engleski

Intestinal Immune Response of Weaned Pigs Experimentally Vaccinated with F4ac+ Nonenterotoxigenic Strains of Escherichia coli

The potential effect of two adjuvants: copolymer of polyoxyethylene-polyoxypropylene (POE-POP) and N-acetylglucosaminyl-( , 1-4)-N-acetyl-muraminyl-L-alanyl-D-isoglutamine (GMDP) on mucosal humoral and cell-mediated immune responses was tested in weaned pigs immunized with F4ac+ non-enterotoxigenic Escherichia coli (non-ETEC) strain 2407 and challenged with F4+ ETEC strain 11-800/1/94. The presence of anti-F4ac secretory IgA (sIgA) antibody in small intestinal washes was detected by use of an indirect ELISA and the tissue-specific distribution patterns of the CD3a+ and CD21+ T and B cells, respectively, within the gut mucosa were evaluated by immunohistochemical in situ staining. The results have shown that approximately 75% of 2407+POE-POP-treated pigs, and 50% to 60% of pigs that were immunized with either 2407+GMDP or 2407 strain alone, respectively, were positive for anti-F4ac sIgA antibodies. The T cell antigen CD3a was expressed predominantly on lymphocytes in the ileal epithelium, dome region of ileal Peyer’ s patches (IPP) and extrafollicular areas of mesenteric lymph node (MLN) in 2407+GMDP or 2407-treated pigs. The B cells expressing CD21 surface molecule were present in the interfollicular areas of MLN and the germinal centers of IPP in 2407-treated pigs. A strong reaction to sIgA was determined on plasma cells in the lumen of the crypts and on the cells residing the lamina propria (LP) of jejunum and ileum from pigs immunized with 2407 strain. Obtained results implicate that peroral immunization of weaned pigs with F4ac+ non-ETEC strain may induce priming of intestinal immune cells, which can be additionally enhanced by adjuvants tested.

weaned pigs; colibacillosis; non-ETEC vaccine; adjuvants

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