Controlling antibody specificities in a polyclonal humoral response by epitope tuning

Abstract

In alternative embodiments, provided are chimeric immunogens, and methods for making and using them, including methods for making and obtaining polyclonal antibodies specific for selected epitopes. In alternative embodiments, provided are methods for generating a balanced immune response against a plurality of epitopes present in an antigen comprising immunizing a host with a plurality of polypeptides, wherein each polypeptide comprises one or a subset of said plurality of epitopes. In alternative embodiments, provided are methods for generating a balanced, epitope-specific antibody response in a non-human mammalian host, wherein the immune response comprises generation of host antibodies specifically against (or that specifically bind to) at least one human epitope, and the method comprises administering to the host a sufficient amount of a chimeric or recombinant polypeptide to generate the epitope-specific antibody response.

Description

[0001]PATENT 6363.149133PCT / 20220053-02 CONTROLLING ANTIBODY SPECIFICITIES IN A POLYCLONAL HUMORAL RESPONSE BY EPITOPE TUNING RELATED APPLICATIONS This Patent Convention Treaty (PCT) International Application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Serial No. (USSN) 63 / 617,927, January 5, 2024. The aforementioned application is expressly incorporated herein by reference in its entirety and for all purposes. All publications, patents, patent applications cited herein are hereby expressly incorporated by reference for all purposes. REFERENCE TO ELECTRONIC SEQUENCE LISTING The application contains a Sequence Listing which has been submitted electronically in .XML format and is hereby incorporated by reference in its entirety. Said .XML copy, created on December 21, 2024, is named “6363.149133PCT.xml” and is 16,128 bytes in size. The sequence listing contained in this .XML file is part of the specification and is hereby incorporated by reference herein in its entirety. TECHNICAL FIELD This invention generally relates to immunology and immunoassays. In alternative embodiments, provided are chimeric immunogens, and methods for making and using them, including methods for making and obtaining polyclonal antibodies specific for selected epitopes. In alternative embodiments, provided are methods for generating a balanced immune response against a plurality of epitopes present in an antigen comprising immunizing a host with a plurality of polypeptides, wherein each polypeptide comprises one or a subset of said plurality of epitopes. In alternative embodiments, provided are methods for generating a balanced, epitope- specific antibody response in a non-human mammalian host, wherein the immune response comprises generation of host antibodies specifically against (or that specifically bind to) at least one human epitope, and the method comprises administering to the host a sufficient amount of a chimeric or recombinant polypeptide to generate the epitope-specific antibody response. PATENT 6363.149133PCT / 20220053-02 BACKGROUND Polyclonal antibodies have a diverse reactivity towards multiple epitopes ensuring a robust reaction even in the face of diversity of the target or environmental changes. To obtain polyclonal antibodies, an animal is immunized with a protein, a protein fragment or a mix thereof, after which the humoral immune system selects antibody producing B-cell clones for expansion and maturation. At later stages these B-cells will further diversify through mutagenesis and selection of high affinity immunoglobulin genes. While the immune system has a basic capability to make antibodies against almost any foreign protein, it is known that some epitopes are dominant and that B-cell clones producing antibody that recognizes these “dominant” epitopes will take over the immune response. This means that a standard polyclonal antibody is biased towards some epitopes and may lack reactivity towards other epitopes. In principle, immunization can be by using a single (for example, linear) epitope using a single peptide or a mix of peptides. Peptides may, however, not have the same three dimensional (3D) structure as the protein from which they were derived, thus causing generation of antibodies with less or no affinity to the protein. Peptides (particularly those that are not dominant epitopes) are often too small to elicit an immune response on their own and either need to be built into a larger structure or need to be dependent on co-stimulation with a more immunogenic component to stimulate the immunized animal to generate antibodies against other than the dominant epitopes preferred by the humoral response. It is possible to tolerize against non-selected epitopes using various techniques such as neonatal, drug-induced, masking subtractive immunization or high zone tolerization methods (see for example, US patent 7,598,030; US patent 8,133,744) but tolerization may be a leaky process where antibody clones against non-selected epitopes continuous to show up at some level; and it has been suggested to use combinations to get higher efficiency. In all cases, tolerization means that besides the standard immunization additional procedures are needed as part of the process increasing complexity and cost. Antibody for commercial use is purified from the immunized animal’s serum. Even though total immunoglobulin may be extracted it is frequently necessary to PATENT 6363.149133PCT / 20220053-02 purify the antibody further either by subtracting unwanted reactivity (adsorption purification) or by specifically selecting desired reactivity (affinity purification). It would be advantageous to be able to specify which specific epitopes the polyclonal antibody will recognize without having to add additional steps to the immunization and / or purification procedure. For example, it would be advantageous to eliminate the need for costly and time-consuming adsorption and / or affinity purification steps. SUMMARY In alternative embodiments, provided are methods and compositions for generating a balanced immune response against a plurality of epitopes present in an antigen comprising immunizing a host with a plurality of polypeptides, wherein each polypeptide comprises one or a subset of said plurality of epitopes. In alternative embodiments of methods as provided herein: - a balanced polyclonal antibody response is a polyclonal antibody response comprising (or resulting in the generation of) a plurality of polyclonal antibody populations, each polyclonal antibody population capable of specifically binding to a different epitope on the antigen, and none of the epitopes are substantially dominant over the other epitopes, resulting in a balanced polyclonal antibody response, or a balanced polyclonal serum; - a balanced polyclonal antibody response, or a balanced polyclonal serum, comprises a plurality of antibody populations in approximately similar titers; - no one polyclonal antibody population of the plurality of polyclonal antibody populations has about 5%, 10%, 20% or 30% or more antibodies that any other of the plurality of polyclonal antibody populations in the polyclonal response; - no one polyclonal antibody population of the plurality of polyclonal antibody populations has about 5%, 10%, 20% or 30% greater signal intensity, or signal to noise ratio, or signal rate, than that any other of the plurality of polyclonal antibody populations in the polyclonal response; - none of the epitopes being substantially dominant over the other epitopes means that the binding affinity of each antibody population, or affinity constant Ka and / or dissociation constant Kd to their respective antigen is no more than about 5%, 10%, 20% or 30% higher or lower than all the other antibody populations; PATENT 6363.149133PCT / 20220053-02 - the method further comprises identifying if one or more dominant epitopes are present in the plurality of epitopes; and optionally the one or more dominant epitopes are identified by immunizing a first species with the antigen, and identifying the polyclonal antibody populations generated in the first species and the epitopes to which they bind, and determining if one or more epitopes, or polyclonal antibody populations, are dominant over the other epitopes or polyclonal antibody populations; and optionally a first epitope is considered dominant over the other epitopes if the antibody population that binds to the first epitope has at least about 5%, 10%, 20% or 30% higher titer to the first epitope than the binding affinity of the other antibody populations to their respective epitopes; - the method further comprises engineering a modified antigen by removing one, several or all of the identified one or more dominant epitopes from the antigen, or modifying the structure of the antigen responsible for creating the one or more dominant epitopes such that the one or more dominant epitopes are no longer immunogenic in the first species, or are substantially less immunogenic in the first species, and optionally substantially less immunogenic means at least about 85%, 90% or 95% less immunogenic; - the method further comprises isolating or substantially purifying the polyclonal antibodies of the immunized host; - the antigen comprising a plurality of epitopes comprises a protein, optionally a recombinant, chimeric protein; - the recombinant, chimeric antigen polypeptide comprising a plurality of epitopes comprises: (a) a polypeptide derived from a first species, and (b) at least one epitope comprising a heterologous amino acid sequence or amino acid residue derived from at least a second species, wherein the at least one heterologous amino acid sequence or amino acid residue derived from the second species is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species, and the amino acid sequence of the recombinant, chimeric antigen polypeptide is substantially comprised of amino acid sequence derived from the first species, PATENT 6363.149133PCT / 20220053-02 and the amino acid sequence from the second species when inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species generates, forms or creates at least one new epitope on the polypeptide derived from the first species that is capable of generating a humoral antibody response by the first species specific for the at least one new epitope when the recombinant, chimeric antigen polypeptide is administered to the first species, wherein when the recombinant, chimeric antigen polypeptide is used to generate a humoral immune response from an animal of the first species, the polyclonal antibodies so generated in the first species substantially only specifically bind to the at least one new epitope and do not substantially specifically bind to the polypeptide derived from the first species lacking the at least one new epitope or epitopes created, formed or generated by the at least one heterologous amino acid sequence or amino acid residue derived from the second or additional species inserted into, joined to, created in, or replaced for or substituted for a portion of the polypeptide derived from a first species. - the recombinant, chimeric antigen polypeptide comprising a plurality of epitopes derived from the second species is a homologue of the polypeptide derived from the first species; - the amino acid sequence from the at least one second species is homologous to the first species, and the at least one homologous second species sequence that is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species replaces all or substantially all of a structurally homologous section or portion of the amino acid sequence of the polypeptide derived from the first species; - the amino acid sequence from the at least one second species is homologous to the first species, and the at least one homologous second species sequence that is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species is structurally homologous to an amino acid sequence of the polypeptide derived from the first species; PATENT 6363.149133PCT / 20220053-02 - a homologue of a first species has at least about 25% to 99% sequence identity to its homologue in the second species; - the homologue of the first species has substantially the same secondary and / or tertiary structure as its homologue in the second species; - a homologue of a first species has at least about 25% to 99% sequence identity to its homologue in the second species and has substantially the same secondary and / or tertiary structure as its homologue in the second species; - a homologue of a first species has at least about 50% sequence identity to its homologue in the second species, or a homologue of a first species has at least about 70% sequence identity to its homologue in the second species, or a homologue of a first species has at least about 80% sequence identity to its homologue in the second species, or a homologue of a first species has at least about 90% sequence identity to its homologue in the second species; - the amino acid sequence from the first species and the amino acid sequence from the second species have a Z score of from about 2 to about 8 when aligned using distance matrix alignment; - the amino acid sequence from the first species and the amino acid sequence from the second species have a Z score of at least 8 when aligned using distance matrix alignment; - the polypeptide derived from the first species and its homologue polypeptide from the second species are antibodies; - the polypeptide derived from the first species and the at least one heterologous amino acid sequence derived from the second species are derived from an antibody heavy chain or an antibody light chain; - the antibody heavy chain is an IgM, IgG, IgA or IgE isotype heavy chain, or the light chain is a kappa or a lambda light chain; - the first species is a mammalian species; the second species is a mammalian species; or, the first species is a species of the order Galliformes or the genus Phasianidae and the second species is a mammalian species; or, the first species is a rabbit, a murine species, a sheep, a goat, a pig, a cow a horse or a chicken; and, the second species is a human, or the murine specie is a rat or a mouse; - at least about 80% to about 99% of the amino acid sequence of the recombinant, chimeric antigen polypeptide is amino acid sequence derived from the PATENT 6363.149133PCT / 20220053-02 first species, and / or between about 1% to about 20% of the amino acid sequence of the recombinant, chimeric antigen polypeptide is amino acid sequence derived from the at least one second species; - one, two three, four, five, six, seven or eight or more dominant epitopes are removed or deleted, or are modified such that they are no longer immunogenic in the first species, or are substantially less immunogenic in the first species; - the recombinant, chimeric antigen polypeptide is made by a method further comprising removing one or more new epitopes from the at least one heterologous amino acid sequence or amino acid residue derived from the second or additional species after the one or more new epitopes was inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species; - at least two or more different heterologous amino acid sequences or amino acid residues are inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species; - the at least two or more different heterologous amino acid sequences or amino acid residues are from different animal species, or at least one of the at least two or more different heterologous amino acid sequences or amino acid residues is derived from a human and at least one of the at least two or more different heterologous amino acid sequences or amino acid residues is derived from a non- human or an animal species; - at least one of the heterologous amino acid sequences or amino acid residues comprises an artificial epitope not derived from the at least a second species; - at least one of the heterologous amino acid sequences or amino acid residues comprises an epitope initially derived from the at least a second species that is immunologically silent in the first species (is unable to generate an antibody response in the first species) but is modified to be an immunologically active epitope capable of generating an antibody response against it by the first species; - at least one new epitope in the heterologous amino acid sequences or amino acid residues is modified such that antibodies generated by the first species to the modified new epitope bind less strongly or