Malaria immune response refocusing

Abstract

Provided are compounds and methods of making and utilizing the same. Disclosed compounds and methods are effective at refocusing an immunodominant antibody response to a less dominant antibody response, the latter which can be more protective and superior against infections.

Description

MALARIA IMMUNE RESPONSE REFOCUSINGCROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Serial Number 63 / 550,938, filed on February 7, 2024, and titled “MALARIA IMMUNE RESPONSE REFOCUSING,” which is incorporated by reference herein.REFERENCE TO AN ELECTRONIC SEQUENCE LISTING

[0002] The contents of the electronic sequence listing (AABT_003_01WO_SeqList_ST26.xml; Size: 6,292 bytes and Date of Creation: February 5, 2025) are herein incorporated by reference in its entirety.FIELD

[0003] The present disclosure relates to compositions and methods of modifying an immune response. More specifically, the disclosure pertains to compounds that modify the immune response to malaria parasites, particularly the antibody response to the circumsporozoite protein.BACKGROUND

[0004] Malaria remains a major global health challenge. While incidence has declined over the past 15 years, progress is hindered by drug-resistant parasite strains and insecticide-resistant mosquitoes. In response, the WHO has prioritized malaria vaccine development. RTS,S / AS01e (RTS,S), the most advanced candidate, is a Plasmodium falciparum CSP -based vaccine containing 19 NANP repeats. Despite clinical testing, RTS,S has limited efficacy and shortlived protection, requiring booster doses. Further, anti-NANP antibodies binding the vaccine may reduce its immunogenicity, raising concerns about long-term effectiveness. Current prevention strategies also face challenges, including resistance to antimalarial drugs and insecticides, highlighting the need for improved treatment modalities.SUMMARY

[0005] The present disclosure relates to a method to refocus the immune response to malaria parasites. The refocusing pertains to suppression of an immunodominant antibody response in favor of less dominant antibody responses, the latter which may be more protective against infection and thus desirable for the prevention of disease. In the present case, suppression of antibody responses to NANP major repeat sequence from the circumsporozoite protein (CSP) lead to the production of antibody responses to minor repeat sequences containing the NVDP sequence. In the absence of anti-NANP repeat antibodies, the more protective anti-NVDP repeat antibodies can be generated and bind the CSP without interference from anti-NANP antibodies.

[0006] Provided is a compound, having the formula:or a pharmacologically acceptable salt thereof; the scaffold being covalently bound to the epitope; wherein the epitope comprises one or more NANPx peptide groups, wherein x is 2 to 20; and wherein o is 2-70. In aspects, the scaffold comprises one or more of polymer, dendrimer, peptide-based dendrimer, nanoparticle, dextran, cyclodextrin, a-cyclodextrin, P- cyclodextrin, y-cyclodextrin, dexamine, polyacrylamide, polyvinylpyrolidone, non-ionic synthetic sucrose polymer, carboxymethyl-cellulose, polyvinylalcohol, poly(D-lysine), poly(D-glutamic acid), D-lysine, poly(L-lysine), poly(L-glutamic acid), L-lysine, human serum albumin, gammaglobulin, liposome, or combination thereof. In aspects, the scaffold comprises dextran. In aspects, the scaffold comprises a peptide-based dendrimer derived from a D-lysyl-P-alanine (amide) core peptide, subsequent glycine spacer residue addition, and two successive rounds of D-lysine, then glycine addition. In aspects, the scaffold is valence- restricted. In aspects, the scaffold is covalently bound to the epitope or a pharmacologically acceptable salt thereof. In aspects, the compound further comprises one or more linker group between the epitope and the scaffold. In aspects, the scaffold is non-immunogenic. In aspects, the scaffold is soluble in physiologically acceptable aqueous solution, buffer, or both. In aspects, the compound is soluble in physiologically acceptable aqueous solution, buffer, orboth. In aspects, o is 10-60. In aspects, o is 12-50. In aspects, o is 12-30. In aspects, o is 20. In aspects, the compound is prepared by conjugating an Ac-(NANP)4-Cys-amine to an aminodextran via N-hydroxysuccinimide chemistry using a 24-PEG linker via terminal cysteine on the peptide.

