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Background Immunoglobulin heavy chain variable region(IgHV)is a well-characterized tumor antigen for B-cellmalignancies.It can function as a target for T cell-mediated immune response.Clinical trials of IgHV protein vaccinesagainst lymphoma have demonstrated induction of tumor-specific cytotoxic T lymphocyte(CTL)responses.However,complementary determining regions-based individual vaccines have disadvantages for wide clinical application.Althougha recent study demonstrated that immunogenic peptides are derived from framework regions(FR)shared amongpatients with B-cell lymphoma,how to choose the appropriate peptides for each patient is still unsolved.The aim of thisstudy was to investigate whether immunoglobulin heavy chain FR-derived peptides shared in each IgHV family arepotential CTL epitopes presented by B-cell acute lymphoblastic leukemia(B-ALL).Such CTL epitopes might be beneficialto shifting vaccination strategies against B-ALL from individual specificity to family specificity.Methods Seven IgHV gene families were amplified respectively by PCR and sequenced directly from 71 childhoodB-ALL cases.Bioinformatics was applied in analyzing characteristics of sequences available and predictingHLA-A~*0201-restricted CTL epitopes for each IgHV family.An antigen-specific T cell expansion system was used togenerate peptide-specific CTLs.The cytotoxicity of CTLs against B-ALL cells was assessed in the lactate dehydrogenaserelease assay.Results Complete IgHV rearrangements were identified in all of the 71 B-ALL cases.All of 40 sequences availableshowed ≥98% homology with the nearest germline IgHV genes,indicating IgHV genes in B-ALL of germline nature.Twelve nonapeptides of high HLA-A~*0201-binding scores were obtained from 26 productive IgHV protein sequences.Ten(83%)of the peptides were located in FR1 and FR3 shared among the corresponding IgHV family.CTLs specific for thepeptide QLVQSGAEV located in FR1(3-11)shared among the IgHV1 family could be successfully generated fromperipheral blood mononuclear cells of two HLA-A~*0201+healthy donors in vitro and were capable of killing HLA-matchedB-ALL cell clones belonging to the IgHV1 family.Conclusion Anti-B-ALL CTLs against immunoglobulin heavy chain FR-derived peptides have family-specificcytotoxicity.
Background Immunoglobulin heavy chain variable region (IgHV) is a well-characterized tumor antigen for B cellllignancies. It can function as a target for T cell-mediated immune response. Clinical trials of IgHV protein vaccines against lymphoma have demonstrated induction of tumor-specific cytotoxicity T lymphocyte (CTL) responses. Award of determining-based individual vaccines have disadvantages for wide clinical application. Althougha recent study demonstrated that immunogenic peptides are derived from framework regions (FR) shared amongpatients with B-cell lymphoma, how to choose the appropriate peptides for each patient is still unsolved. The aim of this study was to investigate whether immunoglobulin heavy chain FR-derived peptides shared in each IgHV family are potential CTL epitopes presented by B-cell acute lymphoblastic leukemia (B-ALL) .Such CTL epitopes might be beneficial to shifting vaccination strategies against B-ALL from individual specificity to family specificity. Met hods Seven IgHV gene families were amplified respectively by PCR and sequenced directly from 71 childhood B-ALL cases. Bioinformatics was applied in analyzing characteristics of sequences available and predicting HLA-A * 0201-restricted CTL epitopes for each IgHV family. Antigen-specific T cell expansion system was used togenerate peptide-specific CTLs. The cytotoxicity of CTLs against B-ALL cells was assessed in the lactate dehydrogenase release assay. Results Complete IgHV rearrangements were identified in all of the 71 B-ALL cases. All of 40 sequences availableshowed ≥ 98% homology with the nearest germline IgHV genes, indicating IgHV genes in B-ALL of germline nature. Welco nonapeptides of high HLA-A ~ * 0201-binding scores were obtained from 26 productive IgHV protein sequences. Ten peptides were located in FR1 and FR3 shared among the corresponding IgHV family. CTLs specific for the peptide QLVQSGAEV located in FR1 (3-11) shared among the IgHV1 family could be successfully generatedHLA-matched B-ALL cell clones belonging to the IgHV1 family. Conflicting Anti-B-ALL CTLs against immunoglobulin heavy chain FR-derived peptides have family-specificcytotoxicity.