slower than a comparable unmodified new epitope; PATENT 6363.149133PCT / 20220053-02 - the recombinant, chimeric antigen polypeptide further comprises at least one new epitope derived from an at least second species that is not homologous to the first species, and the at least one new epitope of capable of generating antibodies against it in the first species; - a portion of said plurality of polypeptides comprises an amino acid sequence from the same species as said host and said plurality of epitopes are from a different species than said host, and optionally said host produces antibodies against each of said plurality of epitopes at substantially similar titers; and / or - said portion of said plurality of polypeptides is from rabbits and said plurality of epitopes are from a species other than rabbits, and optionally said portion of said plurality of polypeptides is from a rabbit CDv6 polypeptide. In alternative embodiments, provided are compositions comprising a plurality of polypeptides, wherein each polypeptide comprises one or a subset of said plurality of epitopes present in the antigen. In alternative embodiments of compositions as provided herein: - at least one of said plurality of polypeptides has been engineered to remove one, several or all of the dominant epitopes from the antigen, or has been modified such that one or more dominant epitopes are no longer immunogenic in a first species, or are substantially less immunogenic in a first species; - substantially less immunogenic means at least about 85%, 90% or 95% less immunogenic; - the antigen comprising a plurality of epitopes comprises a protein, optionally a recombinant, chimeric protein; - the recombinant, chimeric antigen polypeptide comprising a plurality of epitopes comprises: (a) a polypeptide derived from a first species, and (b) at least one epitope comprising a heterologous amino acid sequence or amino acid residue derived from at least a second species, wherein the at least one heterologous amino acid sequence or amino acid residue derived from the second species is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species, PATENT 6363.149133PCT / 20220053-02 and the amino acid sequence of the recombinant, chimeric antigen polypeptide is substantially comprised of amino acid sequence derived from the first species, and the amino acid sequence from the second species when inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species generates, forms or creates at least one new epitope on the polypeptide derived from the first species that is capable of generating a humoral antibody response by the first species specific for the at least one new epitope when the recombinant, chimeric antigen polypeptide is administered to the first species, wherein when the recombinant, chimeric antigen polypeptide is used to generate a humoral immune response from an animal of the first species, the polyclonal antibodies so generated in the first species substantially only specifically bind to the at least one new epitope and do not substantially specifically bind to the polypeptide derived from the first species lacking the at least one new epitope or epitopes created, formed or generated by the at least one heterologous amino acid sequence or amino acid residue derived from the second or additional species inserted into, joined to, created in, or replaced for or substituted for a portion of the polypeptide derived from a first species; - the recombinant, chimeric antigen polypeptide comprising a plurality of epitopes derived from the second species is a homologue of the polypeptide derived from the first species; - the amino acid sequence from the at least one second species is homologous to the first species, and the at least one homologous second species sequence that is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species replaces all or substantially all of a structurally homologous section or portion of the amino acid sequence of the polypeptide derived from the first species; - the amino acid sequence from the at least one second species is homologous to the first species, and the at least one homologous second species sequence that is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species is structurally homologous to an amino acid sequence of the polypeptide derived from the first species; PATENT 6363.149133PCT / 20220053-02 - a homologue of a first species has at least about 25% to 99% sequence identity to its homologue in the second species; - the homologue of the first species has substantially the same secondary and / or tertiary structure as its homologue in the second species; - a homologue of a first species has at least about 25% to 99% sequence identity to its homologue in the second species and has substantially the same secondary and / or tertiary structure as its homologue in the second species; - a homologue of a first species has at least about 50% sequence identity to its homologue in the second species; or a homologue of a first species has at least about 70% sequence identity to its homologue in the second species, or a homologue of a first species has at least about 80% sequence identity to its homologue in the second species, or a homologue of a first species has at least about 90% sequence identity to its homologue in the second species; - the amino acid sequence from the first species and the amino acid sequence from the second species have a Z score of from about 2 to about 8 when aligned using distance matrix alignment, or the amino acid sequence from the first species and the amino acid sequence from the second species have a Z score of at least 8 when aligned using distance matrix alignment; - the polypeptide derived from the first species and its homologue polypeptide from the second species are antibodies; - the polypeptide derived from the first species and the at least one heterologous amino acid sequence derived from the second species are derived from an antibody heavy chain or an antibody light chain; - the antibody heavy chain is an IgM, IgG, IgA or IgE isotype heavy chain, or the light chain is a kappa or a lambda light chain; - the first species is a mammalian species; the second species is a mammalian species; or, the first species is a species of the order Galliformes or the genus Phasianidae and the second species is a mammalian species, or the first species is a rabbit, a murine species, a sheep, a goat, a pig, a cow a horse or a chicken; and, the second species is a human, or the murine specie is a rat or a mouse; - at least about 80% to about 99% of the amino acid sequence of the recombinant, chimeric antigen polypeptide is amino acid sequence derived from the first species, and / or between about 1% to about 20% of the amino acid sequence of PATENT 6363.149133PCT / 20220053-02 the recombinant, chimeric antigen polypeptide is amino acid sequence derived from the at least one second species; - one, two three, four, five, six, seven or eight or more dominant epitopes are removed or deleted, or are modified such that they are no longer immunogenic in the first species, or are substantially less immunogenic in the first species; - one or more new epitopes from the at least one heterologous amino acid sequence or amino acid residue derived from the second or additional species has been removed after one or more new epitopes was inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species; - at least two or more different heterologous amino acid sequences or amino acid residues have been inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species; - the at least two or more different heterologous amino acid sequences or amino acid residues are from different animal species; - at least one of the at least two or more different heterologous amino acid sequences or amino acid residues is derived from a human and at least one of the at least two or more different heterologous amino acid sequences or amino acid residues is derived from a non-human or an animal species; - at least one of the heterologous amino acid sequences or amino acid residues comprises an artificial epitope not derived from the at least a second species; - at least one of the heterologous amino acid sequences or amino acid residues comprises an epitope initially derived from the at least a second species that is immunologically silent in the first species (is unable to generate an antibody response in the first species) but is modified to be an immunologically active epitope capable of generating an antibody response against it by the first species; - at least one new epitope in the heterologous amino acid sequences or amino acid residues is modified such that antibodies generated by the first species to the modified new epitope bind less strongly or slower than a comparable unmodified new epitope; - the recombinant, chimeric antigen polypeptide further comprises at least one new epitope derived from an at least second species that is not homologous to the first PATENT 6363.149133PCT / 20220053-02 species, and the at least one new epitope of capable of generating antibodies against it in the first species; - a portion of said plurality of polypeptides comprises an amino acid sequence from the same species as said host and said plurality of epitopes are from a different species than said host, and optionally said host produces antibodies against each of said plurality of epitopes at substantially similar titers; and / or - said portion of said plurality of polypeptides is from rabbits and said plurality of epitopes are from a species other than rabbits, or said portion of said plurality of polypeptides is from the rabbit CDv6 polypeptide, or said portion of said plurality of polypeptides is from the rabbit myoglobin polypeptide. The details of one or more exemplary embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. All publications, patents, patent applications cited herein are hereby expressly incorporated by reference in their entireties for all purposes. DESCRIPTION OF DRAWINGS The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will beprovided by the Office upon request and payment of the necessary fee.The drawings set forth herein are illustrative of exemplary embodiments provided herein and are not meant to limit the scope of the invention as encompassed by the claims. FIG.1 schematically illustrates an exemplary immunization method or scheme using an antigen with many human epitopes, as described in detail in Example 1, below. FIG.2 graphically illustrates the results from an immunization using an exemplary immunization method, as described in detail in Example 1, below. FIG.3A-G graphically illustrate data showing that immunization with single epitope constructs is superior: four different immunizations were compared for reactivity against the five hypothesized epitopes. where: FIG.3A for Ep1, PATENT 6363.149133PCT / 20220053-02 FIG.3B for Ep2, FIG.3C) for Ep3, FIG.3C for Ep4, and FIG.3E for Ep5, FIG.3F schematically illustrates all the epitopes as identified by ELISA, and Cdv6, showing the rabbit lambda light chain constant domain carrying all five human epitopes; and FIG.3G schematically illustrates the chimeric Cdv6 domain with five epitopes labelled 1 through 5 and represented in different colors and highlighted by circles; and to illustrate Epitope 5 the structure was rotated 180 degrees; as described in detail in Example 1, below. FIG.4 illustrates the sequence and structure of Myoglobin (without the Heme group): six chimeric constructs are shown that each carry one human epitope in a rabbit background (rabbit sequence is (SEQ ID NO:10)); the numbers refer to the predicted human epitopes 1-6 (human sequence is (SEQ ID NO:11)); as described in detail in Example 2, below. FIG.5 schematically illustrates an exemplary immunization method or scheme where rabbit groups (five rabbits in each) were immunized with equal protein amount (100 µg / injection) of either native human myoglobin immunogen containing all epitopes (Myo) or a pool mixed of chimeric immunogens (20 µg of each Ep1, Ep2, Ep3, Ep4 and Ep5) with single epitope grafted into rabbit myoglobin cassette; as described in detail in Example 3, below. FIG.6A-C illustrate images of SDS Page and Western blot analysis of purity: FIG.6A illustrates images of SDS and Western blots, in which pure protein samples are seen as a faint band as observed at SDS gel lane 1 (Ep11stpurification, not observed in lane 2 Ep12ndpurification) all other lanes are free from additional bands (lane 3, 4, 5, 6 and 7 corresponds Ep2, Ep3, Ep4, Ep5 and human myoglobin, respectively); and FIG.6B illustrates images of a Western blot showing an anti-E.coli experiment to investigate if impurities related to expression system remains: only lane 1 (Ep11stpurification and lane 6 human myoglobin) contain faint band indicating some impurities; PATENT 6363.149133PCT / 20220053-02 FIG.6C illustrates images of a Western blot experiment for using anti-human myoglobin: only lane 1 has different size from myoglobin a 2ndpurification of Ep1 (lane 7, FIG.6B) remove the extra band and retain Ep1 myoglobin (lane 7, FIG.6C), as described in detail in Example 3, below, as described in detail in Example 3, below. FIG.7 graphically illustrates a UV-vis spectra that was measured to verify that recombinant holo-myoglobin has been expressed and purified: the Soret band around 409 nm indicates that all recombinant myoglobin variants are loaded with heme group, and the data indicate that all recombinant myoglobin are at the met-myoglobin the oxidized state carrying (Fe3+); and the native human myoglobin Soret band is around 418-422 nm indicating that it is either in Oxy-myoglobin or Carboxy- myoglobin state, and Table 1 (see below, Example 3) shows the measurements at five define values, as described in detail in Example 3, below. FIG.8 graphically illustrates the results from an immunization using an exemplary immunization method, as described in detail in Example 3, below. FIG.9 graphically illustrates the structure of Rabbit Myoglobin with the 5 human epitopes replacing the corresponding Rabbit amino acids, as described in detail in Example 3, below. FIG.10 graphically illustrates comparison of group1 and group2 reactivity against various coats: different coats (Epx cassettes grafted with five different epitopes and native human myoglobin (hMyo) were used to evaluate immune respond of the two different immunizations with either a pool of the Epx casettes with the five myoglobin epitopes or native human myoglobin), and EC50 values were estimated by curve fitting. ELISA data (markers) and curve fits (lines), as described in detail in Example 3, below. FIG.11 illustrates Table 2, EC50 values calculated by curve fitting. Two pools of anti-serum from two groups consisting of four rabbits immunized either a mix of epitopes constructs (group1) or native human myoglobin (group2) were used as primary anti-sera in ELISA experiment to evaluate immunization strategies. EC50 values were estimated by curve fitting and used to calculate ratio of group1 / group2 to understand order of improvement, as described in detail in Example 3, below. PATENT 6363.149133PCT / 20220053-02 FIG.12A-F illustrate development of the immune-respons over time: antisera bleeds (bleed 1 --- line and bleed 2 black full line) from four single rabbits (1,2,3 and 4) of both groups (1 and 2, Epx and hMyo, respectively) were analyzed by ELISA to follow immune responds against: FIG.12A, Epitope 1 (Ep1) group 1, FIG.12B, Epitope 1 (Ep1) group 2, FIG.12C Epitope 3 (Ep3), group 1, FIG.12D, Epitope 3 (Ep1) group 2, FIG.12E native human myoglobin (hMyo) carrying all epitopes, group 1, FIG.12F native human myoglobin (hMyo) carrying all epitopes, group 2, and all data were fitted to find EC50 value (Table 3, FIG.13) used for paired t-test to evaluate the two immunization strategies. FIG.13 illustrates Table 3, EC50 values calculated by curve fitting to data, see FIG.12. FIG.14A-F illustrate the development of the immune-response over time; antisera bleeds (bleed 1 --- line and bleed 2 black full line) from four single rabbits (1,2,3 and 4) of both groups (1 and 2, Epx and hMyo, respectively) were analyzed by ELISA to follow immune responds against: FIG.14A Epitope 2 (Ep2), group 1, FIG.14B Epitope 2 (Ep2), group 2, FIG.14C Epitope 4 (Ep4), group 1, FIG.14D Epitope 4 (Ep4), group 2, FIG.14E Epitope 5 (Ep5) group 1, FIG.14F Epitope 5 (Ep5) group 2, all data were fitted to find EC50 value (Table 4, FIG.15) used for paired t-test to compare the two immunization