherein the rhabdoviral G protein is ofVesiculovirus Indiana, Vesiculovirus new jersey, Vesiculovirus carajas, or Vesiculovirus alagoas.

[0397] 252. The method of aspect 251, wherein the rhabdoviral G protein is ofVesiculovirus indiana (SEQ ID NO: 9).

[0398] 253. The method of aspect 251 , wherein the rhabdoviral G protein is ofVesiculovirus new jersey (SEQ ID NO: 10).

[0399] 254. The method of any one of aspects 248-253, wherein the rhabdoviral G protein is engineered to have a mutation to reduce or abolish its natural receptor binding specificity.

[0400] 255. The method of any one of aspects 248-254, wherein the rhabdoviral G protein comprises a mutation at one or more positions corresponding to H8, K47, Y209, andK354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

[0401] 256. The method of aspect 254 or 255, wherein the mutation is a substitution.

[0402] 257. The method of any one of aspects 254-256, wherein the substitution is with a Q.

[0403] 258. The method of any one of aspects 255-257, wherein the mutation is a substitution at two or more positions.

[0404] 259. The method of aspect 254 or 255, wherein the mutation is a deletion.

[0405] 260. The method of aspect 259, wherein the mutation is a single deletion at the position corresponding to K47 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

[0406] 261. The method of any one of aspects 180-260, wherein transfecting or transducing a host cell comprises transfecting or transducing with at least one packaging plasmid.

[0407] 262. The method of any one of aspects 180-261, wherein expression of at least one VMG is under the control of a drug-inducible promoter.

[0408] 263. The method of aspect 262, wherein expression of at least two VMGs that are not the same are each under the control of separate drug-inducible promoters that are not the same.264. A method of improving the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having (1) an envelope membrane and (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; and the method comprising designing or preparing the EDV to comprise (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; wherein the other recombinant fusion protein of (2) is not the same as the other recombinant fusion protein of (3).

[0409] 265. The method of aspect 264, wherein the EDV is generated according to any one of aspects 180-263.

[0410] 266. The method of aspect 264 or 265, wherein the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV)designed to have or having an envelope membrane and the at least one first recombinant viral membrane glycoprotein (VMG) and not comprising the at least one second recombinant VMG.

[0411] 267. The method of any one of aspects 264-266, wherein the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one second recombinant viral membrane glycoprotein (VMG) and not comprising the at least one first recombinant VMG.

[0412] 268. The method of any one of aspects 264-267, wherein the cell infection efficiency is increased by more than a 1 fold change.

[0413] 269. The method of any one of aspects 264-268, wherein the cell infection efficiency is increased by more than a 5 fold change.

[0414] 270. The method of any one of aspects 264-269, wherein the cell infection efficiency is increased by more than a 10 fold change.

[0415] 271. The method of any one of aspects 264-270, wherein the cell infection efficiency is increased by more than a 20 fold change.

[0416] 272. The method of any one of aspects 180-185, wherein the other recombinant fusion protein of (2) comprises a first targeting molecule and the other recombinant fusion protein of (3) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

[0417] 273. The method of aspect 272, wherein the first targeting molecule targets a CD3 receptor.

[0418] 274. The method of aspect 273, wherein the first targeting molecule comprises a single-chain variable fragment (scFv) UCHT1 comprising a variable heavy chain (VH) comprising the amino acid sequence of SEQ ID NO: 27 and a variable light chain (VL) comprising of the amino acid sequence of SEQ ID NO: 26

[0419] 275. The method of any one of aspects 272-274, wherein the second targeting molecule targets a CD4 receptor.

[0420] 276. The method of aspect 275, wherein the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 100.

[0421] 277. The method of aspect 275, wherein the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 72 and a VL comprising of the amino acid sequence of SEQ ID NO: 73.

[0422] 278. The method of any one of aspects 272-274, wherein the second targeting molecule targets a CD8 receptor.

[0423] 279. The method of aspect 278, wherein the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 102.

[0424] 280. The method of aspect 278, wherein the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 88 and a VL comprising of the amino acid sequence of SEQ ID NO: 89.

[0425] It shall be noted that the preceding are merely examples of aspects of the disclosure. Other exemplary aspects are apparent from the entirety of the description herein. It will also be understood by one of ordinary skill in the art that each of these aspects may be used in various combinations with the other aspects provided herein.

[0426] The following examples further illustrate aspects of the disclosure, but, of course, should not be construed as in any way limiting its scope.Example 1

[0427] This example demonstrates the targeting specificity of lentivirus particles pseudotyped with recombinant fusion proteins of LDLR blinded VSV-G fused to a cKit receptor targeting molecule and recombinant fusion proteins of LDLR blinded VSV-G fused to thrombopoietin receptor (TPO-R) targeting molecule.

[0428] Experiments were performed in order to test the targeting specificity and efficacy of lentivirus pseudotyped with a recombinant fusion protein of a cKit receptor targeting molecule, SCF ligand, fused to a LDLR blinded VSV-G, VSV-G-AK47, via a 19 amino acid linker molecule (hSCF-19aaL(F)-VSV-G-AK47) and a recombinant fusion protein of a TPO- R targeting molecule, Romiplostim with (G)x8 and (G)x5 spacer, fused to VSV-G-AK47 via a 19 amino acid linker molecule (Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)- VS V-G- AK47) (FIG. 1). Using this multiplexed trimer approach packaging cells were transfected with envelope plasmids encoding a recombinant fusion protein of Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)- VS V-G-AK47 and hSCF-19aaL(F)-VSV-G-AK47 at ratios from 1 :4 to 4: 1 as shown in Table 1. Envelope plasmids encoding a recombinant fusion protein ofVSV G-AK47 were also used as controls. HEK-293 packaging cells were cultured in 15 cm dishes and transfected with transfer plasmid containing a GFP expression cassette, packaging plasmid, and one or more envelope plasmid (FIG. 2). For each condition shown in Table 1 6000 ng total of envelope plasmid was used. 72 hours post-transfection, virus supernatant was collected and concentrated, and 5e7 lentiviral particles were loaded per well for the virion pellets and 10 ug of protein were loaded per well for the cell lysate and were then subjected to western blotting with anti-VSV-G antibody, anti-SCF antibody, anti-TPO antibody, and anti-p24 antibody (FIGs. 3 A-3D). These results showed that the lentiviral particles display the mixed population of chimeric and non-chimeric blinded VSV G-AK47 glycoproteins, in the appropriate constructs. These results showed that all the lentiviral particles prepared with constructs encoding SCF showed bands for human SCF. These results also show no TPO protein bands are present because the constructs encode a peptide targeted to cMpl, but not the full-length ligand, which is what is bound by the TPO antibody. Further, the cells transfected for lentivirus production expressed the chimeric and non-chimeric blinded VSV G-AK47 glycoproteins, appropriately. Human SCF was also expressed in cells with constructs encoding SCF and full length TPO was not expressed in cells with constructs encoding a peptide targeted to cMpl.

[0429] The collected lentiviral particles were then used at a concentration of 1000 lentiviral particles per cell to transduce K562 parental cells (K562), K562 cells expressing the human thrombopoietin receptor (hTPO-R) which is also known as myeloproliferative leukemia protein (cMpl) (K562-hcMpl), K562 cells expressing human cKit (K562-hcKit), and K562 cells expressing both hcMpl and hcKit (K562-hcMpl-hcKit). 72 hours after transduction cells were imaged on CELIGO machines using a 15 ms exposure (FIGs. 4A- 4D). These results showed that while lentivirus particles pseudotyped with a 1 :3 ratio of hSCF-19aaL(F)-VSV-G-AK47 : VSV-G-AK47 or Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)-VSV-G-AK47 : VSV-G-AK47 transduced K562 cells expressing their respective receptors as shown in FIGs. 4A-4B, lentiviruses pseudotyped with a combination of the hSCF-19aaL(F)-VSV-G-AK47 and Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)-VSV-G- AK47 without the additional non-chimeric VSV-G-AK47 did not show transduction. These results suggest that a combination of recombinant blinded VSV-G with a targeting molecule (chimeric VSV-G) and recombinant blinded VSV-G without a targeting molecule (non- chimeric VSV-G) may improve effective retargeting of lentivirus particles or other membraned vehicles.Example 2

[0430] This example demonstrates the targeting specificity of lentivirus particles pseudotyped with recombinant fusion proteins of LDLR blinded VSV-G alone, recombinant fusion proteins of LDLR blinded VSV-G fused to a cKit receptor targeting molecule, and recombinant fusion proteins of LDLR blinded VSV-G fused to a thrombopoietin receptor (TPO-R) targeting molecule.

[0431] In order to improve the multiplex targeting of the constructs used in Example 1, experiments were performed using a combination of envelope plasmids encoding VSV-G- AK47, hSCF-19aaL(F)-VSV-G-AK47, and Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)- VSV-G-AK47 (FIG. 5). Using this multiplexed mixed trimer approach packaging cells were transfected with envelope plasmids encoding a recombinant fusion protein of Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)-VSV-G-AK47, hSCF-19aaL(F)-VSV-G-AK47, and VSV-G- AK47 at ratios from 1 : 1 : 1 to 1 :1 :6 (0.5:0.5:3) as shown in Table 1. HEK-293 packaging cells were cultured in 15 cm dishes and transfected with transfer plasmid containing a GFP expression cassette, packaging plasmid, and one or more envelope plasmid. For each condition shown in Table 1 6000 ng total of envelope plasmid was used. 72 hours posttransfection, virus supernatant was collected and concentrated, and 5e7 lentiviral particles per well of the virion pellets and 10 pg of protein of the cell lysate per well were then subjected to western blotting with anti-VSV-G antibody, anti-SCF antibody, anti-TPO antibody, and anti-p24 antibody (FIGs. 6A-6B). These results showed that all the virions and transfected cells used for lentivirus production, expressed chimeric and non-chimeric blinded VSV-G- AK47 and all the virions and transfected cells used for lentivirus production with a hSCF- 19aaL(F)-VSV-G-AK47 encoding plasmid additionally expressed SCF.

