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.

Short lived, dividing cells mediate adoptive transfer of immunity to Trichinella spiralis in mice. II. In vivo characteristics of the cells

The in vivo characteristics of mesenteric lymph node cells (MLNC) capable of mediating the adoptive transfer of immunity to Trichinella spiralis have been examined. Mediator cells were diverted into the peritoneal cavity of infected donor mice following the induction of a peritoneal exudate and its was shown that these were nylon-wool, non-adherent (T) cells. After density gradient separation of [125I]-UdR-labelled MLNC, the fractions that were most effective in transferring immunity were those containing a small proportion of cells but the largest proportion of incorporated activity. Treatment of the donors of MLNC with the mitotic inhibitor vinblastine effectively prevented both the transfer of immunity and increased incorporation of [125I]-UdR characteristic of the mediator population. In vitro irradiation of MLNC failed to affect their ability to transfer immunity. Collectively these findings support the conclusion that mediator cells are T lymphoblasts, and suggest that mediation of immunity is effected directly by this population and not by their progeny.

Specific cross-immunity between Trichinella spiralis and Trichuris muris: immunization with heterologous infections and antigens and transfer of immunity with heterologous immune mesenteric lymph node cells

Infections with either 300 infective Trichinella spiralis larvae or 400 embryonated eggs of Trichuris muris were infective in eliciting accelerated expulsion of heterologous challenge infections given 20 days after the primary infection. Accelerated expulsion could also be achieved by the administration of soluble crude worm antigen given 12 days prior to heterologous challenge or by adoptive transfer of mesenteric lymph node cells taken from mice infected with the heterologous parasite. Each species is capable of eliciting an accelerated secondary expulsion response in hosts that have been actively or adoptively immunized against the other species and these results are taken to indicate that there is a specific cross-immunity between T. spiralis and T. muris due to shared antigens. It is postulated that these shared antigens are derived from stichocyte granules.