engleski

Increased number of intestinal villous M cells in levamisole - pretreated weaned pigs experimentally infected with F4ac+ enterotoxigenic Escherichia coli strain

Immunoprophylaxis of porcine postweaning colibacillosis (PWC) caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 fimbriae is an unsolved problem. Just as ETEC strains can exploit intestinal microfold (M) cells as the portal of entry for infection, their high transcytotic ability make them an attractive target for mucosally delivered vaccines, adjuvants and therapeutics. We have developed a model of parenteral/oral immunization of 4-weeks-old pigs with either levamisole or vaccine candidate F4ac+ non-ETEC strain for studying their effects on de novo differentiation of antigen-sampling M cells. Identification, localization and morphometric quantification of cytokeratin 18 positive M cells in the ileal mucosa of 6-weeks-old pigs revealed that they were: (1) exclusively located within villous epithelial layer, (2) significantly numerous (p < 0.01) in levamisole pretreated/challenged pigs, and (3) only slightly, but not significantly numerous in vaccinated/challenged pigs as compared to nonpretreated/challenged control pigs. A fact that levamisole may affect the frequency of M cells by increasing their numbers, makes it an interesting adjuvant to study development of an effective M cell-targeted vaccine against porcine PWC.

Levamisole; M cells; E. coli vaccine; Weaned pigs

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