[0007] Provided are also methods for making compounds of the disclosure, comprising contacting scaffolds with one or more epitopes, and covalently bonding a scaffold to one or more epitopes, to form a compound. In aspects, a compound has the formula:or a pharmacologically acceptable salt thereof; wherein A is a linking group; wherein B comprises an NANPx peptide, in which x is 2 to 20; wherein z is 0 or 1; wherein y is 0-20; wherein n is 0 to 50; and wherein o is 2-70.

[0008] Provided are also methods for making a compound, comprising contacting a scaffold having the below formula comprising one or more covalent-binding reactive group A’ thereon with one or more of an epitope having the following formula comprising a covalent-binding reactive group A” thereon, and covalently bonding, to form the below compound;

[0009] or a pharmacologically acceptable salt thereof; wherein m is > o.

[0010] In aspects a compound has the formula:

[0011] wherein m = 0-100; wherein n is 0 to 50; wherein o is 2-70. In aspects, the dextran has a molecular weight (MW) of about 10-80 kDa. In aspects, the dextran has a molecular weight (MW) of about 40 kDa. In aspects, the dextran has a molecular weight (MW) of about 40 kDa, in which >95% is within the range of 35-45 kDa. In aspects, m = 0. In aspects, o = 20. In aspects, n = 4 to 300. In aspects, n = 4 to 50. In aspects, n = 4 to 30. In aspects, n = 4 to 26. In aspects, n = 23.

[0012] Provided are also composition, comprising compounds of the disclosure and a pharmaceutically acceptable carrier. In aspects, compositions can further comprise a Malaria CSP vaccine.

[0013] Provided are methods of treating, suppressing or preventing an anti-NANPx antibody response in a subject in need thereof or at risk thereof, comprising administering to said subject a compound of the disclosure. In aspects, the antibody response is an IgG or IgM antibody response.

[0014] Provided are methods of enhancing the effectiveness of a malaria vaccine in a subject, comprising administering a compound or composition of the disclosure to a subject in need thereof.

[0015] Provided are also methods of enhancing an anti-malarial immune response in a subject infected with or at risk of infection to malaria, comprising administering a compound or composition of the disclosure to the subject.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 shows the general structure of the circumsporozoite protein (CSP).

[0017] FIG. 2 shows an exemplary treatment and bleed collection schedule for animal studies.

[0018] FIG. 3 shows antibody responses to CSP peptides with and without treatment using compounds of the disclosure.

[0019] FIG. 4 shows antibody responses to CSP peptides following vaccine immunization four months after previous immunization on Day 28.

[0020] FIG. 5 shows synthetic peptide sequences used for fine mapping of antibody responses.

[0021] FIG. 6 shows fine mapping of antibody responses to immunization and treatment with compounds of the disclosure.DETAILED DESCRIPTION

[0022] The immune response is important for protecting the body against diseases and toxic agents. Examples of such protective immune responses include the generation of antibodies that protect against agents such as toxins (e.g., tetanus toxin) and pathogens (e.g., polio virus). In some instances, however, it is desirable to alter or bias an antibody response away from one molecular target (e.g., an immunodominant epitope, antibodies against which may be less protective or harmful) in favor of another target (e.g., a less dominant epitope, antibodies against which may be highly protective). Refocusing of such immune responses may be desirable.

[0023] The malaria parasite life cycle is complex, incorporating several different forms and stages of infection in the mammalian and insect hosts. The sporozoite stage of the parasite is first introduced into the mammalian host via the bite of an infected mosquito, wherein it promptly invades liver cells, replicates, and releases into the blood stream the merozoite form which then begins the blood stage infection cycle. While synchronously cycling from red blood cell to red blood cell, resulting in the characteristic relapsing fevers malaria is known for, other forms known as the gametocytes are formed and taken up by mosquitos during another bite and wherein the insect stages of development complete the parasite life cycle. The focus of the present disclosure is on the parasite stage that initially infects the human host, i.e., the sporozoite. The molecular target is the circumsporozoite protein (CSP), the major coat protein that covers the infecting sporozoite.