[0432] The collected lentiviral particles were then used at a concentration of 1000 lentiviral particles per cell to transduce K562-hcMpl cells, K562-hcKit cells, and K562- hcMpl-hcKit cells. 72 hours after transduction K562 parental cells and K562-hcMpl-hcKit cells (FIGs. 7A-7B) and K562 parental cells, K562-hcMpl cells, and K562-hcKit cells (FIGs. 9A-9F) were imaged on CELIGO machines using a 15 ms exposure (FIGs. 7A-7B). These results were quantified and the percentage of GFP positive (GFP+) cells transduced was measured (FIGs. 8 and 10). The results for the K562 parental cells and K562-hcMpl-hcKit cells showed that lentivirus particles pseudotyped with a recombinant protein of Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)-VSV-G-AK47, hSCF-19aaL(F)-VSV-G-AK47, and VSV-G-AK47 at ratios of 1 : 1 : 1 and 1 : 1 :6 (0.5:0.5:3) were able to effectively transduce cells expressing receptors for both of the targeting molecules (FIG. 8). These results suggest that a combination of recombinant blinded VSV-G with a targeting molecule and recombinant blinded VSV-G without a targeting molecule increases effective retargeting of lentivirus particles or other membraned vehicles. The results for the K562 parental cells, K562-hcMpl cells, and K562-hcKit cells showed that lentivirus particles pseudotyped with a recombinant protein of Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)- VS V-G-AK47, hSCF-19aaL(F)- VSV-G-AK47, and VSV-G- AK47 at ratios of 1 : 1 :1 and 1 : 1 :6 (0.5:0.5:3) were able to effectively transduce cells expressing only one of the targeting molecules (FIG. 10).

[0433] 72 hours after transduction K562 parental cells, K562-hcMpl cells, and K562- hcKit cells underwent flow cytometry to measure percent of GFP+ and the results were quantified in histograms (FIGs. 11 A-l 1C). These results also demonstrated that lentivirus particles pseudotyped with a recombinant protein of Romiplostim (G)x8 w (G)x5 spacer- 19aaL(F)-VSV-G-AK47, hSCF-19aaL(F)-VSV-G-AK47, and VSV-G-AK47 at ratios of 1 : 1 : 1 and 1 : 1 :6 (0.5:0.5:3) were able to effectively transduce cells expressing only one of the targeting molecules. These results suggest that the addition of non-chimeric recombinant protein of blinded VSV-G without a targeting molecule to chimeric recombinant proteins of blinded VSV-G with a targeting molecule using the multiplexed mixed trimer approach improves the retargeting of pseudotyped lentivirus particles or other membraned vehicles compared to those using the multiplexed trimer approach with only chimeric recombinant proteins of blinded VSV-G with a targeting molecule and no non-chimeric recombinant protein of blinded VSV-G.Example 3

[0434] This example demonstrates the targeting specificity of lentivirus pseudotyped with mixed and multiplexed trimers of LDLR blinded VSV-G and recombinant fusion proteins of LDLR blinded VSV-G fused to human anti-cKit and / or hTPO-R targeting molecules in bone marrow derived human CD34+ cells.

[0435] Experiments were performed to test the targeting specificity and efficacy of lentivirus containing a GFP cassette (SEQ ID NO: 106) and pseudotyped using a mixed trimer approach at a ratio of 1 :3, 1 :5, 1 :7, or 1 : 11 with a recombinant fusion protein of a cKit targeting molecule (hSCF) (SEQ ID NO: 28) or a hTPO-R targeting molecule (Romiplostim) (SEQ ID NO: 182) targeting molecule fused to a LDLR blinded VSV-G (VSV-G-QQQ)(SEQ ID NO: 14) and blinded VSV-G (VSV-G-QQQ) (SEQ ID NO: 14) or pseudotyped using a multiplexed mixed trimer approach at a ratio of 0.5:0.5:3 with a recombinant fusion protein of a cKit targeting molecule (hSCF) (SEQ ID NO: 28) fused to a LDLR blinded VSV-G (VSV-G-QQQ) (SEQ ID NO: 14), a recombinant fusion protein of a TPO R targeting molecule (Romiplostim) (SEQ ID NO: 182) fused to a LDLR blinded VSV-G (VSV-G- QQQ) (SEQ ID NO: 14), and blinded VSV-G (VSV-G-QQQ) (SEQ ID NO: 14) in bone marrow derived human CD34+ cells additional experiments with additional modifications to the culturing conditions. 4e4 CD34+ cells were thawed and initially expanded in 100 pL SFEM II media alone (Condition 1) or supplemented with rhTPO, rhFlt3L, and rhIL6 cytokines (Condition 2) and on day 1 transduced with 1E9 lentiviral particles, as determined by p24 ELISA for each lentivirus. On day 2, an additional 100 pL of SFEM II media supplemented with either rhSCF and rhTPO (Condition 1) or rhSCF, rhTPO, rhFlt3L, and rhIL6 (Condition 2) was added to the culture (FIG. 12. On day 4 the CD34+ cells underwent analysis by fluorescent imaging with Nikon microscope and flow cytometry for eGFP expression (FIGS. 13A-13F).

[0436] The flow cytometry results showed that the CD34+ cells treated with lentivirus pseudotyped with the 1 :3 to 1 : 11 ratio mix of recombinant hSCF-VSV-G-QQQ and VSV-G- QQQ had comparable levels of transduction, approximately 4%-7% in Condition 1 and approximately 6%-9% in Condition 2 (FIG. 14). These results further support the efficacy of the mixed trimer approach and suggest that the presence of certain cytokines may inhibit transduction. The CD34+ cells treated with lentivirus pseudotyped with a 1 :3 ratio mix of recombinant Romiplostim fused to VSV-G-QQQ and VSV-G-QQQ (1 :3 hTPO Rom. : G- QQQ) showed low but detectable levels of transduction in both conditions with higher levels in Condition 2. The CD34+ cells treated with lentivirus pseudotyped with a multiplexed 0.5:0.5:3 ratio mix of recombinant hSCF- fused to VSV-G-QQQ, recombinant Romiplostim fused to VSV-G-QQQ or an empty vector control of pcDNA3.1, and VSV-G-QQQ showed similar levels of transduction of approximately 5% in Condition 1 and approximately 6% in Condition 2.Example 4

[0437] This example demonstrates the receptor levels of T-cell derived receptor cell lines. Jurkat cells and Sup-Tl cells are T-cell derived receptor cell lines. To better understand whatreceptors are expressed in these cell lines to test multiplex targeting of cells the levels of CD3 receptor, CD4 receptor, CD7 receptor, and CD8 receptor were measured.

[0438] Jurkat cells and Sup-Tl cells underwent flow cytometry using fluorescently labeled antibodies to measure levels of CD3 receptor, CD4 receptor, CD7 receptor, and CD8 receptor (FIGs. 15A-15D). These results showed that Jurkat cells showed higher CD3 receptor levels than Sup-Tl cells, Sup-Tl cells showed higher CD4 and CD8 receptor levels than Jurkat cells, and both Jurkat and Sup-Tl cells showed similar levels of CD7 receptor. A table summarizing the levels of CD3, CD4, and CD8 expression of Jurkat and Sup-Tl cells as well as other cell types used in the Examples is shown in Table 10. In Table 10 ★★★ indicates high expression, ★★ indicates moderate expression, ★ indicates low expression, and ☆ indicates negative / undetectable expression.Table 10

[0439] Based on these results additional experiments were designed to test retargeting lentiviral particles using multiplexing mixed trimers of recombinant receptor blinded VSV-G proteins fused with targeting molecules against CD3, CD4, and CD8 receptors.Example 5

[0440] This example demonstrates the development of expression vectors encoding recombinant receptor-blinded VSV-G proteins fused to CD4 receptor targeting molecules and the targeting specificity of lentivirus particles pseudotyped with these recombinant fusion proteins using the mixed trimer approach.

[0441] Constructs were designed using a pCG-4MCl 1 expression vector with sequences encoding a recombinant protein of receptor blinded VSV-G with either a single deletion of K47 (VSV-G-AK47) (SEQ ID NO: 15) or a triple substitution of K47Q+R354Q+Y209Q (VSV-G-QQQ) (SEQ ID NO: 14) with a CD4 receptor targeting molecule linked N-terminal via an IgGl linker (IgGILink) (SEQ ID NO: 65) and with an N-terminal VSV-G signaling peptide (SP) (SEQ ID NO: 35) (FIG 16).

[0442] Using this mixed trimer approach packaging cells were transfected with envelope plasmids encoding a recombinant fusion protein of a blinded VSV-G fused to a nanobody (NB) or scFv targeted against the CD4 receptor and the same blinded VSV-G at a ratio of 1 :3 as shown in Table 3. Envelope plasmids encoding a recombinant fusion protein of VSV G- WT and 1 :3 ratio of UCHT1 -VSV-G- AK47 : VSV-G-AK47 were also used as controls. Lentivirus particles containing a GFP expression cassette and pseudotyped with the recombinant proteins shown in Table 3 were prepared as described in previous Examples. 72 hours post-transfection, virus supernatant was collected and concentrated. The collected lentivirus particles were titered using p24 ELISA and quantified as shown in Table 3. The cell lysate and virion pellets were subjected to western blotting with anti-VSV-G antibody and anti-p24 antibody or anti-GAPDH antibody (FIGs. 17A-17B). The western blots were quantified and based on the size of the bands of VSV-G and VSV-G fused to a targeting molecule the percentage of VSV-G without a targeting molecule (Non-Chimeric VSV-G) and the percentage of VSV-G with a targeting molecule (Chimeric VSV-G) was calculated (FIGs. 17C-17D).

