title: The frequency of phosphorylcholine-specific B cells in conventional and germfree BALB/C mice.
abstract: The frequency of B cells specific for phosphorylcholine (PC) in spleens of nonimmune conventionally-reared and germfree adult Balb/c mice was determined by an in vitro splenic focus technique. Analysis of spleen cells from 11 conventionally reared donors revealed an average of 19.1 PC-specific clonal precursor cells/10-6 donor B cells when calculated utilizing a cloning efficiency previously determined for the in vitro splenic focus technique of 4%. This number is one-tenth the frequency determined for 2, 4-dinitrophenyl- and 2,4,6-trintrophenyl-specific B cells; however, both idiotypic and isoelectric analysis reveal that the majority of B cells specific for PC yield monoclonal antibodies which share the TEPC 15 idiotype and contain a homogeneous IgM peak with a pK of 4.60. Thus this single clone appears on the average to be represented by more than 10-3 B cells in conventionally reared nonimmune adults. A similar frequency for precursor cells of this clonotype was found in an analysis of seven  germfree adult mice so that the high frequency of B cells of this colontype appears to be independent of previous antigenic stimulation. Among the 11 conventionally reared donors analyzed, frequencies varied from 1.6 to 52/10-6 B cells--an extreme degree of variation when compared to the almost invariant frequencies observed for 2, 4-dinitrophenyl, 2, 4, 6-trinitrophenyl, and fluoroscein. This variation is interpreted as a reflection of the life cycle of a single clone with a possible role for antigen implied by smaller variations observed in grem free mice.
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D002794:Choline / Q000031:analogs & derivatives* / Q000276:immunology; D006433:Hemocyanins / Q000276:immunology; D007457:Iodine Radioisotopes; D007525:Isoelectric Focusing; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology*; D009943:Organophosphorus Compounds / Q000276:immunology*; D010954:Plasmacytoma / Q000276:immunology; D011828:Radiation Chimera; D011863:Radioimmunoassay; D013154:Spleen / Q000166:cytology
chemical_list: D007457:Iodine Radioisotopes; D009943:Organophosphorus Compounds; D006433:Hemocyanins; D002794:Choline