1. CD5+ B cells are preferentially expanded in rabbit appendix: the role of CD5 in B cell development and selection.
- Author
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Pospisil R, Alexander CB, Obiakor H, Sinha RK, and Mage RG
- Subjects
- Amino Acid Sequence, Animals, Appendix cytology, B-Lymphocytes cytology, Base Sequence, Bone Marrow immunology, Gene Rearrangement, B-Lymphocyte, Heavy Chain, Genes, Immunoglobulin, Immunoglobulin Heavy Chains genetics, Immunoglobulin M, Immunoglobulin Variable Region genetics, L-Selectin, Molecular Sequence Data, Rabbits growth & development, Spleen cytology, Spleen immunology, Appendix immunology, B-Lymphocytes immunology, CD5 Antigens physiology, Rabbits immunology
- Abstract
Although only a small proportion of mouse and human B cells are CD5(+), most adult rabbit B cells express CD5. However, CD5 was not detectable on the majority of B cells in neonatal appendix 1 and 3days after birth. Cell trafficking studies demonstrated that CD5(+) and CD5(-) CD62L(+) B cells from bone marrow migrated into appendix. There, CD5(+) B cells were preferentially expanded and predominated by approximately 2weeks of age. In mutant ali/ali rabbits, VHa2(+) B cells develop through gene conversion-like alteration of rearranged VH genes upstream of deleted VH1a2. Correlated appearance of individual CD5(+) germinal centers and VHa2(+) B-cells in mutant appendix suggests that CD5 binding positively selects cells with a2(+) framework regions that bind CD5. Following negative and positive selection, cells with diversified rearranged heavy- and light-chain sequences exit appendix, migrate to peripheral tissues and constitute the preimmune repertoire of CD5(+) B cells that encounter foreign antigens.
- Published
- 2006
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