[0443] The collected lentiviral particles were then used at a concentration of 1000 lentiviral particles per cell to transduce Jurkat, Sup-Tl, Nalm6, and K562 cells that were seeded at 50000 cells per well and transduced with 1000 lentiviral particles per cell and centrifuged at 2000 RPM for 30 minutes at 4 °C. 72 hours post transduction plates were collected and fluorescence images were taken by Nikon microscope with lOx objective lens at an exposure of 100 ms (FIGs. 18A-18F). Additional fluorescent images were taken byCELIGO for cytometry measurements of the transduced cells (FIGs. 19A-19F). These results were quantified and the number of GFP+ cells transduced was measured (FIG. 20). These results showed that the lentiviruses pseudotyped with a 1 :3 ratio of blinded VSV-G with a CD4 receptor targeting molecule and blinded VSV-G was able to effectively transduce more CD4 expressing Jurkat and Sup-Tl cells than Nalm6 cells which do not express CD4. Based on these results NB#10-VSV-G-QQQ, NB#10-VSV-G-AK47, and scFv#9-VSV-G-AK47 recombinant proteins were selected for additional experiments to test multiplexing.Example 6

[0444] This example demonstrates the targeting specificity of lentivirus particles pseudotyped using the multiplexed mixed trimer approach with recombinant fusion proteins of LDLR blinded VSV-G alone, recombinant fusion proteins of LDLR blinded VSV-G fused to a CD3 receptor targeting molecule, and recombinant fusion proteins of LDLR blinded VSV-G fused to a CD4 receptor targeting molecule.

[0445] Using this multiplexed mixed trimer approach packaging cells were transfected with envelope plasmids encoding a recombinant fusion protein of a blinded VSV-G fused to a scFv targeted against the CD3 receptor, a blinded VSV-G fused to a nanobody (NB) or scFv targeted against the CD4 receptor, and the same blinded VSV-G at a ratio of 1 : 1 :6 (0.5:0.5:3) as shown in Table 4. Envelope plasmids encoding a recombinant fusion protein of VSV G- WT and 1 :3 ratio of UCHT1 -VSV-G- AK47 : VSV-G-AK47 were also used as controls. Lentivirus particles containing a GFP expression cassette and pseudotyped with the recombinant proteins shown in Table 4 were prepared as described in previous Examples. 72 hours post-transfection, virus supernatant was collected and concentrated. The collected lentivirus particles were titered using p24 ELISA and quantified as shown in Table 4. The cell lysate and virion pellets were subjected to western blotting with anti-VSV-G antibody and anti-p24 antibody (FIGs. 21 A-21B). The western blots were quantified and based on the size of the bands of VSV-G and VSV-G fused to a targeting molecule the percentage of VSV-G without a targeting molecule (Non-Chimeric VSV-G) and the percentage of VSV-G with a targeting molecule (Chimeric VSV-G) was calculated (FIGs. 21C-21D). The two bands shown in a black box observed in the VSV-G staining for the lentivirus prepared using the multiplexed mixed trimer approach with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G- AK47 : NB#10-VSV-G-AK47 : VSV-G-AK47 indicated the presence of recombinant fusion proteins of UCHT1 -VSV-G- AK47 and NB#10-VSV-G-AK47 in addition to the VSV-G-AK47 without a targeting molecule. The size of the UCHT1-VSV-G-AK47 band and the scFv#9-VSV-G-AK47 band were very similar in size such that distinct bands were not able to be resolved in the lentivirus prepared using the multiplexed mixed trimer approach with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : scFv#10-VSV-G-AK47 : VSV-G-AK47. These results suggest that lentivirus particles produced using the multiplexed mixed trimer approach can express multiple recombinant VSV-G proteins with different targeting molecules.

[0446] The collected lentiviral particles were then used at a concentration of 1000 lentiviral particles per cell to transduce Jurkat, Sup-Tl, Nalm6, and K562 cells that were seeded at 50000 cells per well and transduced with 1000 lentiviral particles per cell and either not centrifuged or centrifuged at 2000 RPM for 30 minutes at 4 °C. Centrifugation improves contact between virus and cells and was tested to determine if transduction efficiency was improved. 72 hours post transduction plates were collected and fluorescence images were taken by Nikon microscope with lOx objective lens at an exposure of 100 ms for the noncentrifuged cells (FIGS. 22A-22D) and the centrifuged cells (FIGs. 22E-22H). Additional fluorescent images were taken by CELIGO for cytometry measurements of the transduced non-centrifuged cells (FIGS. 23A-23D) and the centrifuged cells (FIGs. 23E-23H). These results were quantified and the number of GFP+ cells transduced was measured (FIGs. 24A- 24B). These results showed that the centrifuged cells showed enhanced transduction compared to non-centrifuged cells. These results were quantified and the number of GFP+ cells transduced was measured (FIG. 24A-24B). The fold change in the number of GFP+ Sup-Tl, Jurkat TCR-KO, Jurkat, and Nalm6 and K562 cells transduced with multiplexed lentivirus particles pseudotyped with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G- AK47 : NB#10-VSV-G-AK47 : VSV-G-AK47 (Dual-1) or UCHT1- VSV-G- AK47 : scFv#9-VSV-G- AK47 : VSV-G-AK47 (Dual-2) over the same cells transduced with a single targeting molecule lentivirus pseudotyped with a 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47 (aCD3), NB#10-G-AK47 : VSV-G-AK47 (aCD4-l), or scFv#9- VSV-G-AK47 : VSV-G- AK47 (aCD4-2) is shown in Figures (25A-25B). These results showed that in the non- centrifuged condition there was over a 10 fold increase in Jurkat TCR KO cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : NB#10-VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with UCHT1-VSV-G-AK47 : VSV-G-AK47, an approximately 8 fold increase in Sup-Tl cells transduced by lentiviruses prepared using the multiplex mixed trimerapproach with UCHT1-VSV-G-AK47 : NB#10-VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with NB#10-VSV-G-AK47 : VSV-G- AK47, and approximately 20 fold increase in Sup-Tl cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : scFv#9- VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with scFv#9-VSV-G-AK47 : VSV-G-AK47 (FIG. 25A). These results showed that in the centrifuged condition there was an approximately 3-8 fold increase in Jurkat TCR KO cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : NB#10-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv#9-VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with UCHT1-VSV-G-AK47 : VSV-G-AK47, an approximately 4 fold increase in Sup-Tl cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : NB#10-VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with NB#10-VSV-G-AK47 : VSV-G- AK47, and an approximately 8 fold increase in Sup-Tl cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : scFv#9- VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with scFv#9-VSV-G-AK47 : VSV-G-AK47 (FIG. 25B).

[0447] These results suggest that the multiplexing mixed trimer approach can be used to prepare lentiviral particles and other membraned vehicles that are targeted to specific cell populations expressing receptors corresponding to the targeting molecules on the recombinant fusion protein.Example 7

[0448] This example demonstrates the development of expression vectors encoding recombinant receptor-blinded VSV-G proteins fused to CD8 receptor targeting molecules and the targeting specificity of lentivirus particles pseudotyped with these recombinant fusion proteins using the mixed trimer approach.

[0449] Constructs were designed using a pCG-4MCl 1 expression vector with sequences encoding a recombinant protein of VSV-G-AK47 (SEQ ID NO: 15) or VSV-G-QQQ (SEQ ID NO: 14) with a CD8 receptor targeting molecule linked N-terminal via an IgGl linker (IgGILink) (SEQ ID NO: 65) and with an N-terminal VSV-G signaling peptide (SP) (SEQ ID NO: 35) (FIG. 26).

[0450] Using this mixed trimer approach packaging cells were transfected with envelope plasmids encoding a recombinant fusion protein of a blinded VSV-G fused to a nanobody (NB), minibody, or scFv targeted against the CD8 receptor and the same blinded VSV-G at a ratio of 1 :3 as shown in Table 5. Envelope plasmids encoding a recombinant fusion protein of VSV G-WT and 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47 were also used as controls. Lentivirus particles containing a GFP expression cassette and pseudotyped with the recombinant proteins shown in Table 5 were prepared as described in previous Examples. 72 hours post-transfection, virus supernatant was collected and concentrated. The collected lentivirus particles were titered using p24 ELISA and quantified as shown in Table 5. The cell lysate and virion pellets were subjected to western blotting with anti-VSV-G antibody and anti-p24 antibody or anti-GAPDH antibody (FIGs. 27A-27B). The western blots were quantified and based on the size of the bands of VSV-G and VSV-G fused to a targeting molecule the percentage of VSV-G without a targeting molecule (Non-Chimeric VSV-G) and the percentage of VSV-G with a targeting molecule (Chimeric VSV-G) was calculated (FIGs. 27C-27D).