[0024] Immune refocusing is desirable in immunization strategies (e.g., vaccines) to bias the immune response away from one epitope in order to better focus the immune response toward other specific epitopes of greater interest. An example is presented for immune responses to the malaria circumsporozoite protein (CSP), where it is desirable to decrease the immunodominant immune responses to the NANP major repeat sequence within the CSP infavor of immune responses to the less dominant but more protective NVDP-containing minor repeats that are found immediately after the highly conserved Region 1 motif of the CSP (Flores-Garcia et al., 2021). Antibody targeting the region containing the NVDP minor repeats, close to the conserved proteolytic cleavage motif (Region 1), may impact the enzymatic processing of the CSP required for liver cell invasion (Flores-Garcia et al., 2021; Coppi et al., 2011), thus providing better inhibition of invasion. Immune evasion by the parasite may thus involve the immunodominant major repeat (NANP)x to maintain focus away from the minor repeat NVDP found after the Region 1 motif as described below.

[0025] The general structure of the CSP is shown at Fig. 1. The recognized components of the CSP comprise a signal peptide sequence (SP), an N-terminal non-repeat domain that contains a phylogenetically conserved sequence found in all CSPs (Region 1, or “Rl”), a repeat domain consisting of a major tetramer repeat (amino acid sequence Asn-Ala-Asn-Pro, or “NANP”, denoted by the white boxes) and a minor tetramer repeat (Asn-Val-Asp-Pro, or “NVDP”, denoted by the grey boxes), and a C-terminal non-repeat domain that contains a region containing many T cell epitopes (R3), a thrombospondin-binding domain (TSR), and a GPI anchor sequence (GPI). The CSP protein forms a dense coat on the sporozoite’s surface structured such that the N-terminal domain masks the TSR as the parasite migrates from the mosquito to the mammalian liver, where a protease cleaves the protein at Region I which then leads to removal of the N-terminus and exposure of the TSR, thus rendering the sporozoite invasive in the mammalian host (Coppi et al., 2011). The length of the repeat domain has been demonstrated to affect the motility and adhesion site dynamics of the sporozoite (Balaban et al., 2021). Minor repeats at the N-terminal portion of the repeat domain are typically found across the CSP of all malaria parasites, pointing to the importance of differentiating this portion of the protein from the rest of the repeat domain.

[0026] Malaria vaccine candidates have incorporated parts of the CSP of the parasite, P. falciparum, and virtually all contain repeats found within the CSP, e.g., multiple copies of the NANP tetramer motif. Some vaccine candidates have included the minor NVDP repeat tetramer. For example, the GSK RTS,S / AS01e (RTS,S) anti-malaria GSK vaccine, recently authorized by the WHO for use in Africa, uses the C-terminal portion of the repeat domain followed by the C-terminal non-repeat region but without the GPI anchor. While the WHO authorization represents a highly significant advance, this vaccine achieves only about30% protection from death, and then only after four immunizations over an 18 month dosing schedule. More recently, the Oxford University R21 / Matrix-M vaccine reported >70% protection under a similar immunization regimen. While this represents an improvement, theneed for annual boosters appears necessary to maintain protection. Clearly, additional improvements are desired to further increase the efficacy of such approved vaccines, the provided disclosure improves the response to the minor repeat sequence, inhibits the competing response to the major repeat sequence, thus improving the efficacy of these vaccines, and also aids in the generation of more protective natural immunity to sporozoite exposure.

