Lymphocyte proliferation and cytokine production in mice infected with different geographical isolates of Trichinella spiralis.

Antigen-specific proliferative responses and cytokine production were measured in lymphocytes taken from inbred NIH mice infected with different isolates of Trichinella spiralis. Stimulation with muscle larval homogenate antigen produced high proliferative responses, cells responding more strongly to antigen from one isolate (London-L) than to antigens of the other two isolates (Spanish-S and Polish-P). Antigen from the P-isolate elicited relatively poor responses. There was considerable, although variable, cross reactivity between isolate antigens and this was reflected in proliferation to heterologous stimulation. When pulsed with the mitogen Concanavalin A (Con-A) mesenteric lymph node cells (MLNC) produced IFN-gamma on day four post infection but not on day eight. In contrast, production of IL-4 and IL-5 was greatest on day eight. Differences were seen in levels of cytokine production between cells taken from mice infected with different isolates. These data show a sequential activation of Th1 and Th2 cells during infection with T. spiralis isolates, and suggest that the level of activation of each Th subset is influenced by the antigenic characteristics of each isolate.