[0451] The collected lentiviral particles were then used at a concentration of 1000 lentiviral particles per cell to transduce Jurkat, Jurkat LDL-R KO, Jurkat TCR KO, Sup-Tl, and Nalm6 cells that were seeded at 50000 cells per well and transduced with 1000 lentiviral particles per cell and centrifuged at 2000 RPM for 30 minutes at 4 °C. 72 hours post transduction plates were collected and fluorescence images were taken by Nikon microscope with lOx objective lens at an exposure of 100 ms (FIGs. 28A-28L). Additional fluorescent images were taken by CELIGO for cytometry measurements of the transduced cells (FIGs. 29A-29R). These results were quantified and the number of GFP+ cells transduced was measured (FIGs. 30A-30B). These results showed that the lentiviruses pseudotyped with a 1 :3 ratio of blinded VSV-G with a CD8 receptor targeting molecule and blinded VSV-G was able to effectively transduce more CD8 expressing Jurkat and Sup-Tl cells than Nalm6 cells which do not express CD8. Based on these results scFv#48-VSV-G-QQQ, scFv#48-VSV-G- AK47, and NB#28-VSV-G-AK47 recombinant proteins were selected for additional experiments to test the multiplexing mixed trimer approach.Example 8

[0452] This example demonstrates the targeting specificity of lentivirus particles pseudotyped using the multiplexed mixed trimer approach with recombinant fusion proteins of LDLR blinded VSV-G alone, recombinant fusion proteins of LDLR blinded VSV-G fused to a CD3 receptor targeting molecule, and recombinant fusion proteins of LDLR blinded VSV-G fused to a CD8 receptor targeting molecule.

[0453] Using this multiplexed mixed trimer approach packaging cells were transfected with envelope plasmids encoding a recombinant fusion protein of a blinded VSV-G fused to a scFv targeted against the CD3 receptor, a blinded VSV-G fused to a nanobody (NB), minibody, or scFv targeted against the CD8 receptor, and the same blinded VSV-G at a ratio of 1 : 1 :6 (0.5:0.5:3) as shown in Table 6. Envelope plasmids encoding a recombinant fusion protein of VSV G-WT and 1 :3 ratio of UCHT1- VSV-G- AK47 : VSV-G-AK47 were also used as controls. Lentivirus particles containing a GFP expression cassette and pseudotyped with the recombinant proteins shown in Table 6 were prepared as described in previous Examples. 72 hours post-transfection, virus supernatant was collected and concentrated. The collected lentivirus particles were titered using p24 ELISA and quantified as shown in Table 6. The cell lysate and virion pellets were subjected to western blotting with anti-VSV-G antibody and anti-p24 antibody (FIGs. 31 A- 3 IB). The two bands shown in a black box observed in the VSV-G staining for the virion particles prepared using the multiplexed mixed trimer approach with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1 -VSV-G- AK47 : NB#28-VSV-G-AK47 : VSV-G-AK47 indicated the presence of recombinant fusion proteins of UCHT1-VSV-G- AK47 and NB#28-VSV-G-AK47 in addition to the VSV-G-AK47 without a targeting molecule. The size of the UCHT1-VSV-G-AK47 band and the scFv#48-VSV-G-AK47 band were very similar in size such that distinct bands were not able to be resolved in the lentivirus prepared using the multiplexed mixed trimer approach with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-QQQ : scFv#48-VSV-G-QQQ : VSV-G-QQQ. These results suggest that lentivirus particles produced using the multiplexed mixed trimer approach can express multiple recombinant VSV-G proteins with different targeting molecules.

[0454] The collected lentiviral particles were then used at a concentration of 1000 lentiviral particles per cell to transduce Jurkat, Jurkat LDL-R KO, Jurkat TCR KO, Sup-Tl, and Nalm6 cells that were seeded at 50000 cells per well and transduced with 1000 lentiviralparticles per cell and either not centrifuged or centrifuged at 2000 RPM for 30 minutes at 4 °C. Centrifugation improves contact between virus and cells and was tested to determine if transduction efficiency was improved. 72 hours post transduction plates were collected and fluorescence images were taken by Nikon microscope with lOx objective lens at an exposure of 100 ms for the non-centrifuged cells (FIGS. 32A-32F) and the centrifuged cells (FIGs. 32G-32L). Additional fluorescent images were taken by CELIGO for cytometry measurements of the transduced non-centrifuged cells (FIGS. 33A-33F) and the centrifuged cells (FIGs. 33G-33L). These results were quantified and the number of GFP+ cells transduced was measured (FIGs. 34A-34B). These results showed that the centrifuged cells showed enhanced transduction compared to non-centrifuged cells. The fold change in the number of GFP+ Sup-Tl, Jurkat TCR-KO, Jurkat, and Nalm6 and K562 cells transduced with multiplexed lentivirus particles pseudotyped with a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV-G-AK47 (Dual-1) or UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47 (Dual-2) over the same cells transduced with a single targeting molecule lentivirus pseudotyped with a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV- G-AK47 (aCD3), NB#28-VSV-G-AK47 : VSV-G-AK47 (aCD8-l), or scFv#48-VSV-G- AK47 : VSV-G-AK47 (aCD8-2) is shown in Figures (34C-34D). These results showed that in the non-centrifuged condition there was an approximately 10 to 18 fold increase in Jurkat transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1- VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv#48- VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with NB#28-VSV-G-AK47 : VSV-G-AK47 or scFv#48-VSV-G-AK47 : VSV-G- AK47 UCHT1-VSV-G-AK47 : VSV-G-AK47, an approximately 4 to 7 fold increase in Sup- Tl cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : NB#10-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with UCHT1- VS V-G-AK47 : scFv#9-VSV-G-AK47 : VSV-G-AK47, and an approximately 10 fold increase in Sup-Tl cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV- G-AK47 compared to lentiviruses prepared with the mixed trimer approach with NB#28- VSV-G-AK47 : VSV-G-AK47 (FIG. 34C). These results showed that in the centrifuged condition there was an approximately an approximately 5 to 18 fold increase in Jurkat transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv#48- VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with NB#28-VSV-G-AK47 : VSV-G-AK47 or scFv#48-VSV-G-AK47 : VSV-G- AK47 UCHT1-VSV-G-AK47 : VSV-G-AK47, an approximately 5 to 8 fold increase in Sup- T1 cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : NB#10-VSV-G-AK47 : VSV-G-AK47 or UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47 compared to lentiviruses prepared with the mixed trimer approach with UCHT1- VS V-G-AK47 : scFv#9-VSV-G-AK47 : VSV-G-AK47, and an approximately 5 fold increase in Sup-Tl cells transduced by lentiviruses prepared using the multiplex mixed trimer approach with UCHT1-VSV-G-AK47 : NB#28-VSV-G-AK47 : VSV- G-AK47 compared to lentiviruses prepared with the mixed trimer approach with NB#28- VSV-G-AK47 : VSV-G-AK47 (FIG. 34D).

[0455] These results suggest that the multiplexing mixed trimer approach can be used to prepare lentiviral particles and other membraned vehicles that are targeted to specific cell populations expressing receptors corresponding to the targeting molecules on the recombinant fusion protein.Example 9

[0456] This example demonstrates the targeting specificity of lentivirus particles pseudotyped using the multiplexed mixed trimer approach with recombinant fusion proteins of LDLR blinded VSV-G alone, recombinant fusion proteins of LDLR blinded VSV-G fused to a CD3 receptor targeting molecule, and recombinant fusion proteins of LDLR blinded VSV-G fused to a CD8 receptor targeting molecule in human peripheral blood mononuclear cells (PBMCs).

[0457] To further test the efficacy of the multiplexing mixed trimer approach humanPBMCs were given a mock treatment or transduced with lentivirus particles pseudotyped with a recombinant VSV-G-WT or a 1 :3 ratio of UCHT1 -VSV-G- AK47 : VSV-G-AK47, UCHT1-VSV-G-QQQ : VSV-G-QQQ, NB#28-VSV-G-AK47 : VSV-G-AK47,scFv#48-VSV- G-AK47 : VSV-G-AK47, orscFv#48-VSV-G-QQQ : VSV-G-QQQ, or a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1- VSV-G- AK47 :NB#28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, UCHT1 -VSV-G-QQQ :scFv#48-VSV-G-QQQ : VSV-G-QQQ, as shown in Table 6. Flow cytometry was then performed on the PBMCs and flow cytometry dot plots were prepared showing the flow scatter area (FSC-A) vs. LD780 tomeasure the live cells, CD8 vs. CD4, GFP vs CD3, GFP vs CD4, and GFP vs CD8 to measure the transduced PBMCs expressing each receptor (FIGs. 35A-35H). These results show a large increase in the number of PBMCs transduced buy the lentiviruses prepared with the multiplexed trimer approach using a 1 : 1 :6 (0.5:0.5:3) ratio of UCHT1-VSV-G-AK47 :NB#28-VSV-G-AK47 : VSV-G-AK47, UCHT1-VSV-G-AK47 : scFv#48-VSV-G-AK47 : VSV-G-AK47, or UCHTl-VSV-G-QQQ :scFv#48- VSV-G-QQQ : VSV-G-QQQ compared to lentiviruses prepared using a mixed trimer approach using a 1 :3 ratio of NB#28-VSV-G- AK47 : VSV-G-AK47, scFv#48-VSV-G-AK47 : VSV-G-AK47, or scFv#48-VSV-G-QQQ : VSV-G-QQQ and comparable levels compared to lentiviruses prepared using a mixed trimer approach using a 1 :3 ratio of UCHT1-VSV-G-AK47 : VSV-G-AK47 or UCHT1- VSV-G- QQQ : VSV-G-QQQ.

[0458] These results suggest that the multiplexing mixed trimer approach can be used to prepare lentiviral particles and other membraned vehicles that are targeted to specific cell populations expressing receptors corresponding to the targeting molecules on the recombinant fusion protein in vivo and could have useful clinical applications.

[0459] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0460] The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0461] Preferred aspects of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred aspects may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law.Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.SEQUENCESIll

Claims

CLAIMS:

1. An enveloped delivery vehicle (EDV), comprising:(1) an envelope membrane;(2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and(3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same.

2. The EDV of claim 1, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

3. The EDV of claim 1 or 2, wherein at least one targeting molecule is a ligand.

4. The EDV of claim 3, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

5. The EDV of claim 1 or 2, wherein at least one targeting molecule is an antibody or portion thereof.

6. The EDV of claim 5, wherein the antibody or portion thereof is a single-chain variable fragment (scFv), a nanobody, or a minibody.

