The temporal relationship among anti-parasite immune elements expressed during the early phase of infection of the rat with Trichinella spiralis

Immunological parameters were measured during the first 20 days of infectio n with Trichinella spiralis in the rat. Expulsion of adult worms was comple te by day 15 postinfection. Eosinophil and neutrophil numbers rose in the b lood of infected rats above preinfection levels on days 3 and 6, respective ly, and remained high to day 20 postinfection. Release of cytokines by Tric hinella-antigen-stimulated mesenteric lymph node cells was measured, and a significant elevation in interferon (IFN)-gamma release was detected during the early stage of infection. Although initiated later, interleukin (IL)-1 0 release showed a pattern similar to IFN-gamma. Biphasic release of IL-5 w as seen with significant elevation above the preinfection level on day 3 an d after day 6 postinfection to the end of the study. IL-4 and IL-2 showed b iphasic secretion as well, with the level of IL-4 high in the early and mid dle part of infection, while the level of IL-2 was detectable only at days 2, 3 and 6 postinfection. Serum anti-parasite IgE rose above preinfection l evels after day 6 postinfection. Anti-parasite Ig-positive mesenteric lymph node (MLN) cells were evident by day 3 postinfection for IgM, and day 9 po stinfection for ISA. and total IgG. The number of Ig-positive MLN cells for all antibody classes returned to preinfection levels by day 20 postinfecti on. Evaluation of the temporal interactions of the key anti-parasite immune components with which the host engages Trichinella shows a complex interpl ay between Th1 and Th2 helper subsets.