strategies. FIG.15 illustrates Table 4: Antibody titer towards Ep2, Ep4 or Ep5 was not significantly increased between bleed 1 and 2; both the Epx and the hMyo groups were analyzed using a paired t-test; in no case was the EC50 values statistically different from the null hypothesis that the difference between the mean values for bleed 1 and 2 was equal to zero; the test could therefore not confirm that an additional immunization caused any of the two groups to increase titer to epitopes 2, 4 or 5. PATENT 6363.149133PCT / 20220053-02 FIG.16 illustrates Table 5: Immunization with mixture of epitopes (Epx) gave a statistically significant increase in antibody titer to both Ep1 and Ep3; EC50 values used for the statistical analysis are from Table 3 (FIG.13) and 4 (FIG.15); all four animals immunized with Epx responded and the paired t-test demonstrated a statistically significant difference between using Epx and human myoglobin as coat in the ELISA test. *Three out of four rabbits increased titer from bleed 1 to 2, **(n=3; non-responder removed from analysis) and ***only one out of four rabbits increased titer from bleed 1 to 2. FIG.17 graphically illustrates that the higher the current titer the less progress: rabbits immunized with Epx were further analyzed for trends in titer development; EC50 values from bleed 1 for each rabbit versus the ratio of EC50 from bleed 2 to EC50 from bleed 1 was depicted; the trend appears to be a lessor increase, or even a decrease, in titer the higher the current titer; this trend suggests that the difference between antibody titer to the epitopes will diminish over time; Ep1: triangle; Ep2: square; Ep3: cirkel; Ep4: diamond; Ep5: line. FIG.18A-C schematically illustrate how an antibody covers more than one epitope and therefore creates a spatial restriction during binding to epitopes: FIG.18A: Size comparison of human myoglobin (surface representation gray with epitopes in colors, pdb entry: 3rgk) compared to human IgG (heavy chain gray and light chain pale yellow, pdb entry: 1hzh); FIG.18B: Surface representation of human myoglobin illustrate the location of epitope 2 (green), - 3 (sky blue) and – 5(dark red). The spatial arrangement of these three epitopes most likely leads to deprive immune responds due to structural hindrances, which could be solved by immunizing with cassettes carrying single epitope; and FIG.18C: Illustrate one example of structural hindrances where a paratope during binding to epitope 3 potentially create structural hindrances for epitope 2 and epitope 5. Atoms in epitopes are colored according to element. Oxygen (red), Nitrogen (blue) and sulfur (yellow). Like reference symbols in the various drawings indicate like elements. PATENT 6363.149133PCT / 20220053-02 DETAILED DESCRIPTION In alternative embodiments, provided are chimeric immunogens, and methods for making and using them, including methods for making and obtaining polyclonal antibodies specific for selected epitopes. In alternative embodiments, provided are methods for generating a balanced immune response against a plurality of epitopes present in an antigen comprising immunizing a host with a plurality of polypeptides, wherein each polypeptide comprises one or a subset of said plurality of epitopes. In alternative embodiments, methods for generating a balanced immune response as provided herein addresses the problem where skewness of an antibody response to antigen epitopes reduces the usefulness of a polyclonal antibody response for assay development and use. When polyclonal antibodies are used for agglutination reactions, the repertoire should be diverse such that a large and complex structure is formed. If the polyclonal antibody reactivity is skewed towards one or a few epitopes, the agglutination may be less developed, and the sensitivity of an assay based on such agglutination would therefore be reduced. Balanced immune response as provided herein address these issues. Balanced immune response as provided herein also address the problem where immunized animals are selected having a desired response but then these animals have to be discarded at later stages of the immunization program a significant cost is incurred. Also, by using balanced immune response as provided herein it is not necessary to have to manipulate a polyclonal antibody by selectively removing or adding antibody against some epitopes, thus saving both processing time and cost. Problems solved by using balanced immune response methods as provided herein include: - Immunization with native antigen leads to a skewed repertoire of antibody. The consequence of such inferior antibody composition is a loss of signal intensity (less absorbance or light scattering) in agglutination assays. Using balanced response methods as provided herein ensures a more evenly distributed population of antibodies. - Standardization of polyclonal antibody may require selection of the antibody producing animals resulting in increased cost. Using balanced response methods as provided herein ensures a much more even titer in the PATENT 6363.149133PCT / 20220053-02 animals such that most can be utilized, and loss is avoided. - Standardization of polyclonal antibody may require manipulation of the antibody composition by retracting or adding specific reactivity and this results in increased manufacturing time and cost. Using balanced immune response methods as provided herein ensures a much more consistent composition of the polyclonal antibody in most animals eliminating or strongly reducing any need for re-work of the polyclonal antibody. Advantages of using balanced immune response methods as provided herein include for example: ensures that all epitopes can be utilized without mutual interference; ensures that the epitopes all generate antibody at useful levels; and, ensures that most immunized animals can be used to produce antibody, Chimeric or Recombinant Polypeptides and Nucleic Acids In alternative embodiments, provided are chimeric or recombinant polypeptides and methods for making and using them. In alternative embodiments, provided are chimeric or recombinant nucleic acids encoding and expressing polypeptides as provided herein, including expression vehicles containing and expressing these nucleic acids, and cells for containing and expressing these nucleic acids, and also including whole organism expression systems. In alternative embodiments, recombinant polypeptides as provided herein can be prepared and expressed performed using any method known in the art, including for example using whole organisms such as fungi, plants or animals such as mice, as well as cell cultures derived from whole organisms (such as mammalian cells in culture), or using single cell organisms such as algae, fungal, yeast, insect (for example, baculovirus) or bacterial cells. The choice of organism to make (for example, recombinantly generate) a chimeric or recombinant polypeptide and / or nucleic acid as provided herein can depend on several factors, including whether secondary modification such as glycosylation is desired or required, or whether the protein is desired or required to be associated with or inserted in a membrane system (for example, in situ), or if a particular protein folding pattern is desired or required, and / or is a di-sulfide bridge formation is desired or required. In alternative embodiments, a nucleic acid for expressing a chimeric or recombinant polypeptide as provided herein, for example for expression in vitro or in PATENT 6363.149133PCT / 20220053-02 vivo, is contained in an expression vehicle, for example, in an expression cassette, vector, recombinant virus, artificial chromosome, a cosmid or a plasmid. In alternative embodiments, the nucleic acid or expression vehicle expressing a chimeric or recombinant polypeptide as provided herein is administered to an animal (for example, as naked DNA, which can be appropriately formulated) for the purpose of that animal generating a humoral immune response against an epitope in the recombinant polypeptide as provided herein. In alternative embodiments, a protein-coding DNA sequence, which can be in an expression vehicle, is transferred to the organism or cell and placed under control of relevant expression elements such as a transcriptional promoter, an enhancer and / or a polyadenylation signal sequence. In alternative embodiments, a protein sequence as provided herein is processed in a specific cellular organelle(s), and this may require addition of one or more localization signals such as a periplasm localization sequence. In alternative embodiments, a protein-coding DNA sequence (for example, as an expression vehicle) is inserted into a genome (stably or not), or can be alternatively episomal. Recombinant protein expression systems can be transient or permanent. In alternative embodiments, for example to enhance the ability of a given protein to act or function as an antigen or immunogen for immunization purposes, the recombinantly produced protein is purified; for example, the presence of impurities may result in an immunized animal making antibodies against irrelevant targets; and in the presence of too much impurity, formation of high amounts of a desired antibody may be counteracted and removal of reactivity against the impurities from the polyclonal antibody may be time consuming and costly. In alternative embodiments, purification of a protein species is done based on the specific characteristics of the desired protein, for example, purification comprises using hydrophobicity, charge and / or size using chromatographic means such as hydrophobic interaction chromatography (HIC), ion exchange chromatography (IEC) and / or size exclusion chromatography (SEC). In alternative embodiments, specific protein interactions are used for purification purposes, for example, using affinity purification, or lack of specificity of the protein is used to remove other protein species, for example, using absorption purification. In alternative embodiments, antibodies or other protein-specific binding proteins are used for affinity purification and / or absorption purification the protein. PATENT 6363.149133PCT / 20220053-02 In alternative embodiments, when expressing a protein recombinantly, protein sequences are added that allow for specific purification methods such as for example, an epitope tags such as FLAG, hemagglutinin (HA), c-myc, T7, Glu-Glu, ALFA-tag, V5-tag, Myc-tag, HA-tag, Spot-tag, T7-tag and NE-tag; a biotin and streptavidin or avidin system; a polyhistidine affinity tag such as a small HIS-tag (6-8 amino acids) (and optionally using immobilized metal affinity chromatography); an N-terminal glutathione S-transferase (GST) molecules followed by protease cleavage sites; a 43 kDa large Maltose Binding Protein (MBP); an intein-chitin binding domain (intein- CBD) tag; or, a calmodulin binding peptide (CBP) purification system utilizing a C- terminal fragment from muscle myosin light-chain kinase in order to purify proteins of interest from bacteria. This increases the available tools for purification purposes and makes it possible to use standard methods for many different proteins. In some cases, it is desired to remove such purification sequences before performing immunization. This can be achieved by placing a protease site between the purification sequence and the actual protein-encoding sequence, for example, the sequence of a chimeric protein as provided herein. One example is the Tobacco Etch Virus (TEV) protease that upon cleavage of a consensus sequence only leaves an N- terminal Glycine residue. In alternative embodiments, a recombinant protein as provided herein is made in situ in the immunized animal, for example, by modifying cells in an animal to have novel or changed DNA sequences that can code for expression of the recombinant protein, and express and / or secrete those immunogenic proteins. Immunization procedures In alternative embodiments, provided are methods for making antibodies, or for generating or stimulating an immune response, in an animal, for example, in a mammal (for example, a rabbit, a murine species such as a mouse or a rat, a sheep, a goat, a pig, a cow or a horse) or in a species of the genus Phasianidae (for example, a chicken) comprising administering a chimeric or recombinant protein as provided herein. In alternative embodiments, to derive a polyclonal antibody against a protein target, a protein derived from one type of animal (species) is used to give an immune response in another type of animal (species). PATENT 6363.149133PCT / 20220053-02 In alternative embodiments, a chimeric or recombinant protein as provided herein comprising at least one human epitope is used for stimulation of the immune system, for example, for generating a humoral response, in mouse, rat, rabbit, sheep, goat, pig, cow, horse or chicken, and the derived or generated polyclonal antibody or antibodies can specifically recognize the human protein, and can be used to specifically recognize, tag, bind to and / or isolate the human protein from which the at least one human epitope was derived. In alternative embodiments, a protein from any species is used to immunize another species to generate a humoral immune system as long as the protein used for immunization carries at least one modification (for example, at least one one amino acid difference) compared to any homologous protein or protein domain in the species that is being immunized. In alternative embodiments, an adjuvant is also used when administering chimeric or recombinant proteins as provided herein. While the administered chimeric or recombinant protein is the agent directing the immune response to make antibody against specific epitopes expressed by the recombinant protein, an adjuvant mixed with the protein can ensure the immune system is activated; for example, by using a adjuvant the protein is placed in a deposit being released into the body over a longer period. In alternative embodiments, different adjuvants are used, for example, adjuvants based on various principles such as the oil-in-water principle, for example Freund’s Adjuvant is used. In alternative embodiments, protein and adjuvant mixtures are injected into one or more subcutaneous locations. In alternative embodiments, the administration procedure is repeated several times (for example, between about 2 to 10 time) to boost the immune response (the boost phase); and, a high production of polyclonal antibody can be maintained by renewing the immunization at regular but typically longer intervals, for example, additional administrations once every 3 to 16 weeks. Selecting epitopes to be grafted onto a protein backbone In alternative embodiments, provided are recombinant polypeptides comprising a portion of a first polypeptide from a first species and at least one portion of a second polypeptide from a second species, wherein the at least one portion of the second polypeptide is a homologue of the first polypeptide, and wherein the homologous portion of the second polypeptide comprises an epitope which is not PATENT 6363.149133PCT / 20220053-02 present in the first polypeptide. In alternative embodiments, the homologous protein or protein domains exist in the two species of interest. In alternative embodiments, homologous proteins are proteins with a similar 3D structure; when proteins have more than 30% identical protein sequence similarity, they have the same 3-D structure in 90% of cases, and proteins with much less sequence identity may still have similar 3-dimensional structure. In alternative embodiments, the 3-D structural similarity between proteins is assessed using for example, a distance matrix alignment (DALI) and as a rule of thumb a Z-score above 8 indicates homology whereas scores from 2 to 8 represents a grey zone. In alternative embodiments, the backbone protein, or the first polypeptide from a first species, is derived from the species to be immunized (species one) and the epitope sequences are derived from the species that is to be recognized (species two) by the polyclonal antibody. In alternative embodiments, the epitope sequence to be inserted or constructed into the “background” protein, or the first polypeptide from a first species, is derived by: first, the two amino acid sequences are aligned, and differences down to one amino acid residue are highlighted; at least one of (or a plurality of) such amino acid residue differences is selected; and the backbone sequence (species one) is modified by changing the selected, or the