Induction of T lymphocyte subsets and levels of interleukin-2 and interleukin-3 after infection with Trichinella spiralis are similar in mice of high- and low-responder phenotypes.

Various aspects of T lymphocyte responses in mice with high- and low-responder phenotypes to infection with the nematode Trichinella spiralis were compared. Mesenteric lymph node cells (MLNC) from infected NIH strain mice (high-responder) showed a much higher level of proliferation in response to parasite antigen than MLNC from infected C57.B10 mice (low-responder). Levels of CD4+ and CD8+ T lymphocytes in the MLN remained relatively constant in both strains, ruling out the possibility that the more rapid worm expulsion in NIH mice (day 6 post-infection, as compared to day 12-15 in B10 mice) was due to quantitative differences in levels of CD4+ T helper cells. To examine any variation in the recruitment of Th1 v Th2 cell subsets, the production of the cytokines interleukins-2, -3, and -4 (IL-2, -3, and -4) by MLNC in response to parasite antigen was measured throughout the course of infection. Amounts of IL-2 and IL-3 were broadly similar in both strains, while almost background levels of IL-4 were detected. However, NIH strain mice produced IL-2 and IL-3 more rapidly than B10 mice. These data support the conclusion from other authors that the response to T. spiralis is not dependent on the absolute levels of cytokines produced, but rather on timing of production and rapidity of recruitment of effector cells at the level of bone marrow precursors.