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Title: EIMERIA BOVIS INFECTION IN CALVES: IMMUNE RESPONSES TO A PRIMARY INFECTION

Author
item ALMERIA, S. - 1265-20-00
item GOMEZ-MUNOZ, M. - 1265-20-00
item PASQUALI, P. - 1265-20-00
item STROMBERG, B - U.MN, ST. PAUL, MN
item CANALS, A. - 1265-20-00
item GASBARRE, LOUIS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/27/1999
Publication Date: N/A
Citation: Almeria, S., Gomez-Munoz, M.T., Pasquali, P., Stromberg, B., Canals, A., Gasbarre, L.C. 1999. Eimeria bovis infection in calves: immune responses to a primary infection. Meeting Abstract.

Interpretive Summary:

Technical Abstract: The purpose of this experiment was to characterize the effector populations and mechanisms that operate in the gut-associated lymphoid tissues during the course of a primary infection with Eimeria bovis. Twelve calves were infected orally with 2 x 10-5 oocysts of E. bovis and six calves served as uninfected controls. Surface marker phenotypes of intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL) of ileum and colon, mesenteric lymph nodes (MLN) and ileum-cecal lymph nodes (ICLN) were characterized from infected and control calves at 2 or 3 weeks after infection. As early as 14 days after infection (DAI) a few animals began shedding oocysts, but the majority of infected animals began shedding oocysts after the 18th day. The number of oocysts varied greatly in the infected animals from 0 to 77,700, while no oocysts were observed in the control calves. At 3 weeks after infection significant increases in size and weight as well as important phenotypic changes were observed in both regional lymph nodes (MLN and ICLN). The increases in size were related to significant increases in the numbers of macrophages and gamma-delta TCR positive cells in both MLN and ICLN. Although not significant, populations of T cells, mainly CD2 and CD4 decreased in regional lymph nodes at that time. However, numbers of activated T-cells, CD4+-IL2R+ cells, were also increased in MLN. At the mucosal level, 3 weeks post infection, the primary lymphocyte changes were observed in colonic IEL. Increased numbers of colonic IE macrophages and a significant increase of CD4+ at 3 weeks after infection were the primary changes observed.