plurality of selected, amino acids. In alternative embodiments, after the selected epitope or epitopes have been introduced to the backbone sequence, the derived hybrid (or chimeric) protein is recombinantly expressed, and optionally purified for use in the immunization of species one, and the resulting polyclonal antibodies (or monoclonal antibodies derived from this humoral response) can be applied to recognize the protein in species two. In alternative embodiments, the hybrid or chimeric protein is considered ready for immunization if it can be maintained for at least one day in solution in a concentration of at least about 50 µg per mL. Further quality control can optionally be performed before immunization via immunological and / or biochemical tests or by spectroscopic examination (for example, circular dichroism) to substantiate that the protein structure is correct. PATENT 6363.149133PCT / 20220053-02 In alternative embodiments, when the polyclonal antibody is to be used for assays working on intact protein, for example, assays such as ELISA, turbidimetry and CLIA assays, it may be an advantage to include further steps, for example: - the two amino acid sequences are aligned, and differences down to one amino acid are highlighted; - the differences are highlighted on the 3D structure of the protein or domain; - differences residing in surface exposed areas are identified; - at least one of such surface exposed differences is selected; and / or, - the backbone sequence (species one) is modified by changing the selected amino acids to those of species two. In some cases, the 3D structure of the protein or domain may be unknown and the second and third steps cannot be applied; instead, in alternative embodiments, a series of hybrid proteins with different epitope sequences are examined until the desired antibody is derived. Exemplary applications of making and using chimeric proteins as provided herein Prevention of undesired antibody reactivity or characteristics In alternative embodiments, recombinant polypeptides as provided herein are used for, or methods as provided herein further comprise: - increasing specificity for one homologous protein species out of a family, for example, by avoiding epitopes in the applied backbone sequence from species two that exist in other members of the protein family (in species two) such that the immune reaction will be aimed, or more focused, at the remaining epitopes, that are more unique for the selected protein species; - increasing specificity for one domain out of many in a protein; this can be done by removing epitopes that exist in other domains of the protein family (of species two) such that the immune reaction will be aimed at the remaining epitopes that are more unique for the selected domain; - increasing cooperativity of the polyclonal antibody composition for a given application; one example is to obtain reactivity against a sub-set of epitopes to cause fast and efficient cross-binding in a turbidimetric reaction, and another example is to create a polyclonal antibody that can cooperate with a monoclonal antibody in an assay such as ELISA or CLIA (for example, by removing the epitope recognized by the monoclonal antibody); PATENT 6363.149133PCT / 20220053-02 - preventing undesired characteristics of a polyclonal antibody, for example, by selectively removing epitopes from the species two sequence, such that subtypes of paratopes on the antibody are avoided, for example, where key characteristics such as antibody isoelectric point (pI) and hydrophobicity may be influenced or controlled to give desirable characteristics when interacting with other materials (one example is interaction with plastic surfaces); - obtaining a higher degree of control over the manufacturing process of polyclonal antibody such that it is more standardized from batch to batch; one example is to remove one or more immune dominant epitope from the species two sequence until a more consistent reactivity toward minor epitopes is achieved in the immunized animals; another example is to eliminate or remove from the species two polypeptide the weakest epitopes to avoid the more variable response to such elements; and / or - reduce reactivity (for example, the reaction speed) towards a given protein by removing some epitopes and / or reducing the antibody affinity by using (or inserting into the species two sequence) a modified epitope or epitopes, where this is useful for applications such as wide range turbidimetric assays. Addition of desired reactivity or characteristics In alternative embodiments, recombinant polypeptides as provided herein are used for, or methods as provided herein further comprise: - multi-species reactivity such that the same antibody can be used for, for example, diagnostics of both humans and animal species; this antibody can be made by inserting additional epitopes into the species one backbone, or by combining or fusing different recombinant proteins with different epitope characteristics, or with different newly inserted epitopes; - multi-protein reactivity such that all or a selected sub-set of a protein family are recognized by a polyclonal antibody; this can be achieved by adding or inserting epitopes into the species one backbone that are different between the family members or by combining hybrid proteins that have different versions of the selected epitopes in the immunization mixture; - multi-domain reactivity such that all or a selected sub-set of a domain type are recognized by a polyclonal antibody; this can be achieved by adding epitopes into the species one backbone that are different between the domains or by combining PATENT 6363.149133PCT / 20220053-02 hybrid domains that have different versions of the selected epitopes in the immunization mixture; - reactivity towards epitopes that do not give a primary response; by using a series of modified epitopes, it is possible to overcome lack of a primary response towards a given epitope as has been shown for development of vaccine against virus, for example, by Escolano, et al., 2016, Cell 166, 1445–1458; this approach with sequential immunization can also be used for production of polyclonal antibody; and / or - enhancing desired characteristics of a polyclonal antibody, for example, by selectively removing epitopes from the species two sequence such that subtypes of paratopes on the antibody are avoided; key characteristics such as antibody pI and hydrophobicity may be influenced or controlled to give desirable characteristics when interacting with other materials, for example, when interacting with plastic surfaces. In alternative embodiments, humoral immunity is the immune response involving transformation of B cells into plasma cells that produce and secrete antibodies to a specific antigen. In alternative embodiments, an epitope, also known as antigenic determinant, is the part of an antigen that is recognized by an antibody. In alternative embodiments, a paratope, also called an antigen-binding site, is a part of an antibody which recognizes and binds to an antigen. In alternative embodiments, the isoelectric point (pI) is the pH of a solution at which the net charge of a protein becomes zero; at solution pH that is above the pI, the surface of the protein is predominantly negatively charged, and therefore like- charged molecules will exhibit repulsive forces. Vaccines and Vaccination In alternative embodiments, provided are vaccine formulations comprising chimeric or recombinant polypeptides, nucleic acids encoding them, including DNA- and RNA-protein encoding molecules (for example, protein-encoding mRNA), or nucleic acid expression vehicles as provided herein, and / or cells as provided herein. In alternative embodiments, vaccine formulations as provided herein comprise or further comprise an adjuvant or an incomplete adjuvant, or a pharmaceutically acceptable excipient, wherein optionally the pharmaceutically acceptable excipient comprises a sterile buffer, saline or water. PATENT 6363.149133PCT / 20220053-02 In alternative embodiments, chimeric or recombinant polypeptides, nucleic acids (such as protein-encoding RNA) encoding them or nucleic acid expression vehicles as provided herein are formulated in liposomes, for example, as liposome delivery vehicles having a polycationic lipid composition (for example, cationic liposomes) and / or liposomes having a cholesterol backbone conjugated to polyethylene glycol, where exemplary cationic liposome compositions comprise or are manufactured using: N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA) and cholesterol, N-[1-(2,3-dioleoyloxy)propyl]-N,N,N- trimethylammonium chloride (DOTAP) and cholesterol, 1-[2-(oleoyloxy)ethyl]-2- oleyl-3-(2-hydroxyethyl)-imidazolinium chloride (DOTIM) and cholesterol, dimethyldioctadecylammonium bromide (DDAB) and cholesterol, and combinations thereof. For example, in alternative embodiments the protein-encoding nucleic acid can be a DNA encoding one or more immunogenic peptides or proteins, and the DNA can be carried in an expression vehicle such as a viral vector, for example an adenovirus vector such as an Ad5 or adeno-associated vector (AAV). In alternative embodiments, recombinant adenoviruses as used in vaccines as provided herein can be as described in U.S. patent application no. US 20200399323 A1, which describes for example recombinant adenoviruses including a deletion in or of the E1 region or any deletion that renders the virus replication-defective, for example, the replication- defective virus can include a deletion in one or more of the E1, E3, and / or E4 regions; or, can be as described in U.S. patent application no. US 20190382793 A1, which described how to make recombinant adenoviruses for gene therapy. In alternative embodiments, the protein-encoding nucleic acid can be an RNA, for example, mRNA, which can be formulated in a lipid formulation or a liposome and injected for example intramuscularly (IM), for example using formulations and methods as described in U.S. patent application no. US 20210046173 A1, which describes delivering to a subject (for example, via intramuscular administration) an immunogenic composition that comprises a RNA (for example, mRNA) that comprises an open reading frame (ORF) that comprises (or consists of, or consists essentially of) an immunogenic or antigenic sequence as provided herein; wherein optionally the RNA (or the DNA-carrying expression vehicle) is formulated in a liposome, or a lipid nanoparticle (LNP), or nanoliposome, that comprises: non- PATENT 6363.149133PCT / 20220053-02 cationic lipids comprise a mixture of cholesterol and DSPC, or a PEG-lipid, or PEG- modified lipid, or LNP, or an ionizable cationic lipid; or a mixture of (13Z,16Z)-N,N- dimethyl-2-nonylhenicosa-12,15-dien-1-amine, cholesterol, DSPC, and PEG-2000 DMG. In alternative embodiments, the PEG-lipid is 1,2-Dimyristoyl-sn-glycerol methoxypolyethylene glycol (PEG-DMG), PEG-disteryl glycerol (PEG-DSG), PEG- dipalmetoleyl, PEG-dioleyl, PEG-distearyl, PEG-diacylglycamide (PEG-DAG), PEG- dipalmitoyl phosphatidylethanolamine (PEG-DPPE), or PEG-1,2- dimyristyloxlpropyl-3-amine (PEG-c-DMA), or, the PEG-lipid is PEG coupled to dimyristoylglycerol (PEG-DMG). In alternative embodiments, chimeric or recombinant polypeptides, nucleic acids encoding them or nucleic acid expression vehicles as provided herein are formulated with or administered with an adjuvant, which for example can comprise: aluminum hydroxide or mineral oil, a stimulator of immune responses such as lipid A, Bortadella pertussis or Mycobacterium tuberculosis derived proteins; for example, Freund's Incomplete Adjuvant and Complete Adjuvant (Difco Laboratories, Detroit, Mich.); Merck Adjuvant 65 (Merck and Company, Rahway, N.J.); AS-2 (GlaxoSmithKline, Philadelphia, Pa.); aluminum salts such as aluminum hydroxide gel (alum) or aluminum phosphate; salts of calcium, iron or zinc; an insoluble suspension of acylated tyrosine; acylated sugars; cationically or anionically derivatized polysaccharides; polyphosphazenes; biodegradable microspheres; monophosphoryl lipid A and quil A. Cytokines, such as GM-CSF, interleukin-2, -7, - 12, and other like growth factors, may also be used as adjuvants. In alternative embodiments, chimeric or recombinant polypeptides, nucleic acids encoding them or nucleic acid expression vehicles as provided herein are administered in one or multiple dosage regimens. In alternative embodiments, chimeric or recombinant polypeptides, nucleic acids encoding them or nucleic acid expression vehicles as provided herein, or vaccines as provided herein, are administered at a dosage of between about 100 µg and about 1 mg; or at a dose comprising between about 50 µg and 500 µg; or between about 1mg and about 10 mg. The vaccine can be administered for example in a single dose, or in two, three, four or five or more doses. In one embodiment, the two doses are administered at a one- or two-week intervals. PATENT 6363.149133PCT / 20220053-02 In alternative embodiments, chimeric or recombinant polypeptides, nucleic acids encoding them or nucleic acid expression vehicles as provided herein, or vaccines as provided herein, are administered via intradermal, transdermal, intranasal (for example, by intranasal drops or intranasal aerosol delivery), intramuscular, subcutaneous or sublingual routes. In alternative embodiments, chimeric or recombinant polypeptides, nucleic acids encoding them or nucleic acid expression vehicles as provided herein, or vaccines as provided herein, are administered using a syringe, a pneumatic injector or a jet injection device. Products of manufacture and Kits Provided are products of manufacture and kits for practicing methods as provided herein, including for example nucleic acids such as expression vehicles for expressing chimeric or recombinant polypeptides as provided herein, or chimeric polypeptides as provided herein, or cells expressing chimeric or recombinant polypeptides as provided herein, or vaccine formulations as provided herein, for example, comprising chimeric or recombinant polypeptides as provided herein; and optionally, products of manufacture and kits can further comprise instructions for practicing methods as provided herein. Any of the above aspects and embodiments can be combined with any other aspect or embodiment as disclosed here in the Summary, Figures and / or Detailed Description sections. As used in this specification and the claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Unless specifically stated or obvious from context, as used herein, the term “or” is understood to be inclusive and covers both “or” and “and”. Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. About (use of the term “about”) can be understood as within 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12% 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from the context, all numerical values provided herein are modified by the term “about.” PATENT 6363.149133PCT / 20220053-02 Unless specifically stated or obvious from context, as used herein, the terms “substantially all”, “substantially most of”, “substantially all of” or “majority of” encompass at least about 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, or more of a referenced amount of a composition. The entirety of each patent, patent application, publication and document referenced herein hereby is incorporated by reference. Citation of the above patents, patent applications, publications and documents is not an admission that any of the foregoing is pertinent prior art, nor does it constitute any admission as to the contents or date of these publications or documents. Incorporation by reference of these documents, standing alone, should not be construed as an assertion or admission that any portion of the contents of any document is considered to be essential material for satisfying any national or regional statutory disclosure requirement for patent applications. Notwithstanding, the right is reserved for relying upon any of such documents, where appropriate, for providing material deemed essential to the claimed subject matter by an examining authority or court. Modifications may be made to the foregoing without departing from the basic aspects of the invention. Although the invention has been described in substantial detail with reference to one or more specific embodiments, those of ordinary skill in the art will recognize that changes may be made to the embodiments specifically disclosed in this application, and yet these modifications and improvements are within the scope and spirit of the invention. The invention illustratively described herein suitably may be practiced in the absence of any element(s) not specifically disclosed herein. Thus, for example, in each instance herein any of the terms "comprising", "consisting essentially of", and "consisting of" may be replaced with either of the other two terms. Thus, the terms and expressions which have been employed are used as terms of description and not of limitation, equivalents of the features shown and described, or portions thereof, are not excluded, and it is recognized that various modifications are possible within the scope of the invention. Embodiments of the invention are set forth in the following claims. The invention will be further described with reference to the examples described herein; however, it is to be understood that the invention is not limited to such examples. PATENT 6363.149133PCT / 20220053-02 EXAMPLES Unless stated otherwise in the Examples, all recombinant DNA techniques are carried out according to standard protocols, for example, as described in Sambrook et al. (2012) Molecular Cloning: A Laboratory Manual, 4th Edition, Cold Spring Harbor Laboratory Press, NY and in Volumes 1 and 2 of Ausubel et al. (1994) Current Protocols in Molecular Biology, Current Protocols, USA. Other references for standard molecular biology techniques include Sambrook and Russell (2001) Molecular Cloning: A Laboratory Manual, Third Edition, Cold Spring Harbor Laboratory Press, NY, Volumes I and II of Brown (1998) Molecular Biology LabFax, Second Edition, Academic Press (UK). Standard materials and methods for polymerase chain reactions can be found in Dieffenbach and Dveksler (1995) PCR Primer: A Laboratory Manual, Cold Spring Harbor Laboratory Press, and in McPherson at al. (2000) PCR - Basics: From Background to Bench, First Edition, Springer Verlag, Germany. Example 1: Exemplary methods Materials and methods Epitope Selection Human epitopes were identified based on sequence alignment. The identified epitopes were used to design chimeric variants reacting against human and not rabbit Lambda Free Light Chain Constant Domain. Protein expression and Purification Constructs encoding chimeric variants of λ-FLC were ordered at GENSCRIPT® and cloned into expression pET22b(+) used for E.coli expression. CdV6 fused to ferritin was order at GENEART and cloned into pTT5 vector used for HEK cell expression. The E.coli λ-FLC constructs were designed with an N-terminal His-tag followed by a TEV cleavage site to separate the His-tag from the constant domain. Recombinant rabbit λ-FLC constant domain grafted with all or single epitopes were expressed periplasmic using E.coli strain BL21 (Invitrogen™). The ferritin fused CdV6 construct was designed without His-tag. PATENT 6363.149133PCT / 20220053-02 When expressed in E.coli the lysogeny broth medium containing recombinant protein was dialyzed against binding buffer (20 mM Na2HPO4, 150 mM NaCl, pH 7.4) before recombinant protein were immobilized by affinity chromatography (IMAC) using a His-tag column (Cytivia). Immobilized protein was washed with wash buffer (20 mM Na2HPO4, 1 M NaCl, 20 mM Imidazole, pH 7.4) with at least 15 column volumes, and eluted with elution buffer (20 mM Na2HPO4, 150 mM NaCl, 500 mM Imidazole, pH 7.4). His-tagged recombinant protein was dialyzed into cleavage buffer (20 mM Tris, 150 mM NaCl, pH 8) before adding TEV protease (0.2 mg / mL, final concentration) supplemented with 2 mM reduced L-Glutathione (final concentration). The cleavage reaction was left overnight at + 4˚C. To separate cleaved recombinant protein from His-tag, TEV protease, and un-cleaved recombinant protein the mixture was loaded onto His-tag column, and flow through was collected and contain the untagged recombinant protein. The sample was further purified using size exclusion chromatography (SEC) SUPERDEX 75™ Prep Grad (GE Healthcare) with binding buffer as eluent. When expressed in HEK cells standard protocols was followed. The secreted protein was purified by concentrating the supernatant and loaded directly to an S400 sephacryl column (Cytiva). This was done repeatedly until high purity was achieved. Protein concentration determination Protein concentrations were calculated from A280 absorbances and sequence specific extension coefficients calculated using ProtParam (Expasy.org). SDS-PAGE and Western blotting Protein purity was followed by SDS-PAGE using pre-caste NUPAGE™ 4- 12 % Bis-Tris gels (Invitrogen™). All protein samples were loaded with SDS sample buffer (350 mM Tris.HCL, 357 mM Sodium dodecyl sulfate, 44.6 % Glycerol, 179 µM Bromophenol blue, pH 6.8) and carried out in a MES SDS running buffer (NOVEX®). Gels were stained with SimplyBlue™ (Invitrogen™). For Western blotting NUPAGE™ 4-12 % Bis-Tris gels (Invitrogen™) and MES SDS running buffer (NOVEX®) were used to separate the proteins. The electro blotting was carried out at 30 V for 1 hour, and proteins were transferred to PVDF membrane (BioRad) in PATENT 6363.149133PCT / 20220053-02 Western blot buffer (25 mM Tris, 0.192 M Glycine and ethanol 25.3 %). The blotting was followed by a blocking step using blocking buffer (50 mM Tris-HCL, 0.5 M NaCl, 0.5 % Tween20, pH 9.0). Blocked PVDF membrane containing transferred protein was incubated for 1 hour (minimum) with primary pAb (rabbit anti-E.coli diluted 1000x) and up-to overnight at +4˚C with shaking. Before membrane was incubated for 1 hour with secondary pAb (swine anti-rabbit) the membrane was washed 4 x 10 min with blocking buffer. After incubation with secondary pAb membrane was again washed 4 x 10 min with blocking buffer and incubated 20 min with DAB (diaminobenzidine) and substrate. Antigen preparation and immunization Based on SDS-PAGE and Western blotting analysis of fractions from SEC purification, a highly pure antigen sample was produced. The antigen sample constitutes an equal amount of five chimers each carrying a single epitope (EP1, Ep2, Ep3, Ep4 or Ep5) or a single chimeric domain carrying all epitopes (CdV6) or CdV6- Ferrtin to elicit immune responds. Antigen samples were mixed in equally amounts (1:1) with Freunds incomplete adjuvant (FIA) immediately prior to immunizing three- month-old rabbits subcutaneously. Sera were collected before immunization and each second week after last up-immunization. Sera were preserved by adding sodium azide (NaN3) to a final concentration of 15 mM and stored a 4˚C. Enzyme-linked immunosorbent assay (ELISA) All antigens, that is the chimeric variants of λ-FLC, were diluted to 1 µg / mL with coating buffer (10 mM Na2HPO4, 145 mM NaCl, 0.1 % Tween-20, pH 7.2). The dilutions were used to coat 96 well plates overnight at 4 ˚C. All primary pAb (IgG fractions or anti-sera) were diluted with 5% skimmed milk in 3-fold series starting from 100 µg / mL or 200 times diluted. Plates were washed using wash buffer (10 mM Na2HPO4, 500 mM NaCl, 0.1 % Tween-20, pH 7.2) and incubated 1 hour with primary pAb at room temperature with agitation. Followed by wash with wash buffer, and incubation with secondary pAb (HRP goat-antirabbit) diluted in 5 % skimmed milk to 10 µg / mL for 1 hour with agitation. Finally, plates were washed with washing buffer and developed for 5 minutes after adding TMB (DAKO S1599) 100 µL per well. Reactions were stopped by adding 100 µL 0.5 M H2SO4 to each reaction well. PATENT 6363.149133PCT / 20220053-02 Results were detected by ELISA reader using SOFTMAX™ 6.2.1 with detection wavelengths 450 nm and 650 nm. This example demonstrates exemplary protocols and methods as provided herein. In alternative embodiments, methods as provided herein utilize chimeric antigens made recombinantly. In alternative embodiments, constructs are made carrying single epitopes to immunize with a pool of single epitope antigens. Figure 1 illustrates an exemplary immunization method using an antigen with many human epitopes. CDv6 is the rabbit Lambda Free Light Chain (FLC) Constant Domain modified to carry epitopes at five positions, i.e., CDV6 is a chimeric domain derived from the constant domain of rabbit lambda free light chain and grafted with human epitopes specific for free light chain, and epitopes numbered 1 through 5 are single epitopes grafted onto the rabbit scaffold constant domain: CdV6 (SEQ ID NO:1) GQPAVTPTVTLFPPSSEELKDNKATLVCLISDFYPGAVTVNWKADGNSVTQGVETTK PSKQSNNKYAASSYLSLSANQWKSYQSVTCQVTHEGHTVEKSLAPTECS (SEQ ID NO:1) The rabbit amino acid sequence for the constant domain from (rabbit) lambda free light chain is (SEQ ID NO:2): GQPAVTPSVILFPPSSEELKDNKATLVCLINDFYPRTVKVNWKADGNSVTQGVDTTQ PSKQSNNKYAASSFLSLSANQWKSYQSVTCQVTHEGHTVEKSLAPAECS (SEQ ID NO:2) The human amino acid sequence for the constant domain from lambda free light chain is (SEQ ID NO:3): GQPKANPTVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADGSPVKAGVETTK PSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS (SEQ ID NO:3) In Figure 1, the Ep1 to Ep5 antigens are similar to CDv6 but each with only one human epitope: Epitope 1 (SEQ ID NO:4) GQPAVTPTVTLFPPSSEELKDNKATLVCLISDFYPRTVKVNWKADGNSVTQGVDTTQ PSKQSNNKYAASSFLSLSANQWKSYQSVTCQVTHEGHTVEKSLAPAECS Epitope 2 (SEQ ID NO:5) GQPAVTPSVILFPPSSEELKDNKATLVCLINDFYPRTVKVNWKADGNSVTQGVETTQ PSKQSNNKYAASSYLSLSANQWKSYQSVTCQVTHEGHTVEKSLAPAECS PATENT 6363.149133PCT / 20220053-02 Epitope 3 (SEQ ID NO:6) GQPAVTPSVILFPPSSEELKDNKATLVCLINDFYPRTVKVNWKADGNSVTQGVDTTK PSKQSNNKYAASSFLSLSANQWKSYQSVTCQVTHEGHTVEKSLAPAECS Epitope 4 (SEQ ID NO:7) GQPAVTPSVILFPPSSEELKDNKATLVCLINDFYPRTVKVNWKADGNSVTQGVDTTQ PSKQSNNKYAASSFLSLSANQWKSYQSVTCQVTHEGHTVEKSLAPTECS Epitope 5 (SEQ ID NO:8) GQPAVTPSVILFPPSSEELKDNKATLVCLINDFYPGAVTVNWKADGNSVTQGVDTTQ PSKQSNNKYAASSFLSLSANQWKSYQSVTCQVTHEGHTVEKSLAPAECS CDv6 immunization is done with 100 µg per rabbit or 50 µg per rabbit in case of CdV6-Ferritin, and the Ep1-5 single epitope chimeric antigens are immunized as a pool, using 20 µg of each chimer. Thus, in both cases the animal receives 100 µg antigen per immunization round. The frequency of immunization and the adjuvant formulation were the same for the two groups. The two schemes gave a different result, as illustrated in Figure 2, which graphically illustrates the results from immunization with CDv6 (blue circles) or a pool of Ep1-5 (orange squares). Polyclonal antibody was compared using ELISA.96 wells plates were coated with Ep chimeric protein. The coated plates were then challenged with primary antibody derived from immunized rabbits in a three-fold dilution series. Secondary antibody carrying HRP was used with TMB as substrate and absorbance reported. The structure of the Constant Domain with the human epitopes is shown in the bottom right side. The domain is also represented in each of the five titration diagrams with the relevant epitope shown in color corresponding to the epitope color in the bottom right structure. Immunization with CDv6 resulted in antibody recognizing epitopes 1,2,4, and 5 but the antibody titer against epitope 3 was low. In contrast, the pool of Ep1-5 gave a high titer against all five epitopes. Empirically one can expect to see some epitopes being immunodominant. They somehow incur a substantial response and numerous antibodies with low Kd (high affinity) are found. In this case, we see another cause for skewness in the antibody response. One epitope is inferior to the other 4 epitopes and is not inducing the desired amount of antibody. The same epitope, however, is effective in inducing an antibody response when presented as a single epitope antigen even though the other four epitopes were PATENT 6363.149133PCT / 20220053-02 applied simultaneously. This shows that the epitope in the context of the protein domain is immunologically fully active. We therefore foresee that by using methods as provided herein it is possible to induce production of antibody to all or most epitopes by immunization with a pool of chimeric antigens that each only carry a single epitope. We also foresee that by using methods as provided herein it is possible to make chimeric antigen carrying several epitopes if they are of similar strength. Such multi-epitope antigens are an advantage because a lower total number of antigens can be used per immunization. We propose the term Epitope-Tuning for making optimal combinations of single epitope and / or selected multi-epitope combinations carried by chimeric antigen. Some epitopes carry moieties that can be post translationally modified (PTM) such as sulfhydryl groups or phosphorylation sites. By using single epitope constructs, it is possible to apply specific modifications (for example, de-phosphorylated) and immunize with all relevant versions. This way the polyclonal antibody is equally specific for all versions of PTM epitopes. When it is important to solely obtain polyclonal antibody recognizing the selected (human) epitopes, then the epitopes are inserted in the context of (rabbit) antigen or antigen domains that are homologous between species such as is the case for immunoglobulin in human and rabbit. If using non-homologous parts or parts not derived from the species to be immunized (rabbit), then these must be selected to not interfere with the (human) epitopes. Furthermore, even when the ability to induce antibody by the selected epitopes is not hampered by such parts then they will also induce antibody. These non-epitope recognizing antibodies must be ensured not to interfere with the downstream applications of the polyclonal antibody. Antibodies are progressed by mechanisms in the animal’s adaptive immune response. Antigens are taken up and small fragments are presented in MHC protein. Binding by immature immunoglobulin located on B-cells leads to clonal expansion. Ensuing mutation and selection leads to high affinity antibody production. These processes appear to be competitive allowing some epitopes to induce high amounts of antibody while suppressing induction by others. PATENT 6363.149133PCT / 20220053-02 A construct with CdV6 (in bold) fused to rabbit ferritin via a linker (italicized) has also been used as immunogen (rabbit ferritin moiety underlined): CdV6-Linker-Ferritin (SEQ ID NO:9) GQPAVTPTVTLFPPSSEELKDNKATLVCLISDFYPGAVTVNWKADGNSVTQGVETTK PSKQSNNKYAASSYLSLSANQWKSYQSVTCQVTHEGHTVEKSLAPTECSGGGGSGGG GSGGGGSGGGGSGGGGSMTSQIRQNYSPEVEAAVNHLVNLHLRASYTYLSLGFYFDR DDVALEGVSHFFRELAEEKREAAERLLKMQNQRGGRALFQDVQKPSQDEWGKTLNAM LSGPQASLGEYLFERLTLKHD FIG.3A-G illustrate data showing that immunization with single epitope constructs is superior: four different immunizations were compared for reactivity against the five hypothesized epitopes (Ep1 (FIG.3A), Ep2 (FIG.3B), Ep3 (FIG.3C), Ep4 (FIG.3C) and Ep5 (FIG.3E)) by ELISA. Cdv6: the rabbit lambda light chain constant domain carrying all five human epitopes (FIG.3F). Cdv6 + oval: Cdv6 co- immunized with ovalbumin. Cdv6-Fer: Ferritin fused with Cdv6 and folded into the 24 mer structure. Epx + oval: Five Cdv constructs each carrying one of the human epitopes mixed with ovalbumin. The wells were coated with the indicated epitope specific versions of Cdv and incubated with anti-serum from one of the four different immunizations. Anti-rabbit antibody labelled with HRP was used for visualization purposes. FIG.3G schematically illustrates the Cdv6 domain used as antigen with all five epitopes labelled 1 through 5, and highlighted by circles. Table 6. CdV6 + Epx + CdV6- CdV6 Oval Oval Fer Ep1 0,15 0,28 0,17 1,90 Ep2 0,24 0,44 0,23 0,30 Ep3 5,48 4,81 0,31 0,40 Ep4 0,16 0,44 0,20 0,53 Ep5 0,17 0,34 0,23 30,24* mean 1,24 1,26 0,23 6,67 SD 2,37 1,98 0,05 13,19 CV(%) 191,17 157,26 22,87 197,63 PATENT 6363.149133PCT / 20220053-02 Table 6. Immunization with multiple single epitope constructs provides for substantial reactivity to all epitopes. The EC50 values were derived from data in Figure 3A-E. The average EC50 value was calculated for each immunogen. *Note that Ep5 EC50 value has been estimated by curve fitting. Example 2: Exemplary methods and construction of chimeric constructs This example demonstrates exemplary chimeric constructs, each carrying one human epitope in a rabbit context. Myoglobin is an oxygen carrier in heart musculature consisting of 154 amino acids and a heme-group. It is a marker for cardiac disease, when the concentration in serum goes up it is an early warning sign. The myoglobin protein is homologous between human and rabbit but there are 16 amino acid (aa) differences. Human myoglobin is predicted to contain six epitopes as indicated in Figure 4. Six chimeric constructs, each encoding rabbit myoglobin into which