[0027] The central repeat region has been reported to exist as linear springs with elastic properties that affect sporozoite motility and cell adhesions (Balaban et al., 2021). The major NANP repeat motif is also recognized as being the immunodominant target of B-cell (i.e., antibody) responses to CSP (see White et al., 2015). In clinical study, anti-NANP titers do associate with protection from infection from parasite challenge (see Ockenhouse et al., 2015). Despite this, no quantitative cut-off level associated with protection has been reported (Ockenhouse et al., 2015; Suscovich et al., 2020), indicating that other immune response specificities also play a role, supported by the observation that antibodies with specificity to the minor NVDP repeat are more neutralizing than antibodies specific to the NANP repeats (Kisalu et al., 2018; Flores-Garcia et al., 2021). The anti-NANP repeat response is thus less effective and serves as a decoy to bias the immune response to an immunodominant but less effective antibody response and thus bias the antibody response away from the NVDP minor repeat and Region 1 (or other non-repeat regions of the CSP) that is more effective in preventing infection by the sporozoite.

[0028] The present disclosure thus aims to decrease production of antibodies specific to the NANP repeat in favor of production of antibodies to the minor NVDP repeat motif and other non-NANP-specific antibody responses. The CIS43 mAb reported by Kisalu et al. binds to a unique “junctional” epitope between the N-terminus and central repeat domains of the CSP, a segment of the CSP that has alternating NANP and NVDP repeats. The conservation of the minor repeats in the N-terminal region of the repeat domain, adjacent to the highly conserved Region 1 sequence is evolutionarily conserved and has therefore been considered to be highly important. Furthermore, Flores-Garcia et al., (2021) reported on antibodies specific to three epitopes specific for repeats containing NPDP, NVDP, or NANP (junction, minor, and major repeat, respectively), and demonstrated that the antibody specific for and binding to the segment incorporating minor NVDP repeat was most protective. Targeting of the antibody epitopes containing the minor NVDP repeats, in the absence of or decreased level of antibody specific to epitopes consisting of NANP repeats, is thus of great interest.

[0029] Furthermore, there is also the possibility for development of a naturally acquired protective immune response. This approach would rely on exposure to the sporozoite stage ofthe parasite, naturally via mosquito infection or injection of sporozoite parasites, by treatment with our drug to decrease anti-NANP responses and allow natural sporozoite infections or whole sporozoite exposure develop a modified immune response to infection that is more protective by virtue of the decreased antibody response specific to NANP. This treatment will be more practical than vaccine immunization in that treatment does not require multiple doses (e.g., the vaccines require up to 4 injections for maximal efficacy), does not require an adjuvant, may be administered subcutaneously or intramuscularly, and results in a broader and more protective anti-parasite immune response. Modification of the immune response will be more effective at preventing infection by the sporozoite stage of the malaria parasite. The present disclosure achieves this desired outcome.EXAMPLES

[0030] The recombinant CSP vaccine used was a full length CSP without the N-terminal leader sequence and C-terminal GPI anchor sequence. All mice (BALB / c) were immunized (Day 1) and boosted (Day 28) intraperitoneally with 10 mcg rCSP absorbed to 100 mcg alum adjuvant (Alhydrogel).

[0031] Our anti-NANP repeat antibody compound, sometimes referred to herein as a construct, or suppressive construct, was made by conjugation of Ac-(NANP)4-Cys-amine (NANPNANPNANPNANP-Cys-amine; SEQ ID 1) to aminodextran (40 kDa molecular weight, 20 amines per dextran) via N-hydroxysuccinimide chemistry using a 24-PEG linker via its terminal cysteine. In the conjugation, the reaction between the aminodextran and the peptide was driven to excess, in the presence of excess peptides. It is believed that all of the amines on the aminodextran were conjugated, and that no remaining -NH2 groups remained on the aminodextran.

