1981 Volume 18 Issue 6 Pages 476-483
It is generally accepted that responses of peripheral lymphocytes from the aged to phytohaemagglutinin (PHA) and concanavalin A (Con-A), which are well known stimulators of T cells, are lower than those from the young. However, the functional capacity of Bcells from the aged has not'as yet been fully i vestigated. In this report, peripheral lymphocytes 'from the aged over 70 years of age and the young from 22 to 36 years were examined for their responsiveness to PHA and Con-A'in vitro, and the imparied T cell function of the aged was reconfirmed. Furthermore, B cell responses to pokeweed mitogen (PWM) and Staphylococcus aureus Cowan I strain bacteria (SpA) were also compared in vitro between the two age-groups.
Peripheral lymphocytes were cultured for a period of 24hrs to 8 days in the presence of PHA, Con-A or PWM to measure 3H-uridine and 3H-thymidine uptake by the cells. Peripheral lymphocytes from the aged responded significantly less to PHA and Con-A than those from the young. No significant difference was detected in responses to PWM between the two age-groups.
Peripheral lymphocytes were separated into ′T cell-enriched and B cell-enriched populations by rosetring with neuraminidasetreated sheep red blood cells. Mitomycin C (MMC)-treated T cells+B cells were cultured in the presence of PWM for 4 days to measure 3H-thymidine uptake by B cells. 3H-thymidine uptake by MMC-treated T′ cells from the young+B cells from the aged was significantly lower than that by MMC-treated T cells from the young+B cells'from the same group. 3H-thymidine uptake by MMC-treated T cells from the aged+B cells from the aged was also significantly lower than that by MMC-treated T cells from the aged+B cells from the young. Effect of SpA, which is a known polyclonal activator of human B cells, was similarly studied, revealing that 3H-thymidine uptake by the lymphocytes from the aged was significantly lower than that from the young.
These results indicate that the decreased immune function in the aged reflects the impaired functions of not only T cells but also B cells and/or monocytes.