7. The EDV of claim 6, wherein the antibody or portion thereof is a scFv.

8. The EDV of claim 7, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

9. The EDV of claim 8, wherein the VH is N-terminal to the VL.

10. The EDV of claim 8, wherein the VL is N-terminal to the VH.

11. The EDV of any one of claims 8-10, wherein the VH and VL are separated by a flexible linker.

12. The EDV of claim 11, wherein the flexible linker comprises SEQ ID NO: 17.

13. The EDV of claim 6, wherein the antibody or portion thereof is a nanobody.

14. The EDV of claim 13, wherein the nanobody comprises SEQ ID NO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

15. The EDV of claim 6, wherein the antibody or portion thereof is a minibody.

16. The EDV of claim 15, wherein the minibody comprises SEQ ID NO: 104.

17. The EDV of any one of claims 1-16, wherein at least one FMG is N-terminal to at least one targeting molecule in at least one VMG.

18. The EDV of any one of claims 1-17, wherein at least one targeting molecule is N-terminal to at least one FMG in at least one VMG.

19. The EDV of any one of claims 1-18, wherein at least one VMG comprises a linker between at least one FMG and at least one targeting molecule.

20. The EDV of claim 19, wherein the linker is flexible.

21. The EDV of claim 20, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

22. The EDV of claim 19, wherein the linker is rigid.

23. The EDV of claim 22, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ IDNO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

24. The EDV of any one of claims 1-23, wherein the number of VMG(s) of (2) in the envelope membrane is not the same as the number of VMG(s) of (3) in the envelope membrane.

25. The EDV of any one of claims 1-24, wherein the EDV comprises (4) at least one third recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule.

26. The EDV of any one of claim 25, wherein the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

27. The EDV of claim 26, wherein the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is 1 : 1 :6.

28. The EDV of any one of claims 1-27, wherein at least one FMG is engineered to reduce or eliminate binding to its natural receptor.

29. The EDV of any one of claims 1-28, wherein two or more VMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

30. The EDV of any one of claims 1-29, wherein at least one FMG comprises a rhabdoviral G protein.

31. The EDV of claim 30, wherein the rhabdoviral G protein is of a Flanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein (RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawaraglycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), a Bovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), aNiakha glycoprotein (NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G).

32. The EDV of claim 30, wherein the rhabdoviral G protein is of a Vesiculovirus glycoprotein.

33. The EDV of claim 32, wherein the rhabdoviral G protein is of Vesiculovirus Indiana, Vesiculovirus newjersey, Vesiculovirus carajas, or Vesiculovirus alagoas.

34. The EDV of claim 33, wherein the rhabdoviral G protein is of Vesiculovirus Indiana (SEQ ID NO: 9).

35. The EDV of claim 33, wherein the rhabdoviral G protein is of Vesiculovirus newjersey (SEQ ID NO: 10).

36. The EDV of any one of claims 30-35, wherein the rhabdoviral G protein is engineered to have a mutation to reduce or abolish its natural receptor binding specificity.

37. The EDV of any one of claims 30-36, wherein the rhabdoviral G protein comprises a mutation at one or more positions corresponding to H8, K47, Y209, and K354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

38. The EDV of claim 36 or 37, wherein the mutation is a substitution.

39. The EDV of any one of claims 36-38, wherein the substitution is with a Q.

40. The EDV of any one of claims 36-39, wherein the mutation is a substitution at two or more positions.

41. The EDV of any one of claim 36 or 37, wherein the mutation is a deletion.

42. The EDV of claim 41, wherein the mutation is a single deletion at the position corresponding to K47 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

43. A method of generating an enveloped delivery vehicle (EDV), the method comprising:(a) transfecting or transducing a host cell with at least one expression construct encoding at least two recombinant viral membrane glycoproteins (VMGs); wherein at least one first recombinant VMG comprises a fusion protein comprising(A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and(B) a first targeting molecule; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same;(b) maintaining the host cell within suitable conditions for at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(1) an envelope membrane; and(2) at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) that are incorporated into the envelope membrane;(I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a first targeting molecule;(II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; and wherein the first targeting molecule and the second targeting molecule are not the same.

44. The method of claim 43, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKitreceptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

45. The method of claim 43 or 44, wherein at least one targeting molecule is a ligand.

46. The method of claim 45, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

47. The method of claim 43 or 44, wherein at least one targeting molecule is an antibody or portion thereof.

48. The method of claim 47, wherein the antibody or portion thereof is a singlechain variable fragment (scFv), a nanobody, or a minibody.

49. The method of claim 48, wherein the antibody or portion thereof is a scFv.

50. The method of claim 49, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

51. The method of claim 50, wherein the VH is N-terminal to the VL.

52. The method of claim 50, wherein the VL is N-terminal to the VH.

53. The method of any one of claims 50-52, wherein the VH and VL are separated by a flexible linker.

54. The method of claim 53, wherein the flexible linker comprises SEQ ID NO: 17.

55. The method of claim 48, wherein the antibody or portion thereof is a nanobody.

56. The method of claim 55, wherein the nanobody comprises SEQ ID NO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

57. The method of claim 48, wherein the antibody or portion thereof is a minibody.

58. The method of claim 57, wherein the minibody comprises SEQ ID NO: 104.

59. The method of any one of claims 43-58, wherein at least one FMG is N- terminal to at least one targeting molecule in at least one VMG.

60. The method of any one of claims 43-59, wherein at least one targeting molecule is N-terminal to at least one FMG in at least one VMG61. The method of any one of claims 43-60, wherein at least one VMG comprises a linker between at least one FMG and at least one targeting molecule.

62. The method of claim 61, wherein the linker is flexible.

63. The method of claim 62, wherein the linker is: AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

64. The method of claim 61, wherein the linker is rigid.

65. The method of claim 64, wherein the linker is: PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

66. The method of any one of claims 43-65, wherein the number of VMG(s) of (I) in the envelope membrane is not the same as the number of VMG(s) of (II) in the envelope membrane.

67. The method of any one of claims 43-66, comprising(a) transfecting or transducing a host cell with at least one second expression construct encoding at least one third recombinant VMG comprising a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a targeting molecule;(b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one second expression construct of (a) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(3) at least one third recombinant VMG encoded by at least one second expression construct of (a) that is incorporated into the envelope membrane;(III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule.

68. The method of claim 67, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

69. The method of claim 68, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is 1 : 1 :6.

70. A method of generating an enveloped delivery vehicle (EDV), the method comprising:(a) transfecting or transducing a host cell with:(i) at least one first expression construct encoding at least one first recombinant viral membrane glycoprotein (VMG); and(ii) at least one second expression construct encoding at least one second recombinant VMG; wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same;(b) maintaining the host cell within suitable conditions for at least one first recombinant VMG encoded by at least one first expression construct of (i) to be expressed and for at least one second recombinant VMG encoded by at least one second expression construct of (ii) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(1) an envelope membrane;(2) at least one first recombinant VMG encoded by at least one first expression construct of (i) that is incorporated into the envelope membrane; and(3) at least one second recombinant VMG encoded by at least one second expression construct of (ii) that is incorporated into the envelope membrane;(I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a first targeting molecule; and(II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; and wherein the first targeting molecule and the second targeting molecule are not the same.

71. The method of claim 70, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

72. The method of claim 70 or 71, wherein at least one targeting molecule is a ligand.

73. The method of claim 72, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

74. The method of claim 70 or 71, wherein at least one targeting molecule is an antibody or portion thereof.

75. The method of claim 74, wherein the antibody or portion thereof is a singlechain variable fragment (scFv), a nanobody, or a minibody.

76. The method of claim 75, wherein the antibody or portion thereof is a scFv.

77. The method of claim 76, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

78. The method of claim 77, wherein the VH is N-terminal to the VL.

79. The method of claim 77, wherein the VL is N-terminal to the VH.

80. The method of any one of claims 77-79, wherein the VH and VL are separated by a flexible linker.

81. The method of claim 80, wherein the flexible linker comprises SEQ ID NO: 17.

82. The method of claim 75, wherein the antibody or portion thereof is a nanobody.

83. The method of claim 82, wherein the nanobody comprises SEQ ID NO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

84. The method of claim 75, wherein the antibody or portion thereof is a minibody.

85. The method of claim 84, wherein the minibody comprises SEQ ID NO: 104.

86. The method of any one of claims 70-85, wherein at least one FMG is N- terminal to at least one targeting molecule in at least one VMG.

87. The method of any one of claims 70-86, wherein at least one targeting molecule is N-terminal to at least one FMG in at least one VMG88. The method of any one of claims 70-87, wherein at least one VMG comprises a linker between at least one FMG and at least one targeting molecule.

89. The method of claim 88, wherein the linker is flexible.

90. The method of claim 89, wherein the linker is: AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

91. The method of claim 88, wherein the linker is rigid.

92. The method of claim 91, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

93. The method of any one of claims 70-92, wherein the number of VMG(s) of (I) in the envelope membrane is not the same as the number of VMG(s) of (II) in the envelope membrane.

94. The method of any one of claims 70-93, comprising(a) transfecting or transducing a host cell with:(iii) at least one third expression construct encoding at least one third recombinant VMG; wherein at least one third recombinant VMG comprises a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a targeting molecule;(b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one third expression construct of (iii) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(4) at least one third recombinant VMG encoded by at least one third expression construct of (iii) that is incorporated into the envelope membrane;(III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a targeting molecule.

95. The method of claim 94, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

96. The method of claim 95, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is 1 : 1 :6.

97. The method of any one of claims 70-96, wherein the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

98. The method of claim 97, wherein the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is 1 : 1 :6.

99. The method of any one of claims 43-98, wherein at least one FMG is engineered to reduce or eliminate binding to its natural receptor.

