Ageing and immunity in outbred NMRI mice: lack of correlation between age-related decline of the response to T cell mitogens, the antibody response to a T-dependent antigen and lifespan in outbred NMRI mice.

Responses to different mitogens and the primary in vitro antibody response to a T-dependent antigen (SRBC) were tested in individual mice of various ages from an outbred strain (NMRI). Comparing mean values, an age-related decrease was found only for the responses to Con A and PHA but not for LPS nor for the primary in vitro antibody response to SRBC. The magnitude of the responses obtained in individual mice of the same age varied greatly. Some of the young as well as aged animals could respond very well to antigen, mitogen or both and there was a complete lack of correlation between the magnitude of individual responses to mitogen and the number of PFC produced in the in vitro antibody response to SRBC. Additionally, we investigated whether the magnitude of the immune responses measured in individual mice had any influence on their lifespan. The mitogen response and the in vitro PFC production of spleen cells from individual semi-splenectomized mice were therefore compared with their lifespan. The lifespan did not appear to be influenced by any of the immune responses measured.