[0032] For assessment of antibody responses, the same Ac-(NANP)4-Cys-amine peptide was conjugated to BSA for use as capture antigen in ELISA, by the terminal cysteine via MBS using the same chemistry but a shorter, aromatic linker. Also for assessment of antibody responses, the Region 1 -Repeats synthetic peptide Ac-ADGNPDPNANPNVDPNANPNVDP- Cys-amide [SEQ ID 2] was conjugated to BSA. ELISAs for finer mapping of the immune response to the Region 1 -Junctional region used streptavidin-coated plates and the following biotinylated synthetic peptides:1. Biotin-{mini-PEG}-ADGNPDPNANPNVDP [SEQ ID 3]2. Biotin-{mini-PEG}-ADGNPDPNANP [SEQ ID 4]3. Biotin-{mini-PEG} - -NANPNVDPNANPNVDP [SEQ ID 5]4. Biotin-{mini-PEG} ■NANPNVDP [SEQ ID 6]Treatment and bleed collection schedule are presented in Fig. 2. For treatments on Day 0, groups of animals (n=5) were injected intraperitoneally with either:1) PBS (“No Treatment”);2) 0.25 mg unconjugated (NANP)4 peptide [SEQ ID 1] in simple admixture with 0.25 mg amino-dextran (40 kDa mw, ~20 amino group s / dextran) (“Mock Suppression”); or3) 0.5 mg conjugated compound, the (NANP)4 suppressive construct (“NANP Suppression”).All final volumes injected were 0.5 mL.

[0033] Sera were obtained via retro-orbital bleeding, clotting and clearing, and mixed using equal volumes to create serum pools for rapid antibody analyses. Bleeds were collected on Day -14 (Prebleed), 7 (Bleed 1), 25 (Bleed 2) or 35 (Bleed 3). Collected serum pools were then tested by ELISA for reactivity to various target antigens as described below.

[0034] ELISA was performed by first coating wells with antigens at 0.5 mcg / 100 uL overnight at 4 °C in sodium carbonate coating buffer. Coating antigens consisted of the following and illustrated in Fig. 3: 1) rCSP (recombinant protein produced in E. coli consisting of the entire CSP sequence without signal or GPI anchor sequences); 2) Region 1 -Repeats (synthetic peptide, consisting of the N-terminal repeats post-Region 1 sequence; peptide sequence ADGNPDP(NANPNVDP)2-Cys [Seq ID 2] conjugated to BSA); or 3) NANP repeats (synthetic peptide (NANP)x4Cys [Seq ID 5] conjugated to BSA). The CSP and regions tested are illustrated in Fig 3.

[0035] After coating with antigens, ELISA plates were washed twice with PBS, blocked with 300 uL 1% fish gel in PBS at room temperature for 1 hr, incubated with the pooled serum samples at 1 : 1000 dilution in blocking buffer for 1 hr at room temperature, washed, and incubated with secondary reagent (anti-mouse IgG-HRP) for 1 hr at room temperature. After three final washes with PBS, TMBE color development was added and immediately read to collect kinetic velocity reads, then incubation was continued until 30 minutes after addition of TMBE at which point the reaction was stopped and endpoint reads collected. Results are presented below.

[0036] As presented in the left-hand graphs, the levels of antibody to total rCSP were essentially comparable among the treatment groups. These results indicate that high levels of antibody to total rCSP were generated in all three groups regardless of treatment. Similarly, thelevels of antibody specific to the peptide representing Region 1 - Repeats (center graphs)[Seq ID 2] are comparable amongst the three groups, albeit with slight variations suggesting a lower level of antibody against this peptide in the Mock-Suppression treatment group (Group 2) than in the No Treatment (Group 1) and the NANP-Suppression (Group 3) groups. Antibody responses are shown in Fig. 3.

[0037] Most striking were the antibody levels against the NANP peptide (right-hand graphs) where high levels were observed in the No Treatment group (Group 1), lower levels in the Mock Suppression group (Group 2), and no detectable anti-NANP antibodies in the NANP- Suppression group (Group 3). These differences are notable, given the high levels of antibody found in all three groups as assessed by anti-rCSP levels and suggest that there are important differences in the epitope specificity response to rCSP immunization resulting from the treatments. Most importantly, the levels of anti-NANP are notable not only because the Mock Suppression group (Group 2) had a lower level of antibody compared to No Treatment (Group 1), despite the similar levels of total anti-rCSP antibody, but because the NANP-Suppression group (Group 3) had no detectable anti-NANP antibodies despite the high levels of antibody to rCSP and Region 1. The immune response to rCSP was thus altered by total suppression of antibodies to NANP, and the shifting of immune responses to the other regions of the CSP molecule, e.g., possibly to Region 1 non-repeat N-terminal sequence and other regions of the protein antibodies against which may offer more specific protection.