100. The method of any one of claims 43-99, wherein two or more VMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

101. The method of any one of claims 43-100, wherein at least one FMG comprises a rhabdoviral G protein.

102. The method of claim 101, wherein the rhabdoviral G protein is of a Flanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein (RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawara glycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), a Bovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), aNiakha glycoprotein (NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G).

103. The method of claim 101, wherein the rhabdoviral G protein is of a Vesiculovirus glycoprotein.

104. The method of claim 101, wherein the rhabdoviral G protein is of Vesiculovirus Indiana, Vesiculovirus new jersey, Vesiculovirus carajas, or Vesiculovirus alagoas.

105. The method of claim 104, wherein the rhabdoviral G protein is of Vesiculovirus Indiana (SEQ ID NO: 9).

106. The method of claim 104, wherein the rhabdoviral G protein is of Vesiculovirus new jersey (SEQ ID NO: 10).

107. The method of any one of claims 101-106, wherein the rhabdoviral G protein is engineered to have a mutation to reduce or abolish its natural receptor binding specificity.

108. The method of any one of claims 101-107, wherein the rhabdoviral G protein comprises a mutation at one or more positions corresponding to H8, K47, Y209, and K354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

109. The method of claim 107 or 108, wherein the mutation is a substitution.

110. The method of any one of claims 107-109, wherein the substitution is with a Q111. The method of any one of claims 110, wherein the mutation is a substitution at two or more positions.

112. The method of any one of claim 107 or 108, wherein the mutation is a deletion.

113. The method of claim 112, wherein the mutation is a single deletion at the position corresponding to K47 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

114. The method of any one of claims 43-113, wherein transfecting or transducing a host cell comprises transfecting or transducing with at least one packaging plasmid.

115. The method of any one of claims 43-114, wherein expression of at least one VMG is under the control of a drug-inducible promoter.

116. The method of claim 115, wherein expression of at least two VMGs that are not the same are each under the control of separate drug-inducible promoters that are not the same.

117. A method of improving the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a first targeting molecule; the method comprising designing or preparing the EDV to comprise at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a second targeting molecule; wherein the first targeting molecule and the second targeting molecule are not the same..

118. The method of claim 117, wherein the EDV is generated according to any one of claims 43-116.

119. The method of claim 117 or 118, wherein the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant viral membrane glycoprotein (VMG) and not comprising the at least one second recombinant VMG.

120. The method of any one of claims 117-119, wherein the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one second recombinant viral membrane glycoprotein (VMG) and not comprising the at least one first recombinant VMG.

121. The method of any one of claims 117-120, wherein the cell infection efficiency is increased by more than a 1 fold change.

122. The method of any one of claims 117-121, wherein the cell infection efficiency is increased by more than a 5 fold change.

123. The method of any one of claims 117-122, wherein the cell infection efficiency is increased by more than a 10 fold change.

124. The method of any one of claims 117-123, wherein the cell infection efficiency is increased by more than a 20 fold change.

125. The method of any one of claims 117-124, wherein the first targeting molecule targets a CD3 receptor.

126. The method of claim 125, wherein the first targeting molecule comprises a single-chain variable fragment (scFv) UCHT1 comprising a variable heavy chain (VH) comprising the amino acid sequence of SEQ ID NO: 27 and a variable light chain (VL) comprising of the amino acid sequence of SEQ ID NO: 26127. The method of any one of claims 117-126, wherein the second targeting molecule targets a CD4 receptor.

128. The method of claim 127, wherein the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 100.

129. The method of claim 127, wherein the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 72 and a VL comprising of the amino acid sequence of SEQ ID NO: 73.

130. The method of any one of claims 117-126, wherein the second targeting molecule targets a CD8 receptor.

131. The method of claim 130, wherein the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 102.

132. The method of claim 130, wherein the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 88 and a VL comprising of the amino acid sequence of SEQ ID NO: 89.

133. An enveloped delivery vehicle (EDV) comprising:(1) an envelope membrane;(2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; and(3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; wherein the other recombinant fusion protein of (2) is not the same as the other recombinant fusion protein of (3); and wherein the EDV is produced using retrovirus infection.

134. The EDV of claim 133, wherein the retrovirus is a lentivirus.

135. The EDV of claim 133 or 134, wherein the EDV comprises (4) at least one third recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

136. The EDV of any one of claims 133-135, wherein at least one polypeptide tag is Spy Tag (SEQ ID NO: 187), SpyTag002 (SEQ ID NO: 189), SpyTag003 (SEQ ID NO: 191), Isopeptag (SEQ ID NO: 194), or SnoopTag (SEQ ID NO: 196).

137. The EDV of any one of claims 133-136, wherein at least one polypeptide catcher is SpyCatcher (SEQ ID NO: 188), SpyCatcher002 (SEQ ID NO: 190), SpyCatcher003 (SEQ ID NO: 192), KTag (SEQ ID NO: 193), pilin-C (SEQ ID NO: 195), or SnoopCatcher (SEQ ID NO: 197).

138. The EDV of any one of claims 133-137, wherein the other recombinant fusion protein of (2) comprises a first targeting molecule and the other recombinant fusion protein of (3) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

139. The EDV of claim 138, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

140. The EDV of claim 138 or 139, wherein at least one targeting molecule is a ligand.

141. The EDV of claim 139, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

142. The EDV of claim 138 or 139, wherein at least one targeting molecule is an antibody or portion thereof.

143. The EDV of claim 142, wherein the antibody or portion thereof is a singlechain variable fragment (scFv), a nanobody, or a minibody.

144. The EDV of claim 143, wherein the antibody or portion thereof is a scFv.

145. The EDV of claim 144, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75,a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

146. The EDV of claim 145, wherein the VH is N-terminal to the VL.

147. The EDV of claim 145, wherein the VL is N-terminal to the VH.

148. The EDV of any one of claims 145-147, wherein the VH and VL are separated by a flexible linker.

149. The EDV of claim 148, wherein the flexible linker comprises SEQ ID NO: 17.

150. The EDV of claim 143, wherein the antibody or portion thereof is a nanobody.

151. The EDV of claim 150, wherein the nanobody comprises SEQ ID NO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

152. The EDV of claim 143, wherein the antibody or portion thereof is a minibody.

153. The EDV of claim 152, wherein the minibody comprises SEQ ID NO: 104.

154. The EDV of any one of claims 138-153, wherein at least one polypeptide catcher is N-terminal to at least one targeting molecule in at least one other recombinant fusion protein.

155. The EDV of any one of claims 138-154, wherein at least one targeting molecule is N-terminal to at least one polypeptide catcher in at least one other recombinant fusion protein156. The EDV of any one of claims 138-155, wherein at least one other recombinant fusion protein comprises a linker between at least one polypeptide catcher and at least one targeting molecule.

157. The EDV of claim 156, wherein the linker is flexible.

158. The EDV of claim 157, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

159. The EDV of claim 156, wherein the linker is rigid.

160. The EDV of claim 159, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ IDNO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

161. The EDV of any one of claims 133-160, wherein the number of VMG(s) of (2) in the envelope membrane is not the same as the number of VMG(s) of (3) in the envelope membrane.

162. The EDV of any one of claims 135-161, wherein the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

163. The EDV of claim 162, wherein the ratio of VMG(s) of (2) in the envelope membrane to VMG(s) of (3) in the envelope membrane to VMG(s) of (4) in the envelope membrane is 1 : 1 :6.

164. The EDV of any one of claims 133-163, wherein at least one FMG is engineered to reduce or eliminate binding to its natural receptor.

165. The EDV of any one of claims 133-164, wherein two or more VMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

166. The EDV of any one of claims 133-165, wherein at least one FMG comprises a rhabdoviral G protein.

167. The EDV of claim 166, wherein the rhabdoviral G protein is of a Flanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein (RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawara glycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), a Bovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), a Niakha glycoprotein(NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G).

168. The EDV of claim 166, wherein the rhabdoviral G protein is of a Vesiculovirus glycoprotein.

169. The EDV of claim 168, wherein the rhabdoviral G protein is of Vesiculovirus Indiana, Vesiculovirus newjersey, Vesiculovirus carajas, or Vesiculovirus alagoas.

170. The EDV of claim 169, wherein the rhabdoviral G protein is of Vesiculovirus Indiana (SEQ ID NO: 9).

171. The EDV of claim 169, wherein the rhabdoviral G protein is of Vesiculovirus newjersey (SEQ ID NO: 10).

172. The EDV of any one of claims 166-171, wherein the rhabdoviral G protein is engineered to have a mutation to reduce or abolish its natural receptor binding specificity.

173. The EDV of any one of claims 166-172, wherein the rhabdoviral G protein comprises a mutation at one or more positions corresponding to H8, K47, Y209, and K354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

174. The EDV of claim 172 or 173, wherein the mutation is a substitution.

175. The EDV of any one of claims 172-174, wherein the substitution is with a Q.

176. The EDV of any one of claims 172-175, wherein the mutation is a substitution at two or more positions.

177. The EDV of any one of claim 172 or 173, wherein the mutation is a deletion.

178. The EDV of claim 177, wherein the mutation is a single deletion at the position corresponding to K47 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

179. A method of generating an enveloped delivery vehicle (EDV), the method comprising:(a) transfecting or transducing a host cell with at least one expression construct encoding at least two recombinant viral membrane glycoproteins (VMGs); wherein at least one first recombinant VMG comprises a fusion protein comprising(A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and(B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag;(b) maintaining the host cell within suitable conditions for at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(1) an envelope membrane; and(2) at least one first recombinant VMG and at least one second recombinant VMG encoded by at least one expression construct of (a) that are incorporated into the envelope membrane;(I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag;(II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising asubstantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and(d) covalently bonding to at least one first recombinant VMG of (c) a polypeptide catcher within another recombinant fusion protein and covalently bonding to at least one second VMG of (c) a polypeptide catcher within another recombinant fusion protein, wherein the other recombinant fusion protein covalently bound to at least one first recombinant VMG of (c) is not the same as the other recombinant fusion protein covalently bound to at least one second recombinant VMG of (c); and wherein the EDV is produced using retrovirus infection.

