Natural lymphocyte activation in postnatal development of germ-free and conventional mice.
The degree of activation of B and T cells in the developing spleen during postnatal life was studied in germ-free (GF) and specific-pathogen-free (SPF) BALB/c mice of the same breeding stock. We found that the progeny of GF mothers up to 3 weeks of age contain higher numbers of activated splenic cells than baby SPF mice, thus suggesting qualitative differences in maternally-derived antibodies. This "advantage" of GF mice is also indicated by an anticipated maturation of the splenic lymphoid compartment and is reflected in higher frequencies of B and T lymphocytes in adult life. In both kinds of mice, the frequency of activated cells is very high at birth and then declines, reaching minimal values by 4 weeks of age. Later, activated B cells increase sharply in SPF mice, suggesting polyclonal activation mediated by bacterial products. Results are discussed on the basis of the mutual influences between B and T cells in the establishment of a functional network.
Forni
L
L
Basel Institute for Immunology, Switzerland.
Heusser
C
C
Coutinho
A
A
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D005260:Female; D005856:Germ-Free Life; D007107:Immune System / Q000254:growth & development*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000254:growth & development / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology