engleski

Histomorphometric evaluation of intestinale cellular immune responses in pigs immunized with live oral F4ac+ non-enterotoxigenic vaccine E. coli against postweaning colibacillosis

The aim of this study was to test the effectiveness of a live attenuated mucosal vaccine against porcine postweaning colibacillosis by analyzing quantitative differences in the small intestinal leukocyte subsets of immunized vs control nonimmunized pigs. Four week old pigs were intragastrically vaccinated with a vaccine candidate F4ac+ nonenterotoxigenic E. coli strain 2407 at day 0 (with or without levamisole given as an adjuvant), challenged with a virulent enterotoxigenic strain 11-800/1/94 7 days later, euthanatized at day 13 and sampled for immunohistology. Nonvaccinated pigs received saline at day 0 and were processed as the principals. Within jejunal/ileal lamina propria and ileal Peyer’s patches immunophenotypes of lymphoid cell subsets were demonstrated by immunohistochemical avidin-biotin complex method and corresponding morphometric data were analyzed using software program Lucia G for digital image analyses. The monoclonal antibodies reactive with surface molecules on porcine immune cells such as CD3, CD45RA, CD45RC, CD21 and SWC3 enabled clear insight into distribution and proportion of T/B lymphocytes and macrophages within the gut-associated lymphoid tissues compartments examined. Vaccinated pigs had significantly increased numbers (p<0.05) of all immune cells tested as compared to those recorded in the nonvaccinated pigs. Based on distribution and morphometric analyses of porcine intestinal immune cells stimulated by an experimental mucosal vaccine, it is possible to differentiate the responses of immunized pigs from those found in the respective mucosal sites within the gut-associated lymphoid tissues of nonimmunized pigs.

immune cells; intestine; pig; F4ac+ nonenterotoxigenic vaccine; colibacillosis

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