[0038] Four months after the rCSP boost on Day 28, and without further treatment, the animals were again immunized with rCSP and another test bleed collected 10 days later. The same ELISA was carried out and results are shown in Fig. 4.

[0039] As can be seen all three animal groups generated high levels of antibody to rCSP, as well as to the Region 1 - Repeats synthetic peptide. Only two groups (Group 1 = No Treatment; Group 2 = Mock-Suppressed), however, generated antibodies to the NANP repeats. Group 3 (NANP-Suppression) still did not generate an anti-NANP antibody response. This is a full six months after the single NANP-Suppression treatment, indicating that the animals are rendered incapable of mounting an anti-NANP antibody response.

[0040] In view of the observation that there are no anti-NANP antibodies, we fine-mapped the antibody response to the Region 1 - repeats sequences (Figs. 1 and 5). ELISAs were carried out as above except that the synthetic peptides were N-terminally biotinylated and captured for ELISA using streptavidin-coated plates. Fig. 6 shows the results of ELISA using peptides shown in Fig. 5.

[0041] No reactivity was observed to the smallest repeat peptide tested (Peptide 5: NANPNVDP, equivalent to two tetramer repeats)[Seq ID 6], This was therefore considered to be background for the ELISA and is denoted by the open bar. In contrast, antibodies were detected to the other peptides for Groups 1 (No Treatment) and 2 (Mock Treatment), but Group 3 (NANP-Suppression) showed binding only to Peptide 4 [Seq ID 5] (noted byin Fig. 6). This indicates that these anti-repeat antibodies in Group 3 (NANP-Suppression) are specific for the alternating NANP-NVDP repeats and not to NANP-only repeat sequences. This result and given the lack of antibodies to Peptides 2 [Seq ID 3] and 3 [Seq ID 4], the observed response to Region 1 -Repeats peptide [Seq ID 2] thus shows the antibodies to this region are specific to the minor repeats. Given that there are no detectable antibodies specific to NANP repeats [Seq ID 1] in Group 3 (NANP-Suppression), the antibodies are not the result of crossreaction of such antibodies to NVDP-containing repeat structures but are in fact specific to minor repeat (NVDP) repeats.

[0042] Antibody specific to the NVDP repeats has been demonstrated to be more protective than antibodies specific to NANP repeats (e.g., see Flores-Garcia et al., 2021). By suppressing anti -NANP antibody responses, more protective antibodies specific to the minor NVDP repeats by active immunization or via natural exposure to sporozoites can be achieved. Furthermore, without high levels of anti-NANP antibodies, the action of antibodies specific for the minor NVDP repeats will be unaffected by anti-NANP antibodies.

[0043] In embodiments, suppression of antibodies to malaria CSP (circumsporozoite protein) major repeat peptide epitope (NANPx, which are less protective), and modulate the immune response towards the more protective anti-minor repeat (NVDPx) peptide-containing epitope.

[0044] In embodiments, improved responses to malaria vaccines are provided.

[0045] In embodiments, immunity enhancement for generation of natural immunity in malariaendemic regions are provided.

[0046] In embodiments, suppressing specific antibody response to one epitope among response to several other epitopes, e.g., for suppression of production of antibodies that enhance virus infectivity or that compete with more productive (i.e., neutralizing) antibody responses to malaria is provided.

[0047] In embodiments, it is intended that the NANPx refers to x numbers of NANP peptide consecutive repeats. For example, NANP2 is -NANPNANP; NANP3 is NANPNANPNANP, and so on.

Claims

CLAIMSWhat is claimed is:

1. A compound, having the formula:or a pharmacologically acceptable salt thereof; the scaffold being covalently bound to the epitope; wherein the epitope comprises one or more NANPx peptide groups, wherein x is 2 to 20; and wherein o is 2-70.