one of the six human epitopes has been introduced are generated and the encoded antigens are obtained as described herein. Rabbits are immunized with a pool containing each of the 6 antigens encoded by the constructs. A balanced immune response against each of the 6 human epitopes in the antigens is obtained. No substantial immune response against the rabbit sequences in the antigens is observed. In contrast, when rabbits are immunized with antigens in which three to five human epitopes have been introduced into the rabbit myoglobin protein, a more variable response with antibodies directed more towards some human epitopes than others are observed. Immunization with the chimeric constructs does not elicit a substantial immune response to native rabbit myoglobin. rabbit myoglobin (see FIG.4) (SEQ ID NO:10) MGLSDAEWQLVLNVWGKVEADLAGHGQEVLIRLFHTHPETLEKFDKFKHLK SEDEMKASEDLKKHGNTVLTALGAILKKKGHHEAEIKPLAQSHATKHKIPVK YLEFISEAIIHVLHSKHPGDFGADAQAAMSKALELFRNDIAAQYKELGFQG (SEQ ID NO:10) human myoglobin (epitope locations, bolded, are also indicated in FIG.4, see also circles in FIG.3G) (SEQ ID NO:11) PATENT 6363.149133PCT / 20220053-02 MGLSDGEWQLVLNVWGKVEADIPGHGQEVLIRLFKGHPETLEKFDKFKHLK SEDEMKASEDLKKHGATVLTALGGILKKKGHHEAEIKPLAQSHATKHKIPVK YLEFISECIIQVLQSKHPGDFGADAQGAMNKALELFRKDMASNYKELGFQG (SEQ ID NO:11) Example 3: Exemplary Methods to produce a more diverse polyclonal antibody We here show a method for obtaining a strong and levelled polyclonal antibody response. The core of the method is to immunize with a mix of chimer constructs that each only presents one single human epitope although it in some cases may be possible to reduce the number of chimeric constructs by adding more than one epitope to each chimer. Example 1 above concerns the constant domain from human λ free light chain (λ-FLC). A protein domain strongly structured by a so-called β-sheet fold. The other example is Myoglobin. This protein is structured by α-helical elements and has a highly different primary sequence. In Example 1 above, the epitopes are in the hidden surface, thus covered in intact IgG. By immunizing with the constant domain grafted with all epitopes (CdV6, gray triangle FIG.3) reactivity is observed for all epitopes. However, epitope 3 is recognized to a much lesser extent compared to the other epitopes (Ep1, Ep2, Ep4 and Ep5). The immunogenicity of the single domain was relatively low as seen from numbers of rabbits responding to the immunization. By co-immunizing CdV6 with ovalbumin we obtain a strong immune respond in all rabbits. However, the diversity of the polyclonal antibody was not improved as seen from FIG.3 (CdV6 + Oval, blue circles). The data indicates that one or more epitopes is dominant and sufficient for the rabbit to clear the immunogen. Thus, not raising clones against the weaker epitope. To test this hypothesis, we immunize with five chimeric proteins utilizing the rabbit cassette grafted with epitope Ep1, Ep2, Ep3, Ep4 or Ep5. The epitopes are shown on the 3D structure in FIG.3F. However, it should be underlined that we are using five different proteins, each carrying only one human epitope as illustrated in Figures 1 and 5. A high antibody respond was also seen towards Ep3 when the mix of five chimeric constructs was applied as illustrated in Figure 3. PATENT 6363.149133PCT / 20220053-02 In the second example with myoglobin described below, all epitopes are solvent exposed, but some epitopes could possibly be suppressed due to steric hindrance (Figure 18). Immunizing with a pool as described in Example 1 above would circumvent any steric hindrance. Two rabbit groups were immunized either with a pool of a single epitope (Epx) chimers or human native myoglobin carrying all epitopes (hMyo) as illustrated in Figure 5. To stimulate immune responds both groups were co-immunized with ovalbumin. Materials and Methods Epitope Selection Human epitopes were identified based on sequence alignment. The identified epitopes were used to design chimeric variants that can direct antibody production towards human and not rabbit Myoglobin. Protein expression and Purification All constructs encoding chimeric variants of myoglobin were ordered at GENSCRIPT® and cloned into expression pET3c (Novagen). The myoglobin constructs were designed without any tags. Recombinant myoglobin was expressed according to (Bianchi, M. et al. Protein Expr Purif.2003 Jun;29(2):265-71). Briefly by adding heme precursor 5-aminolevulinic acid (ALA) to lysogeny broth (L.B.) medium the bacterium biosyntheses of heme which allows myoglobin to be expressed in it is holo-form. Holo-myoglobin was expressed cytoplasmic for 20 hours. Cells were sonicated and cell debris spun down prior to protein purification. Supernatant was dialyzed against binding buffer (20 mM Tris pH 7.4) and immobilized on anion exchange column (Cytivia). After washing with binding buffer myoglobin was eluted with increasing sodium chloride concentration. The eluted samples were further purified using SEC (SUPERDEX 75™ Prep Grad [GE Healthcare]) using run buffer (20 mM Na2HPO4, 150 mM NaCl, pH 7.4) PATENT 6363.149133PCT / 20220053-02 Protein concentration determination Protein concentrations were calculated from A280 absorbances and sequence specific extension coefficients calculated using ProtParam (Expasy.org). UV-vis spectrum was recorded to verify holo-myoglobin as indicated by the Soret band. SDS-PAGE and Western blotting Protein purity was followed by SDS-PAGE using pre-caste NUPAGE™ 4- 12 % Bis-Tris gels (Invitrogen™). All protein samples were loaded with SDS sample buffer (350 mM Tris.HCL, 357 mM Sodium dodecyl sulfate, 44.6 % Glycerol, 179 µM Bromophenol blue, pH 6.8) and carried out in a MES SDS running buffer (NOVEX®). Gels were stained with SimplyBlue™ (Invitrogen™). For Western blotting NUPAGE™ 4-12 % Bis-Tris gels (Invitrogen™) and MES SDS running buffer (NOVEX®) were used to separate the proteins. The electro blotting was carried out at 30 V for 1 hour, and proteins were transferred to PVDF membrane (BioRad) in Western blot buffer (25 mM Tris, 0.192 M Glycine and ethanol 25.3 %). The blotting was followed by a blocking step using blocking buffer (50 mM Tris-HCL, 0.5 M NaCl, 0.5 % Tween20, pH 9.0). Blocked PVDF membrane containing transferred protein was incubated for 1 hour (minimum) with primary pAb (rabbit anti-E.coli diluted 1000x) and up-to overnight at +4˚C with shaking. Next, the membrane was washed 4 x 10 min with blocking buffer and subsequently incubated for 1 hour with secondary pAb (swine anti-rabbit). After incubation with secondary pAb, the membrane was washed 4 x 10 min with blocking buffer and then incubated 20 min with DAB (diaminobenzidine) and substrate. Antigen preparation and immunization Based on SDS-PAGE and Western blotting analysis of fractions from SEC purification a highly pure antigen sample was produced. Only fractions without any visual impurities were included in the final antigen sample. The antigen sample contained an equal amount of five chimeric domains, each carrying a single epitope (EP1, Ep2, Ep3, Ep4 or Ep5), or a single domain carrying all epitopes (native human myoglobin [Lee Bioscience]) to elicit immune responds. Antigen samples were mixed in equally amount (1:1) with Freunds incomplete adjuvant (FIA) just before immunizing rabbits subcutaneously. Sera were collected before immunization and PATENT 6363.149133PCT / 20220053-02 each second week after last up-immunization. Sera were preserved by adding sodium azide (NaN3) to a final concentration of 15 mM and stored a 4˚C. Enzyme-linked immunosorbent assay (ELISA) All antigens made of chimeric variants of myoglobin were diluted to 3 µg / mL. The dilutions were used to coat 96 well plates overnight at 4 ˚C. All primary pAb (anti-sera) were diluted with 5% skimmed milk in 3-fold series starting from 100 µg / mL or 200 times diluted. Plates were washed using wash buffer (10 mM Na2HPO4, 500 mM NaCl, 0.1 % Tween-20, pH 7.2) and incubated 1 hour with primary pAb at room temperature with agitation. Followed by wash with wash buffer, and incubation for 1 hour, with agitation, with secondary pAb (HRP goat-antirabbit) diluted in 5 % skimmed milk to 10 µg / mL Finally, plates were washed with washing buffer and developed for 5 minutes after adding TMB (DAKO S1599) 100 µL per well. Reactions were stopped by adding 100 µL 0.5 M H2SO4 to each reaction well. Results were detected by ELISA reader using SOFTMAX™ 6.2.1 with detection wavelengths 450 nm and 650 nm. Table 1 (for Example 3), for FIG.7 Myo-Epi-23.3039 14.6648 6.4390 2.4657 0.6773 Myo-Epi-31.8778 7.5554 3.8249 1.6887 0.4262 Myo-Epi-43.8443 16.2388 7.5785 3.2650 0.7891 Myo-Epi-56.4383 12.7584 18.1938 9.5352 1.7450 Human myo6.7390 13.5412 19.2939 10.0808 1.8568 Results Summary, discussion and conclusion for Myoglobin Results Summary Antibody titer to human myoglobin is higher in animals immunized with a mix of epitopes (Epx) than with human myoglobin (FIG.10 and 11). The superior induction of antibody production was both apparent when using human myoglobin and any of the five chimeric constructs as bait in the ELISA test. This indicates that the chimer immunization principle is working for myoglobin as well as for the structurally and sequence-wise very different constant lambda light chain domain. We compared the difference in titer between bleed 2 and bleed 1 for each rabbit (Figures 12 and 14) and applied the EC50 values (Figures 13 and 15) to PATENT 6363.149133PCT / 20220053-02 conduct a paired t-test (Figure 16)). This showed that an additional round of Epx immunization increased the response towards epitope 1 (p=0.03) and possibly epitope 3 (p=0.06) but neither native human myoglobin nor epitopes 2, 4 and 5 demonstrated an increase in the mean EC50 value. Immunization with native human myoglobin did not raise the overall levels of antibody to any of Ep1 – Ep5 or human Myoglobin according to the paired t-test. In FIG.17 the EC50 value of bleed one is depicted on the x-axis and the EC50 ratio between bleed 2 and 1 on the y-axis. Only data for the Epx immunization group is shown. An inverse relationship is apparent, suggesting that a high EC50 value predicts less increase in (or even diminished) titer. Overall, it seems likely that titer towards Ep1 will continue to raise if the Epx immunization schedule is continued as the titer is low and was shown to increase from bleed 1 to 2. It is harder to predict the outcome of titer to Ep3. On the one hand, the mean of the four rabbits probably did increase from bleed 1 to 2, but on the other hand the titer is high making further increase less likely according to FIG.17) Rabbit no 3 is unusual in having a very high titer towards Ep2, 4 and 5 (FIG. 15) that goes down from bleed 1 to 2. This extreme example may point to an overshoot effect where very high titer levels are reduced in time. It is also interesting because it shows that the chimer immunization can induce very high titers towards multiple epitopes in the same rabbit. It is further noteworthy that while the titer to epitopes 2, 4 and 5 goes down from bleed 1 to 2 then the titer to Ep1 and Ep3 increases (FIG.13). It seems like rabbit no 3 is magnifying a general trend towards a levelling-out of the titer to the five epitopes. Figure 11 shows that at bleed 2, the immunization with a mix of epitopes (Epx) is giving a very similar ELISA titer to Ep2-5 but a lower titer to Ep1. At the same time, our most certain prediction is that the titer to Ep1 will increase. Together this suggests that the response to the five epitopes equalizes over time. Discussion Immunization of an animal eventually leads to selection of antibody producing plasma cells that are stored in the bone marrow for future use. Each plasma cell only express one specific antibody sequence, and the polyclonal antibody is a product of expression from multiple plasma cell clones. PATENT 6363.149133PCT / 20220053-02 However, this process sometimes shows dominance of certain antibody clones making the resulting polyclonal antibody somewhat restricted in titer to the epitopes on the target antigen. We speculate that for myoglobin, the overlap between especially epitope 2, 3 and 5 (FIG.18) may be one reason for such a restriction. If a B-cell clone recognizing epitope 3 is highly functional (for instance if the antibody has high affinity and expression is highly efficient), then antigen may be bound and blocked before other B-cell clones binds to the antigen. This would effectively block further induction of these clones. At least one other mechanism should be considered, namely the uniqueness of the epitope. All else equal, an epitope that makes evolution of a highly specific antibody more likely is reversely more likely to induce high titer of antibody. This leads to rapid removal of the antigen which may hinder evolution of alternative antibodies that binds to other epitopes. Again, this would lead to less diversity in the polyclonal antibody. Immunization with the chimer constructs effectively uncouples the involved epitopes making them act independently. Unique epitopes would still effectively be targeted but without negative consequences for less attractive epitopes. Functional paratope in antibody has been found to be overpopulated with aromatic residues (Tyr, Trp and to lesser extent Phe) in the antibody-antigen contact region (H. Peng, K.H. Lee, J. Jian, A. Yang, Origins of specificity and affinity in antibody– protein interactions, Proc. Natl. Acad. Sci. U.S.A.111 (26) E2656-E2665,2014). In the contact region aromatic residues interact mainly with the backbone atoms and side chains of the epitope through relatively weak noncovalent interactions. These weak interactions are a sum of face to edge or parallel π-stacking, cation- or anion- π, hydrogen bond donors through aromatic π system, alkyl carbons through C-H-π interaction sulfur-arene interaction. As all these interactions are fairly weak and it is the sum of many that accounts for binding energies resulting in kd ~1 nM. The aromatic residues are often surrounded by hydrophilic residues (Ser, Thr, Asp and Asn). In contrast to paratopes, where some pattern can be found, epitopes are much more difficult. However, analysis of antibody-antigen interaction interface has found that hydrophobic interaction only contribute minor to the driving force in antibody-antigen PATENT 6363.149133PCT / 20220053-02 recognition (H. Peng, K.H. Lee, J. Jian, A. Yang, Origins of specificity and affinity in antibody–protein interactions, Proc. Natl. Acad. Sci. U.S.A.111 (26) E2656- E2665,2014). In the case of Myoglobin, where Ep3 induces a rapid high-level response while Ep1 induces a much slower evolving response, it is interesting to note that the Ep1 epitope bears the characteristics of a weakly inducing epitope. The Pro, Leu and Ala can be classified as only weakly immunogenic as they are hydrophobic residues. Furthermore, Leu is packed into the core, and thereby not solvent exposed, preventing side chain interaction. Conclusion We conclude that during early immunization, the method of immunizing rabbits with a mix of recombinant myoglobin chimers, where each chimer only carries one human epitope, increases the production of antibody towards the selected epitopes faster than seen when using human myoglobin as antigen. The data supports that immunization with a pool of epitopes (Epx) is superior to cause production of antibody against human epitopes present in the mix. Importantly, these data derived early during immunization shows that while Ep2-5 initially can induce highly expressed antibodies, this will later stagnate or even decline whereas the titer to Ep1 continuous to raise and thereby levels out the polyclonal response. References Example 1 Angeletti et al., Outflanking immunodominance to target subdominant broadly neutralizing epitopes.2019. PNAS pages 13474–13479, vol.116 no.27 Immunology and Evolution of Infectious Disease. Chapter 6: Immunodominance within hosts. Steven A. Frank. Princeton University Press (2002). Price et al. Light-scattering immunoassay of specific proteins: a review. (1983). Ann Clin Biochem 20 pages 1-14. References Example 3 Bianchi, M. et al. Protein Expr Purif.2003 Jun;29(2):265-71 H. Peng, K.H. Lee, J. Jian, A. Yang, Origins of specificity and affinity in antibody–protein interactions, Proc. Natl. Acad. Sci. U.S.A.111 (26) E2656- E2665,(2014) PATENT 6363.149133PCT / 20220053-02 A number of embodiments of the invention have been described. Nevertheless, it can be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims

PATENT 6363.149133PCT / 20220053-02 CLAIMS WHAT IS CLAIMED IS:

1. A method for generating a balanced immune response against a plurality of epitopes present in an antigen comprising immunizing a host with a plurality of polypeptides, wherein each polypeptide comprises one or a subset of said plurality of epitopes present in the antigen.

2. The method for generating a balanced immune response of claim 1, wherein a balanced polyclonal antibody response is a polyclonal antibody response comprising (or resulting in the generation of) a plurality of polyclonal antibody populations, each polyclonal antibody population capable of specifically binding to a different epitope on the antigen, and none of the epitopes are substantially dominant over the other epitopes, resulting in a balanced polyclonal antibody response, or a balanced polyclonal serum.

3. The method for generating a balanced immune response of claim 1, wherein a balanced polyclonal antibody response, or a balanced polyclonal serum, comprises a plurality of antibody populations in approximately similar titers.

4. The method for generating a balanced immune response of claim 2, wherein no one polyclonal antibody population of the plurality of polyclonal antibody populations has about 5%, 10%, 20% or 30% or more antibodies that any other of the plurality of polyclonal antibody populations in the polyclonal response.

5. The method for generating a balanced immune response of claim 2, wherein no one polyclonal antibody population of the plurality of polyclonal antibody populations has about 5%, 10%, 20% or 30% greater signal intensity, or signal to noise ratio, or signal rate, than that any other of the plurality of polyclonal antibody populations in the polyclonal response.

6. The method for generating a balanced immune response of claim 2, wherein none of the epitopes being substantially dominant over the other epitopes means that the binding affinity of each antibody population, or affinity constant KaPATENT 6363.149133PCT / 20220053-02 and / or dissociation constant Kd to their respective antigen is no more than about 5%, 10%, 20% or 30% higher or lower than all the other antibody populations.

7. The method for generating a balanced immune response of claim 1, further comprising identifying if one or more dominant epitopes are present in the plurality of epitopes.

8. The method for generating a balanced immune response of claim 7, wherein the one or more dominant epitopes are identified by immunizing a first species with the antigen, and identifying the polyclonal antibody populations generated in the first species and the epitopes to which they bind, and determining if one or more epitopes, or polyclonal antibody populations, are dominant over the other epitopes or polyclonal antibody populations.

9. The method for generating a balanced immune response of claim 7, wherein a first epitope is considered dominant over the other epitopes if the antibody population that binds to the first epitope has at least about 5%, 10%, 20% or 30% higher titer to the first epitope than the binding affinity of the other antibody populations to their respective epitopes.

10. The method for generating a balanced immune response of claim 8, further comprising engineering a modified antigen by removing one, several or all of the identified one or more dominant epitopes from the antigen, or modifying the structure of the antigen responsible for creating the one or more dominant epitopes such that the one or more dominant epitopes are no longer immunogenic in the first species, or are substantially less immunogenic in the first species.

11. The method for generating a balanced immune response of claim 10, wherein substantially less immunogenic means at least about 85%, 90% or 95% less immunogenic.PATENT 6363.149133PCT / 20220053-02 12. The method for generating a balanced immune response of claim 1, further comprising isolating or substantially purifying the polyclonal antibodies of the immunized host.

13. The method for generating a balanced immune response of claim 1, wherein the antigen comprising a plurality of epitopes comprises a protein, optionally a recombinant, chimeric protein.

14. The method for generating a balanced immune response of claim 13, wherein the recombinant, chimeric antigen polypeptide comprising a plurality of epitopes comprises: (a) a polypeptide derived from a first species, and (b) at least one epitope comprising a heterologous amino acid sequence or amino acid residue derived from at least a second species, wherein the at least one heterologous amino acid sequence or amino acid residue derived from the second species is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species, and the amino acid sequence of the recombinant, chimeric antigen polypeptide is substantially comprised of amino acid sequence derived from the first species, and the amino acid sequence from the second species when inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species generates, forms or creates at least one new epitope on the polypeptide derived from the first species that is capable of generating a humoral antibody response by the first species specific for the at least one new epitope when the recombinant, chimeric antigen polypeptide is administered to the first species, wherein when the recombinant, chimeric antigen polypeptide is used to generate a humoral immune response from an animal of the first species, the polyclonal antibodies so generated in the first species substantially only specifically bind to the at least one new epitope and do not substantially specifically bind to the polypeptide derived from the first species lacking the at least one new epitope orPATENT 6363.149133PCT / 20220053-02 epitopes created, formed or generated by the at least one heterologous amino acid sequence or amino acid residue derived from the second or additional species inserted into, joined to, created in, or replaced for or substituted for a portion of the polypeptide derived from a first species.

15. The method for generating a balanced immune response of claim 14, wherein the recombinant, chimeric antigen polypeptide comprising a plurality of epitopes derived from the second species is a homologue of the polypeptide derived from the first species.

16. The method for generating a balanced immune response of claim 14, wherein the amino acid sequence from the at least one second species is homologous to the first species, and the at least one homologous second species sequence that is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species replaces all or substantially all of a structurally homologous section or portion of the amino acid sequence of the polypeptide derived from the first species.

17. The method for generating a balanced immune response of claim 14, wherein the amino acid sequence from the at least one second species is homologous to the first species, and the at least one homologous second species sequence that is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species is structurally homologous to an amino acid sequence of the polypeptide derived from the first species.

18. The method of claim 14, wherein a homologue of a first species has at least about 25% to 99% sequence identity to its homologue in the second species.

19. The method of claim 14, wherein the homologue of the first species has substantially the same secondary and / or tertiary structure as its homologue in the second species.PATENT 6363.149133PCT / 20220053-02 20. The method of claim 18 and 19, wherein a homologue of a first species has at least about 25% to 99% sequence identity to its homologue in the second species and has substantially the same secondary and / or tertiary structure as its homologue in the second species.

21. The method of claim 14, wherein a homologue of a first species has at least about 50% sequence identity to its homologue in the second species.

22. The method of claim 21, wherein a homologue of a first species has at least about 70% sequence identity to its homologue in the second species.

23. The method of claim 12, wherein a homologue of a first species has at least about 80% sequence identity to its homologue in the second species.

24. The method of claim 12, wherein a homologue of a first species has at least about 90% sequence identity to its homologue in the second species.

25. The method of any one of claims 14 to 26, wherein the amino acid sequence from the first species and the amino acid sequence from the second species have a Z score of from about 2 to about 8 when aligned using distance matrix alignment.

26. The method of claims 25, wherein the amino acid sequence from the first species and the amino acid sequence from the second species have a Z score of at least 8 when aligned using distance matrix alignment.

27. The method of any one of claims 14 to 26, wherein the polypeptide derived from the first species and its homologue polypeptide from the second species are antibodies.

28. The method any one of claims 14 to 27, wherein the polypeptide derived from the first species and the at least one heterologous amino acid sequencePATENT 6363.149133PCT / 20220053-02 derived from the second species are derived from an antibody heavy chain or an antibody light chain.