180. The method of claim 179, wherein the retrovirus is a lentivirus.

181. The method of claim 179 or 180, comprising(a) transfecting or transducing a host cell with at least one second expression construct encoding at least one third recombinant VMG comprising a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein;(b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one second expression construct of (a) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(3) at least one third recombinant VMG encoded by at least one second expression construct of (a) that is incorporated into the envelope membrane;(III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising asubstantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

182. The method of any one of claims 179-181, wherein at least one polypeptide tag is SpyTag (SEQ ID NO: 187), SpyTag002 (SEQ ID NO: 189), SpyTag003 (SEQ ID NO: 191), Isopeptag (SEQ ID NO: 194), or SnoopTag (SEQ ID NO: 196).

183. The method of any one of claims 179-182, wherein at least one polypeptide catcher is SpyCatcher (SEQ ID NO: 188), SpyCatcher002 (SEQ ID NO: 190), SpyCatcher003 (SEQ ID NO: 192), KTag (SEQ ID NO: 193), pilin-C (SEQ ID NO: 195), or SnoopCatcher (SEQ ID NO: 197).

184. The method of any one of claims 179-183, wherein the other recombinant fusion protein of (I) comprises a first targeting molecule and the other recombinant fusion protein of (II) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

185. The method of claim 184, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

186. The method of claim 184 or 185, wherein at least one targeting molecule is a ligand.

187. The method of claim 186, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

188. The method of claim 184 or 185, wherein at least one targeting molecule is an antibody or portion thereof.

189. The method of claim 188, wherein the antibody or portion thereof is a singlechain variable fragment (scFv), a nanobody, or a minibody.

190. The method of claim 189, wherein the antibody or portion thereof is a scFv.

191. The method of claim 190, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85, a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

192. The method of claim 191, wherein the VH is N-terminal to the VL.

193. The method of claim 191, wherein the VL is N-terminal to the VH.

194. The method of any one of claims 191-193, wherein the VH and VL are separated by a flexible linker.

195. The method of claim 194, wherein the flexible linker comprises SEQ ID NO: 17.

196. The method of claim 189, wherein the antibody or portion thereof is a nanobody.

197. The method of claim 196, wherein the nanobody comprises SEQ ID NO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

198. The method of claim 189, wherein the antibody or portion thereof is a minibody.

199. The method of claim 198, wherein the minibody comprises SEQ ID NO: 104.

200. The method of any one of claims 179-199, wherein at least one polypeptide catcher is N-terminal to at least one targeting molecule in at least one other recombinant fusion protein.

201. The method of any one of claims 179-200, wherein at least one targeting molecule is N-terminal to at least one polypeptide catcher in at least one other recombinant fusion protein202. The method of any one of claims 179-201, wherein at least one other recombinant fusion protein comprises a linker between at least one polypeptide catcher and at least one targeting molecule.

203. The method of claim 202, wherein the linker is flexible.

204. The method of claim 203, wherein the linker is: AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

205. The method of claim 202, wherein the linker is rigid.

206. The method of claim 205, wherein the linker is: PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ ID NO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

207. The method of any one of claims 179-206, wherein the number of VMG(s) of (I) in the envelope membrane is not the same as the number of VMG(s) of (II) in the envelope membrane.

208. The method of any one of claims 181-207, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

209. The method of claim 208, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is 1 : 1 :6.

210. A method of generating an enveloped delivery vehicle (EDV), the method comprising:(a) transfecting or transducing a host cell with:(i) at least one first expression construct encoding at least one first recombinant viral membrane glycoprotein (VMG); and(ii) at least one second expression construct encoding at least one second recombinant VMG; wherein at least one first recombinant VMG comprises a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and wherein at least one second recombinant VMG comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide(polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag;(b) maintaining the host cell within suitable conditions for at least one first recombinant VMG encoded by at least one first expression construct of (i) to be expressed and for at least one second recombinant VMG encoded by at least one second expression construct of (ii) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(1) an envelope membrane;(2) at least one first recombinant VMG encoded by at least one first expression construct of (i) that is incorporated into the envelope membrane; and(3) at least one second recombinant VMG encoded by at least one second expression construct of (ii) that is incorporated into the envelope membrane;(I) wherein at least one first recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag;(II) wherein at least one second recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag; and(d) covalently bonding to at least one first recombinant VMG of (c) a polypeptide catcher within another recombinant fusion protein and covalently bonding to at least one second VMG of (c) a polypeptide catcher within another recombinant fusion protein,wherein the other recombinant fusion protein covalently bound to at least one first recombinant VMG of (c) is not the same as the other recombinant fusion protein covalently bound to at least one second recombinant VMG of (c); and wherein the EDV is produced using retrovirus infection.

211. The method of claim 210, wherein the retrovirus is a lentivirus.

212. The method of claim 210 or 211, comprising(a) transfecting or transducing a host cell with:(iii) at least one third expression construct encoding at least one third recombinant VMG; wherein at least one third recombinant VMG comprises a fusion protein comprising a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein;(b) maintaining the host cell within suitable conditions for at least one third recombinant VMG encoded by at least one third expression construct of (iii) to be expressed; and(c) collecting an EDV from the host cell, the EDV comprising:(4) at least one third recombinant VMG encoded by at least one third expression construct of (iii) that is incorporated into the envelope membrane;(III) wherein at least one third recombinant VMG incorporated into the envelope membrane comprises a fusion protein comprising a FMG comprising a substantially intact FMG that does not comprise a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein.

213. The method of any one of claims 210-212, wherein at least one polypeptide tag is SpyTag (SEQ ID NO: 187), SpyTag002 (SEQ ID NO: 189), SpyTag003 (SEQ ID NO: 191), Isopeptag (SEQ ID NO: 194), or SnoopTag (SEQ ID NO: 196).

214. The method of any one of claims 210-213, wherein at least one polypeptide catcher is SpyCatcher (SEQ ID NO: 188), SpyCatcher002 (SEQ ID NO: 190), SpyCatcher003 (SEQ ID NO: 192), KTag (SEQ ID NO: 193), pilin-C (SEQ ID NO: 195), or SnoopCatcher (SEQ ID NO: 197).

215. The method of any one of claims 210-214, wherein the other recombinant fusion protein of (I) comprises a first targeting molecule and the other recombinant fusion protein of (II) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

216. The method of claim 215, wherein the first targeting molecule and the second targeting molecule each independently bind to a target selected from EGFR, cKit receptor / CD117, TPOR, CD3, CD4, CD8, c-Met receptor tyrosine kinase, and type 1 insulinlike growth factor receptor.

217. The method of claim 215 or 216, wherein at least one targeting molecule is a ligand.

218. The method of claim 217, wherein the ligand comprises epidermal growth factor (EGF), a mutant EGF (EFGml23), stem cell factor (SCF), thrombopoietin (TPO), human hepatocyte growth factor (HGF), or type 1 insulin-like growth factor (IGF1).

219. The method of claim 215 or 216, wherein at least one targeting molecule is an antibody or portion thereof.

220. The method of claim 219, wherein the antibody or portion thereof is a singlechain variable fragment (scFv), a nanobody, or a minibody.

221. The method of claim 220, wherein the antibody or portion thereof is a scFv.

222. The method of claim 221, wherein the scFv comprises a variable heavy chain (VH) of SEQ ID NO: 27 and a variable light chain (VL) of SEQ ID NO: 26, a VH of SEQ ID NO: 72 and a VL of SEQ ID NO: 73, a VH of SEQ ID NO: 74 and a VL of SEQ ID NO: 75, a VH of SEQ ID NO: 76 and a VL of SEQ ID NO: 77, a VH of SEQ ID NO: 78 and a VL of SEQ ID NO: 79, a VH of SEQ ID NO: 80 and a VL of SEQ ID NO: 81, a VH of SEQ ID NO: 82 and a VL of SEQ ID NO: 83, a VH of SEQ ID NO: 84 and a VL of SEQ ID NO: 85,a VH of SEQ ID NO: 86 and a VL of SEQ ID NO: 87, a VH of SEQ ID NO: 88 and a VL of SEQ ID NO: 89, a VH of SEQ ID NO: 90 and a VL of SEQ ID NO: 91, a VH of SEQ ID NO: 92 and a VL of SEQ ID NO: 93, a VH of SEQ ID NO: 94 and a VL of SEQ ID NO: 95, or a VH of SEQ ID NO: 96 and a VL of SEQ ID NO: 97.

223. The method of claim 222, wherein the VH is N-terminal to the VL.

224. The method of claim 222, wherein the VL is N-terminal to the VH.

225. The method of any one of claims 222-224, wherein the VH and VL are separated by a flexible linker.

226. The method of claim 225, wherein the flexible linker comprises SEQ ID NO: 17.

227. The method of claim 220, wherein the antibody or portion thereof is a nanobody.

228. The method of claim 227, wherein the nanobody comprises SEQ ID NO: 100, SEQ ID NO: 101, SEQ ID NO: 102, or SEQ ID NO: 103.

229. The method of claim 220, wherein the antibody or portion thereof is a minibody.

230. The method of claim 229, wherein the minibody comprises SEQ ID NO: 104.

231. The method of any one of claims 215-230, wherein at least one polypeptide catcher is N-terminal to at least one targeting molecule in at least one other recombinant fusion protein.

