Age-associated decline of immune functions in mice congenic at the H-2 locus

Abstract

Two different strains of congenic mice were used to study the influence of the H-2 complex on the age-associated decline of different parameters of the immune function. Aged C57BL/10 and C57BL/10.BR mice demonstrated significantly reduced plaque forming cell (PFC) responses to both T-dependent and-independent antigens. However, the response to sheep red blood cell (SRBC) was more significantly affected suggesting that T-cells were impaired to a greater extent than B-cells. Congenic differences were only observed in young mice in the SRBC-specific response, while both young and old congenics demonstrated significantly different responses to TNP-LPS. Thymic weight, mitogenic responses and interleukin-2 (IL-2) production also diminished with aging. Natural killer (NK) activity appeared to be more affected with aging than any of the other immune responses as it almost disappeared in old mice. NK activity did not differ between congenic mice of the same age. In an attempt to restore immune functions in aged mice, animals were treated with the immunostimulant poly (I•C). Of all the immune parameters tested only NK activity and antibody responses were affected. Our data suggest that there is an H-2 dependence in age-specific change of immune functions. It appears that H-2 controlled age-associated changes affect the functional status of the cells more than frequency.