29. The method of claim 28, wherein the antibody heavy chain is an IgM, IgG, IgA or IgE isotype heavy chain, or the light chain is a kappa or a lambda light chain.

30. The method of any one of claims 14 to 29, wherein: the first species is a mammalian species; the second species is a mammalian species; or, the first species is a species of the order Galliformes or the genus Phasianidae and the second species is a mammalian species.

31. The method of any one of claims 14 to 30, wherein the first species is a rabbit, a murine species, a sheep, a goat, a pig, a cow a horse or a chicken; and, the second species is a human.

32. The method of claim 31, wherein the murine specie is a rat or a mouse.

33. The method of any one of claims 14 to 32, wherein at least about 80% to about 99% of the amino acid sequence of the recombinant, chimeric antigen polypeptide is amino acid sequence derived from the first species, and / or between about 1% to about 20% of the amino acid sequence of the recombinant, chimeric antigen polypeptide is amino acid sequence derived from the at least one second species.

34. The method of any one of claims 14 to 33, wherein one, two three, four, five, six, seven or eight or more dominant epitopes are removed or deleted, or are modified such that they are no longer immunogenic in the first species, or are substantially less immunogenic in the first species.

35. The method of any one of claims 14 to 34, wherein the recombinant, chimeric antigen polypeptide is made by a method further comprising removing one or more new epitopes from the at least one heterologous amino acid sequence orPATENT 6363.149133PCT / 20220053-02 amino acid residue derived from the second or additional species after the one or more new epitopes was inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species.

36. The method of any one of claims 14 to 35, wherein at least two or more different heterologous amino acid sequences or amino acid residues are inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species.

37. The method of claim 36, wherein the at least two or more different heterologous amino acid sequences or amino acid residues are from different animal species.

38. The method of claim 37, wherein at least one of the at least two or more different heterologous amino acid sequences or amino acid residues is derived from a human and at least one of the at least two or more different heterologous amino acid sequences or amino acid residues is derived from a non-human or an animal species.

39. The method of any of claims 36 to 38, wherein at least one of the heterologous amino acid sequences or amino acid residues comprises an artificial epitope not derived from the at least a second species.

40. The method of any of claims 36 to 39, wherein at least one of the heterologous amino acid sequences or amino acid residues comprises an epitope initially derived from the at least a second species that is immunologically silent in the first species (is unable to generate an antibody response in the first species) but is modified to be an immunologically active epitope capable of generating an antibody response against it by the first species.

41. The method of any of claims 36 to 40, wherein at least one new epitope in the heterologous amino acid sequences or amino acid residues is modifiedPATENT 6363.149133PCT / 20220053-02 such that antibodies generated by the first species to the modified new epitope bind less strongly or slower than a comparable unmodified new epitope.

42. The method any of claims 14 to 41, wherein the recombinant, chimeric antigen polypeptide further comprises at least one new epitope derived from an at least second species that is not homologous to the first species, and the at least one new epitope of capable of generating antibodies against it in the first species.

43. The method any of the preceding claims, or of any of claims 1 to 42, wherein a portion of said plurality of polypeptides comprises an amino acid sequence from the same species as said host and said plurality of epitopes are from a different species than said host.

44. The method any of the preceding claims, or of any of claims 1 to 43, wherein said host produces antibodies against each of said plurality of epitopes at substantially similar titers.

45. The method any of the preceding claims, or of any of claims 1 to 44, wherein said portion of said plurality of polypeptides is from rabbits and said plurality of epitopes are from a species other than rabbits.

46. The method any of the preceding claims, or of any of claims 1 to 45, wherein said portion of said plurality of polypeptides is from the rabbit CDv6 polypeptide.

47. The method any of the preceding claims, or of any of claims 1 to 45, wherein said portion of said plurality of polypeptides is from the rabbit myoglobin polypeptide.

48. A method for screening for or identifying the presence of an antibody or a plurality of antibodies specific for a polypeptide antigen in a sample, comprising: (a) providing a sample, wherein optionally the sample comprises a biological fluid, and optionally the biological fluid comprises a serum or blood sample or an acites fluid, and optionally the serum, blood sample or acites fluid is harvested from aPATENT 6363.149133PCT / 20220053-02 non-human animal that has been immunized with a plurality of polypeptides, wherein each of the plurality of polypeptide comprises one or several epitopes present in the antigen; (b) providing a solid or semi-solid surface having affixed thereto one, several or all of the plurality of polypeptides, wherein optionally the solid or semi-solid surface is a solid or semi-solid surface of a bead, well, biochip, microchip, column, tube or capillary tube, or microfluidic chip or device; (c) contacting the sample with or passing the sample over the solid or semi- solid surface under conditions wherein the antibody or the plurality of antibodies specific for a polypeptide antigen is or are specifically bound by the one, several or all of the plurality of polypeptides; and (d) identifying whether, or not, an antibody or a plurality of antibodies specific for the polypeptide antigen has specifically bound to the one, several or all of the plurality of peptides affixed to the solid or semi-solid surface.

49. The method for screening of claim 48, further comprising isolating the antibody or the plurality of antibodies specific for the polypeptide antigen by eluting the antibody or the plurality of antibodies specifically bound to the plurality of polypeptides from the solid or semi-solid surface.

50. The method for screening of claim 48 or 49, wherein the plurality of polypeptides comprises the plurality of polypeptides used in the method for generating a balanced immune response as set forth in any of claims 1 to 47.

51. A composition comprising a plurality of polypeptides, wherein each polypeptide comprises one or a subset of said plurality of epitopes present in the antigen.

52. The composition of claim 51, wherein at least one of said plurality of polypeptides has been engineered to remove one, several or all of the dominant epitopes from the antigen, or has been modified such that one or more dominant epitopes are no longer immunogenic in a first species, or are substantially less immunogenic in a first species.PATENT 6363.149133PCT / 20220053-02 53. The composition of claim 52, wherein substantially less immunogenic means at least about 85%, 90% or 95% less immunogenic.

54. The composition of any one of claims 51-53 wherein the antigen comprising a plurality of epitopes comprises a protein, optionally a recombinant, chimeric protein.

55. The composition of claim 53, wherein the recombinant, chimeric antigen polypeptide comprising a plurality of epitopes comprises: (a) a polypeptide derived from a first species, and (b) at least one epitope comprising a heterologous amino acid sequence or amino acid residue derived from at least a second species, wherein the at least one heterologous amino acid sequence or amino acid residue derived from the second species is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species, and the amino acid sequence of the recombinant, chimeric antigen polypeptide is substantially comprised of amino acid sequence derived from the first species, and the amino acid sequence from the second species when inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species generates, forms or creates at least one new epitope on the polypeptide derived from the first species that is capable of generating a humoral antibody response by the first species specific for the at least one new epitope when the recombinant, chimeric antigen polypeptide is administered to the first species, wherein when the recombinant, chimeric antigen polypeptide is used to generate a humoral immune response from an animal of the first species, the polyclonal antibodies so generated in the first species substantially only specifically bind to the at least one new epitope and do not substantially specifically bind to the polypeptide derived from the first species lacking the at least one new epitope or epitopes created, formed or generated by the at least one heterologous amino acid sequence or amino acid residue derived from the second or additional species insertedPATENT 6363.149133PCT / 20220053-02 into, joined to, created in, or replaced for or substituted for a portion of the polypeptide derived from a first species.

56. The composition of claim 55, wherein the recombinant, chimeric antigen polypeptide comprising a plurality of epitopes derived from the second species is a homologue of the polypeptide derived from the first species.

57. The composition of claim 55, wherein the amino acid sequence from the at least one second species is homologous to the first species, and the at least one homologous second species sequence that is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species replaces all or substantially all of a structurally homologous section or portion of the amino acid sequence of the polypeptide derived from the first species.

58. The composition of claim 55, wherein the amino acid sequence from the at least one second species is homologous to the first species, and the at least one homologous second species sequence that is inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species is structurally homologous to an amino acid sequence of the polypeptide derived from the first species.

59. The composition of claim 55, wherein a homologue of a first species has at least about 25% to 99% sequence identity to its homologue in the second species.

60. The composition of claim 55, wherein the homologue of the first species has substantially the same secondary and / or tertiary structure as its homologue in the second species.

61. The composition of claims 59 and 60, wherein a homologue of a first species has at least about 25% to 99% sequence identity to its homologue in the second species and has substantially the same secondary and / or tertiary structure as its homologue in the second species.PATENT 6363.149133PCT / 20220053-02 62. The composition of claim 55, wherein a homologue of a first species has at least about 50% sequence identity to its homologue in the second species.

63. The composition of claim 62, wherein a homologue of a first species has at least about 70% sequence identity to its homologue in the second species.

64. The composition of claim 62, wherein a homologue of a first species has at least about 80% sequence identity to its homologue in the second species.

65. The composition of claim 62, wherein a homologue of a first species has at least about 90% sequence identity to its homologue in the second species.

66. The composition of any one of claims 55 to 65, wherein the amino acid sequence from the first species and the amino acid sequence from the second species have a Z score of from about 2 to about 8 when aligned using distance matrix alignment.

67. The composition of claim 66, wherein the amino acid sequence from the first species and the amino acid sequence from the second species have a Z score of at least 8 when aligned using distance matrix alignment.

68. The composition of any one of claims 55 to 67, wherein the polypeptide derived from the first species and its homologue polypeptide from the second species are antibodies.

69. The composition any one of claims 55 to 67, wherein the polypeptide derived from the first species and the at least one heterologous amino acid sequence derived from the second species are derived from an antibody heavy chain or an antibody light chain.

70. The composition of claim 69, wherein the antibody heavy chain is an IgM, IgG, IgA or IgE isotype heavy chain, or the light chain is a kappa or a lambda light chain.

71. The composition of any one of claims 55-70, wherein: the first species is a mammalian species; the second species is a mammalian species; or, the firstPATENT 6363.149133PCT / 20220053-02 species is a species of the order Galliformes or the genus Phasianidae and the second species is a mammalian species.

72. The composition of any one of claims 55-70, wherein the first species is a rabbit, a murine species, a sheep, a goat, a pig, a cow a horse or a chicken; and, the second species is a human.

73. The composition of claim 72, wherein the murine specie is a rat or a mouse.

74. The composition of any one of claims 55-73, wherein at least about 80% to about 99% of the amino acid sequence of the recombinant, chimeric antigen polypeptide is amino acid sequence derived from the first species, and / or between about 1% to about 20% of the amino acid sequence of the recombinant, chimeric antigen polypeptide is amino acid sequence derived from the at least one second species.

75. The composition of any one of claims 55-74, wherein one, two three, four, five, six, seven or eight or more dominant epitopes are removed or deleted, or are modified such that they are no longer immunogenic in the first species, or are substantially less immunogenic in the first species.

76. The composition of any one of claims 55-75, wherein one or more new epitopes from the at least one heterologous amino acid sequence or amino acid residue derived from the second or additional species has been removed after one or more new epitopes was inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species.

77. The method of any one of claims 55 to 76, wherein at least two or more different heterologous amino acid sequences or amino acid residues have been inserted into, joined to, created in, or replaced for or substituted for a portion of the amino acid sequence of the polypeptide derived from the first species.PATENT 6363.149133PCT / 20220053-02 78. The composition of claim 77, wherein the at least two or more different heterologous amino acid sequences or amino acid residues are from different animal species.

79. The composition of claim 78, wherein at least one of the at least two or more different heterologous amino acid sequences or amino acid residues is derived from a human and at least one of the at least two or more different heterologous amino acid sequences or amino acid residues is derived from a non-human or an animal species.

80. The composition of any one of claims 55-79, wherein at least one of the heterologous amino acid sequences or amino acid residues comprises an artificial epitope not derived from the at least a second species.

81. The composition of any of claims 77-80, wherein at least one of the heterologous amino acid sequences or amino acid residues comprises an epitope initially derived from the at least a second species that is immunologically silent in the first species (is unable to generate an antibody response in the first species) but is modified to be an immunologically active epitope capable of generating an antibody response against it by the first species.

82. The composition any of claims 77-81, wherein at least one new epitope in the heterologous amino acid sequences or amino acid residues is modified such that antibodies generated by the first species to the modified new epitope bind less strongly or slower than a comparable unmodified new epitope.

83. The composition of any one of claims 55-82, wherein the recombinant, chimeric antigen polypeptide further comprises at least one new epitope derived from an at least second species that is not homologous to the first species, and the at least one new epitope of capable of generating antibodies against it in the first species.

84. The composition of any one of claims 51-83, wherein a portion of said plurality of polypeptides comprises an amino acid sequence from the same species as said host and said plurality of epitopes are from a different species than said host.PATENT 6363.149133PCT / 20220053-02 85. The composition of any one of claims 51-84, wherein said host produces antibodies against each of said plurality of epitopes at substantially similar titers.

86. The composition of any one of claims 51-85, wherein said portion of said plurality of polypeptides is from rabbits and said plurality of epitopes are from a species other than rabbits.

87. The composition of any one of claims 51-86, wherein said portion of said plurality of polypeptides is from the rabbit CDv6 polypeptide.

88. The composition of any one of claims 51-87, wherein said portion of said plurality of polypeptides is from the rabbit myoglobin polypeptide.

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