engleski

Modulating of porcine intestinal immune functions by F4 antigen of Escherichia coli or immune response modifiers

We have stimulated porcine intestinal immunity in 4-week-old pigs perorally inoculated with either F4ac^+ (2407) or F4ac^- (1467) non-enterotoxigenic E. coli (non-ETEC) strains. Also, we have evaluated in vitro and in vivo adjuvanticity of the immune response modifiers (IRMS) such as peptidoglycan monomer (PGM), Baypamun (BPM) and Gerbu (GMDP) adjuvant in a model of post-weaning colibacillosis. Non-ETEC strain 2407 activated lymphocytes from ileal Peyer's patches (IPP) and mesenteric lymph node (MLN) to respond better to control mitogens (PHA and PWM; P < 0.01 or < 0.05, respectively), BPM or PGM (P < 0.05) than the cells from non-inoculated pigs. Non-adherent strain 1467 did not affect the in vitro responsiveness of the cells tested. The numbers of CD4a^+ and CD8a^+ cells were much higher (P < 0.05) in IPP and jejunal lamina propria, respectively. In 2407 + GMDP- or 2407-treated pigs we have observed that CD3a^+ T-cells were expressed on jejunal/ileal intraepithelial lymphocytes, numerous cells in the extrafollicular areas of MLN and dome region of IPP. The B-cells expressing CD21 antigen were demonstrable in the interfollicular areas of MLN and the germinal centers of IPP in 2407-treated pigs. A strong reaction to sIgA was exhibited by plasma cells in the lumen of the crypts and by those residing the lamina propria of jejunum/ileum. It was concluded that immunization of weaned pigs with vaccine candidate non-ETEC strain 2407 may induce mucosal (intestinal) immune response, which could be additionally enhanced by IRMs tested.

Intestinal immunity; vaccination; immune response modifiers; E. coli; pigs

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