Short lived, dividing cells mediate adoptive transfer of immunity to Trichinella spiralis in mice. I. Availability of cells in primary and secondary infections in relation to cellular changes in the mesenteric lymph node.

After a primary infection with the parasitic nematode Trichinella spiralis NIH mice showed a short lived increase in cellularity of the mesenteric lymph node (MLN), which began between days 2 and 4 peaked at day 8 and had declined by day 21. The majority of cells contributing to this increase were Ig-ve and presumed to be T cells. Coincident with the increase in cell number there was an increase in lymphoblast activity, again largely in the T-cell fraction. MLN cells taken at intervals from mice during a primary infection successfully transferred immunity, i.e. accelerated worm expulsion in recipients, on days 4 and 8, but not on day 21. It was shown that the effective cells in transferring immunity were present in the T-enriched fraction. When mice were present in the T-enriched fraction 21 days after a primary infection the same sequence of changes was apparent in the MLN, but the time course was accelerated, i.e. peak cellularity and lymphoblast activity occurred on day 4 post challenge. Cells capable of transferring immunity were present in the MLN on days 2 and 4 post challenge but not thereafter. As in the primary infection the effective cells, and those responsible for the cellular changes in the MLN, were T cells.