title: Functional heterogeneity of memory B lymphocytes: in vivo analysis of TD-primed B cells responsive to secondary stimulation with TD and TI antigens.
abstract: The functional heterogeneity of memory B cells induced by a single determinant, consisting of a decapeptide representing amino acid residues 103-112 of tobacco mosaic virus protein (TMVP), was analyzed. Decapeptide specific antibodies were elicited in mice adoptively transferred with TMVP-immune spleen cells when challenged with TMVP, decapeptide conjugated to succinylated human gamma-globulin (SHGG), or decapeptide conjugated to Brucella abortus (BA). Whereas secondary stimulation by either TMVP or decapeptide-SHGG was dependent on appropriately primed T cells, stimulation by decapeptide-BA was independent of conventional T cell help. Furthermore, memory B cells responsive to TMVP (TD), decapeptide-SHGG (TD), or decapeptide-BA (TI. 1 prototype) were shown to consist of overlapping populations because adoptive recipients of TMVP-primed cells challenged simultaneously with TD and TI decapeptide antigens did not result in a higher antibody response than that elicited by one of the TD antigens injected alone. However, decapeptide-BA consistently induced a smaller antidecapeptide response than either TMVP or decapeptide-SHGG. This suggested that only a fraction of the memory B cell population which was activated by the original priming antigen (thymus-dependent) was also responsive to secondary in vivo stimulation by the priming hapten conjugated to Brucella abortus. Detailed analyses of the antibodies induced in the recipients of TMVP-immune spleen cells after secondary challenge with either TMVP, decapeptide-SHGG, or decapeptide-BA failed to distinguish between the responsive memory B cells; the antidecapeptide antibodies induced by all three immunogens shared the same fine specificities and immunoglobulin isotype composition. These data are viewed as further evidence that subsets of TD-primed B cells, which may display differential sensitivity to cross-stimulation with TD and TI forms of the antigen, represent distinct stages of memory B cell maturation within a common B cell lineage. In support of this conclusion, we establish a developmental relationship between TI and/or TD responsive decapeptide memory B cell in the following communication.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000918:Antibody Specificity; D000955:Antigens, T-Independent / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002003:Brucella abortus; D003429:Cross Reactions; D000939:Epitopes / Q000276:immunology*; D005362:Ficoll; D051379:Mice; D008815:Mice, Inbred Strains; D013601:T-Lymphocytes / Q000276:immunology; D014027:Tobacco Mosaic Virus / Q000276:immunology; D014764:Viral Proteins / Q000276:immunology*; D005719:gamma-Globulins / Q000276:immunology
chemical_list: D000955:Antigens, T-Independent; D000939:Epitopes; D014764:Viral Proteins; D005719:gamma-Globulins; C026594:succinyl-human gamma-globulin; D005362:Ficoll