232. The method of any one of claims 215-231, wherein at least one targeting molecule is N-terminal to at least one polypeptide catcher in at least one other recombinant fusion protein233. The method of any one of claims 215-232, wherein at least one other recombinant fusion protein comprises a linker between at least one polypeptide catcher and at least one targeting molecule.

234. The method of claim 233, wherein the linker is flexible.

235. The method of claim 234, wherein the linker is:AAASGGSGGGGSGGGGSGP (SEQ ID NO: 49),AAASGGSGGGGSGGGGS (SEQ ID NO: 50),GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 51),GGGGSGGGGSGGGGS (SEQ ID NO: 17),GGGGSGGGGS (SEQ ID NO: 52),GGGGS (SEQ ID NO: 53),GGGGGGGG (SEQ ID NO: 54),GGGGGG (SEQ ID NO: 55),GSAGSAAGSGEF (SEQ ID NO: 56), orVPGVGVPGVG (SEQ ID NO: 57).

236. The method of claim 234, wherein the linker is rigid.

237. The method of claim 236, wherein the linker is:PAPAP (SEQ ID NO: 58),EAAAKEAAAKEAAAK (SEQ ID NO: 59),EAAAKEAAAK (SEQ ID NO: 60),EAAAK (SEQ ID NO: 61), AEAAAKEAAAKEAAAKEAAAKALEAEAAAKEAAAKEAAAKEAAAKA (SEQ IDNO: 62),AEAAAKEAAAKA (SEQ ID NO: 63),ESKYGPPCPPCP (SEQ ID NO: 64),CPPCPAPELLGGPSVF (SEQ ID NO: 65), or alanine-proline (AP) repeated for a total of 10 to 34 amino acids (SEQ ID NO: 66).

238. The method of any one of claims 210-237, wherein the number of VMG(s) of (I) in the envelope membrane is not the same as the number of VMG(s) of (II) in the envelope membrane.

239. The method of any one of claims 212-238, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

240. The method of claim 239, wherein the ratio of VMG(s) of (I) in the envelope membrane to VMG(s) of (II) in the envelope membrane to VMG(s) of (III) in the envelope membrane is 1 : 1 :6.

241. The method of any one of claims 210-240, wherein the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is from 1 : 1 : 1 to 1 : 1 :9 or from 1 : 1 : 1 to 1 :9: 1 or from 1 : 1 : 1 to 9: 1 : 1.

242. The method of claim 241, wherein the ratio of the first expression construct of (i) to the second expression construct of (ii) to the third expression construct of (iii) is 1 : 1 :6.

243. The method of any one of claims 179-242, wherein at least one FMG is engineered to reduce or eliminate binding to its natural receptor.

244. The method of any one of claims 179-243, wherein two or more VMGs that are not the same hetero-oligomerize to form at least one protomer-complex.

245. The method of any one of claims 179-244, wherein at least one FMG comprises a rhabdoviral G protein.

246. The method of claim 245, wherein the rhabdoviral G protein is of a Flanders virus glycoprotein (FLAV-G) (SEQ ID NO: 1), a Chandipura virus glycoprotein (CHPV-G) (SEQ ID NO: 2), a Perinet virus glycoprotein (PERV-G) (SEQ ID NO: 3), a Piry virus glycoprotein (PIRYV-G) (SEQ ID NO: 4), a Fukuoka virus glycoprotein (FUKV-G) (SEQ ID NO: 5), a Joinjakaka virus glycoprotein (JOIV-G) (SEQ ID NO: 6), a Kumasi virus glycoprotein (KRV-G) (SEQ ID NO: 7), a Keuraliba virus glycoprotein (KEUV-G) (SEQ ID NO: 8), an Isfahan glycoprotein (ISFV-G), a Jurona glycoprotein (JURV-G), a Mediterranean Bat glycoprotein (MBV-G), a Malpais Spring glycoprotein (MSPV-G), a Radi glycoprotein(RADV-G), a Rhinolophus affinis-G, a Yug Bugdanavoc glycoprotein (YBV-G), a Yinshui Bat glycoprotein (YSBV-G), a Kimberley glycoprotein (KIMV-G), a Kanyawara glycoprotein (KYAV-G), a La Joya glycoprotein (LJV-G), a Mosquiero glycoprotein (MQOV-G), a Parry Creek glycoprotein (PCV-G), a Bas Congo glycoprotein (BASV-G), a Bovine Ephemeral fever glycoprotein (BEFV-G), a Curionopolis glycoprotein (CURV-G), a Drosophila melanogaster sigmavirus glycoprotein (DMelSV-G), aNiakha glycoprotein (NIAV-G), a Puerto almandras glycoprotein (PTAMV-G), or a Tupaia rhabdovirus (TUPTV- G).

247. The method of claim 245, wherein the rhabdoviral G protein is of a Vesiculovirus glycoprotein.

248. The method of claim 247, wherein the rhabdoviral G protein is of Vesiculovirus Indiana, Vesiculovirus new jersey, Vesiculovirus carajas, or Vesiculovirus alagoas.

249. The method of claim 248, wherein the rhabdoviral G protein is of Vesiculovirus indiana (SEQ ID NO: 9).

250. The method of claim 249, wherein the rhabdoviral G protein is of Vesiculovirus new jersey (SEQ ID NO: 10).

251. The method of any one of claims 245-250, wherein the rhabdoviral G protein is engineered to have a mutation to reduce or abolish its natural receptor binding specificity.

252. The method of any one of claims 245-251, wherein the rhabdoviral G protein comprises a mutation at one or more positions corresponding to H8, K47, Y209, and K354 on the Vesiculovirus indiana glycoprotein (SEQ ID NO: 9).

253. The method of claim 251 or 252, wherein the mutation is a substitution.

254. The method of any one of claims 251-253, wherein the substitution is with a Q255. The method of any one of claims 252-254, wherein the mutation is a substitution at two or more positions.

256. The method of claim 251 or 252, wherein the mutation is a deletion.

257. The method of claim 256, wherein the mutation is a single deletion at the position corresponding to K47 on the Vesiculovirus Indiana glycoprotein (SEQ ID NO: 9).

258. The method of any one of claims 179-257, wherein transfecting or transducing a host cell comprises transfecting or transducing with at least one packaging plasmid.

259. The method of any one of claims 179-258, wherein expression of at least one VMG is under the control of a drug-inducible promoter.

260. The method of claim 259, wherein expression of at least two VMGs that are not the same are each under the control of separate drug-inducible promoters that are not the same.

261. A method of improving the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having (1) an envelope membrane and (2) at least one first recombinant viral membrane glycoprotein (VMG) incorporated into the envelope membrane comprising a fusion protein comprising (A) a fusogenic membrane glycoprotein (FMG) comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher; and the method comprising designing or preparing the EDV to comprise (3) at least one second recombinant VMG incorporated into the envelope membrane comprising a fusion protein comprising (A) a FMG comprising a substantially intact FMG and (B) a polypeptide (polypeptide tag) that is capable of forming a covalent bond with an amino acid residue in another recombinant fusion protein, wherein the other recombinant fusion protein comprises a polypeptide (polypeptide catcher) that is capable of forming a covalent bond with an amino acid residue in the polypeptide tag, wherein the polypeptide tag is covalently bonded to the polypeptide catcher;wherein the other recombinant fusion protein of (2) is not the same as the other recombinant fusion protein of (3).

262. The method of claim 261, wherein the EDV is generated according to any one of claims 179-263.

263. The method of claim 261 or 262, wherein the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant viral membrane glycoprotein (VMG) and not comprising the at least one second recombinant VMG.

264. The method of any one of claims 261-263, wherein the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one first recombinant VMG and the at least one second recombinant VMG is increased relative to the cell infection efficiency of an enveloped delivery vehicle (EDV) designed to have or having an envelope membrane and the at least one second recombinant viral membrane glycoprotein (VMG) and not comprising the at least one first recombinant VMG.

265. The method of any one of claims 261-264, wherein the cell infection efficiency is increased by more than a 1 fold change.

266. The method of any one of claims 261-265, wherein the cell infection efficiency is increased by more than a 5 fold change.

267. The method of any one of claims 261-266, wherein the cell infection efficiency is increased by more than a 10 fold change.

268. The method of any one of claims 261-267, wherein the cell infection efficiency is increased by more than a 20 fold change.

269. The method of any one of claims 179-182, wherein the other recombinant fusion protein of (2) comprises a first targeting molecule and the other recombinant fusionprotein of (3) comprises a second targeting molecule and wherein the first targeting molecule and the second targeting molecule are not the same.

270. The method of claim 269, wherein the first targeting molecule targets a CD3 receptor.

271. The method of claim 270, wherein the first targeting molecule comprises a single-chain variable fragment (scFv) UCHT1 comprising a variable heavy chain (VH) comprising the amino acid sequence of SEQ ID NO: 27 and a variable light chain (VL) comprising of the amino acid sequence of SEQ ID NO: 26272. The method of any one of claims 269-271, wherein the second targeting molecule targets a CD4 receptor.

273. The method of claim 272, wherein the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 100.

274. The method of claim 272, wherein the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 72 and a VL comprising of the amino acid sequence of SEQ ID NO: 73.

275. The method of any one of claims 269-271, wherein the second targeting molecule targets a CD8 receptor.

276. The method of claim 275, wherein the second targeting molecule comprises a nanobody comprising the amino acid sequence of SEQ ID NO: 102.

277. The method of claim 275, wherein the second targeting molecule comprises a scFv comprising a VH comprising the amino acid sequence of SEQ ID NO: 88 and a VL comprising of the amino acid sequence of SEQ ID NO: 89.

Images