title: Characterization of T and B antigen-binding cells for beta-galactosidase. III. Independence of antigen-binding cells in normal animals from antigenic stimulation.
abstract: Antigen-binding cells to beta-galactosidase were enumerated in thymus and spleen of mice of different ages and found to remain at a constant frequency throughout life. Thymic beta-galactosidase-binding cells (ZBCs),6 representing T-binding cells, showed no appreciable fluctuation, whereas splenic ZBCs, a mixture of T- and B-binding cells, were slightly depressed at birth but found at normal frequencies by 1 week of age. In addition, germfree mice, both within the 1st week after birth and after maturity, had nearly as many binding cells as did conventionally reared age-matched mice. These results considered together suggest that the ability of cells of both T and B origin to  recognize antigen, as revealed by their ability to bind beta-galactosidase, arise independently of specific or nonspecific antigenic stimulation, as part of the normal ontogenic sequence of steps of differentiation. This is consistent with the theory of clonal precommitment of T and B cells.
mesh_terms: D000375:Aging; D000818:Animals; D000937:Antigen-Antibody Reactions; D001402:B-Lymphocytes / Q000276:immunology*; D001666:Binding Sites, Antibody; D005696:Galactosidases / Q000276:immunology*; D005856:Germ-Free Life; D051379:Mice; D008808:Mice, Inbred CBA; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology
chemical_list: D005696:Galactosidases