B-cell superantigens may play a role in B-cell development and selection in the young rabbit appendix.
In order to develop protective antibodies against a wide range of potentially infectious pathogens, the young rabbit must diversify a limited initial repertoire by somatic mechanisms (the high copy number primary repertoire). The majority of rabbit B cells produce heavy chain variable regions by rearranging the VHa allotype-encoding VH1 gene. Thus in normal rabbits the majority of serum immunoglobulins bear VHa allotype (due to VH1 FR1 and FR3 sequences). The young rabbit appendix is a site of diversification of rearranged VH genes by gene-conversion-like and somatic hypermutation mechanisms. The newly generated B cells probably undergo selection processes that involve foreign and self-antigens and superantigens. We find preferential expansion and survival of B cells in normal and VH-mutant ali/ali rabbits based on their heavy chain FR1 and FR3 sequences (VHa allotype). This selection may involve "superantigen"-like interactions with endogenous as well as exogenous ligands.
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Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-1892, USA.
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D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D001065:Appendix / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002469:Cell Separation; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology; D019938:Cyclin D1 / Q000502:physiology; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D009154:Mutation / Q000276:immunology; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology; D011817:Rabbits; D018089:Superantigens / Q000502:physiology*; D014443:Tyrosine / Q000378:metabolism; D051020:bcl-X Protein
D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D019253:Proto-Oncogene Proteins c-bcl-2; D018089:Superantigens; D051020:bcl-X Protein; D019938:Cyclin D1; D014443:Tyrosine