Antibodies from the Lyb-5- B cell subset predominate in the secondary IgG response to phosphocholine.
The X-linked CBA/N immune defect was used to investigate the role of the Lyb-5- B cell subset in phosphocholine- (PC) specific memory responses. Immune-defective mice, which express only the Lyb-5- B cell subset, are unable to mount a primary or secondary T15+, IgM response to PC but can produce a substantial secondary IgG response. The majority of these IgG anti-PC antibodies are T15- and can be inhibited by phenylphosphocholine, but not PC. Normal mice, which possess Lyb-5+ and Lyb-5- B cells, produce both IgM and IgG anti-PC antibodies; however, there is a striking difference in the idiotype and fine specificity of antibodies expressed by these two classes. The IgM anti-PC antibodies are T15+ and PC-inhibitable, whereas the IgG antibodies are identical to those observed in the immune-defective mice, i.e., T15- and PC-noninhibitable. This unexpected difference in both idiotype and fine specificity between IgM and IgG anti-PC antibodies results from activation of different B cell subsets. Lyb-5+ B cells produce T15+, PC-inhibitable IgM antibodies, whereas T15-, PC-noninhibitable IgG antibodies are produced by Lyb-5- B cells. These data indicate that a majority of the thymus-dependent, anti-PC IgG memory responses arises from Lyb-5- B cells.
D000818:Animals; D000917:Antibody Formation; D000918:Antibody Specificity; D000950:Antigens, Ly; D001402:B-Lymphocytes / Q000276:immunology*; D002794:Choline / Q000031:analogs & derivatives*; D007116:Immunization, Passive; D007074:Immunoglobulin G / Q000096:biosynthesis; D007130:Immunoglobulin Idiotypes; D007075:Immunoglobulin M / Q000096:biosynthesis; D007156:Immunologic Memory; D051379:Mice; D008815:Mice, Inbred Strains / Q000276:immunology; D010767:Phosphorylcholine / Q000276:immunology*
D000950:Antigens, Ly; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes; D007075:Immunoglobulin M; D010767:Phosphorylcholine; D002794:Choline