Response of NZB and NZB-NZW spleen cells to mitogenic agents.

The in vitro response of pooled splenic lymphocytes from NZB, B/W, and C3H mice was studied to phytohemagglutinin (PHA), allogeneic cells and calf thymus DNA. There was no response to DNA by any of the three strains. Relative to C3H, the NZB cells were hyporeactive both to PHA and to allogeneic cells. The B/W mice were hyporesponsive to PHA and in three of eight experiments showed no response at all. However, they showed a consistent and vigorous response to C3H cells. This differential and disproportionate response to mitogens has been seen previously in humans with thymic dysplasia and in thymectomized animals. These studies showing a depressed in vitro response of lymphocytes lend support to the concept that New Zealand mice may have a relatively hypofunctioning thymus.