2. The compound of claim 1, wherein the scaffold comprises one or more of polymer, dendrimer, peptide-based dendrimer, nanoparticle, dextran, cyclodextrin, a-cyclodextrin, P- cyclodextrin, y-cyclodextrin, dexamine, polyacrylamide, polyvinylpyrolidone, non-ionic synthetic sucrose polymer, carboxymethyl-cellulose, polyvinylalcohol, poly(D-lysine), poly(D-glutamic acid), D-lysine, poly(L-lysine), poly(L-glutamic acid), L-lysine, human serum albumin, gammaglobulin, liposome, or combination thereof.

3. The compound of claim 1, wherein the scaffold comprises dextran.

4. The compound of claim 1, wherein the scaffold comprises a peptide-based dendrimer derived from a D-lysyl-P-alanine (amide) core peptide, subsequent glycine spacer residue addition, and two successive rounds of D-lysine, then glycine addition.

5. The compound of claim 1, wherein the scaffold is valence-restricted.

6. The compound of claim 1, wherein the scaffold is covalently bound to the epitope or a pharmacologically acceptable salt thereof.

7. The compound of claim 1, further comprising one or more linker group between the epitope and the scaffold.

8. The compound of claim 1, wherein the scaffold is non-immunogenic.

8. The compound of claim 1, wherein the scaffold is soluble in physiologically acceptable aqueous solution, buffer, or both.

9. The compound of claim 1, which is soluble in physiologically acceptable aqueous solution, buffer, or both.

10. The compound of claim 1, wherein o is 10-60.

11. The compound of claim 1, wherein o is 12-50.

12. The compound of claim 1, wherein o is 12-30.

13. The compound of claim 1, wherein o is 20.

14. The compound of claim 1, which is prepared by conjugating an Ac-(NANP)4-Cys- amine to an aminodextran via N-hydroxysuccinimide chemistry using a 24-PEG linker via terminal cysteine on the peptide.

15. A method for making the compound of claim 1 , comprising contacting the scaffold with one or more of the epitope, and covalently bonding the scaffold to one of more of the epitope, to form the compound of claim 1.

16. The compound of claim 1, having the formula:or a pharmacologically acceptable salt thereof; wherein A is a linking group; wherein B comprises an NANPx peptide, in which x is 2 to 20; wherein z is 0 or 1; wherein y is 0-20; wherein n is 0 to 50; and wherein o is 2-70.

17. A method for making the compound of claim 16, comprising contacting a scaffold having the following formula comprising one or more covalent-binding reactive group A’ thereon with one or more of an epitope having the following formula comprising a covalent- binding reactive group A” thereon, and covalently bonding, to form the compound of claim 16;or a pharmacologically acceptable salt thereof; wherein m is > o.

18. The compound of claim 1, having the formula:wherein m = 0-100; wherein n is 0 to 50; wherein o is 2-70.

19. The compound of claim 18, wherein the dextran has a molecular weight (MW) of about 10-80 kDa.

20. The compound of claim 18, wherein the dextran has a molecular weight (MW) of about 40 kDa.

21. The compound of claim 18, wherein the dextran has a molecular weight (MW) of about 40 kDa, in which >95% is within the range of 35-45 kDa.

22. The compound of claim 18, wherein m = 0.

23. The compound of claim 18, wherein o = 20.

24. The compound of claim 18, wherein n = 4 to 300.

25. The compound of claim 18, wherein n = 4 to 50.

26. The compound of claim 18, wherein n = 4 to 30.

27. The compound of claim 18, wherein n = 4 to 26.

28. The compound of claim 18, wherein n = 23.

29. A composition, comprising the compound of any claim herein and a pharmaceutically acceptable carrier.

30. The composition of claim 29, further comprising a Malaria CSP vaccine.

31. A method of treating, suppressing or preventing an anti-NANPx antibody response in a subject in need thereof or at risk thereof, comprising administering to said subject the compound or composition of any claim herein.

32. The method of claim 31, wherein the antibody response is an IgG or IgM antibody response.

33. A method of enhancing the effectiveness of a malaria vaccine in a subject, comprising administering the compound or composition of any claim herein to a subject in need thereof.

34. A method of enhancing an anti-malarial immune response in a subject infected with or at risk of infection to malaria, comprising administering the compound or composition of any claim herein to the subject.

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