Age-dependent changes of the levels of suppressor and helper T cells in New Zealand black mice.

Peanut agglutinin-positive (PNA+) T cells in concanavalin A (Con A) activated spleen cells were found to markedly decrease with age in New Zealand black (NZB) mice but not in non-autoimmune strains, using a fluorescence activated cell sorter (FACS II). On the other hand Limulus polyphemus agglutinin positive (LPA+) T cells in Lens culinaris agglutinin (LcA) activated spleen cells were found to gradually decrease both in NZB and non-autoimmune strains. Since PNA has previously been shown to selectively label Con A-induced suppressor T cells, these results support the previous observation by other investigators that suppressor T cell function declines with age in NZB mice. It was also demonstrated that the level of one of natural thymocytotoxic autoantibodies (NTA-2) developed in NZB mouse serum, which had been shown to have a similar carbohydrate binding specificity to PNA and to exert a cytotoxic effect specifically against suppressor T cells, was elevated early in the life of NZB mice. These results suggest a possible role of NTA-2 in the decline of PNA+-T cells in vivo.