Apotosis and proinflammatory cytoquines induced in Peyer´s patches by attenuated strains of Salmonella enteritidis.

CERQUETTI MC; VACCARO MI; GOREN N; ROPOLO A; GRASSO D; GHERARDI MM; GIACOMODONATO MN

Florida, Orlando, USA.

Congreso; 101nd General Meeting of the American Society for Microbiology; 2001

American Society for Microbiology

Temperature-sensitive (ts) mutants of S. enteritidis have been used in different animals models to induce protection. C/2/2 and E/1/3 ts mutants of S. enteritidis are highly innocuous when administrated oral to mice. Both mutants are able to invade murine Peyer´s patches (PP), but only E/1/3 satin is protective. In this study we investigated the capacity of protective a non protective mutants of S. enteritidis to induce apoptosis and the release of proinflammatory cytoquines in murine PP. Balb/c mice were inoculated orally with 109 CFU/animal of each mutant; 6 hs later mice were sacrificed and the intestine were removed aseptically. NOS activity was determinate by measuring the production of 14C citrulline from 14C arginine. Apoptosis in PP was analyzed using the TUNEL assay. Interleukin (IL) 12, IL18 and INF-gamma were determinate by ELISA. Hyperplastic PP were found in mice inoculated with either strain of S. enteritidis. Apoptosis was observed in PP of inoculated animals as well as in control mice although there were differences in localization. In control mice, apoptotic cells appeared evenly distributed whereas mice inoculated with Salmonella showed apoptosis in the germinal centers. Affected foci in PP of animals inoculated with the protective strain E/1/3 were larger than those observed in mice receiving the non protective mutant C/2/2. The NOS activity measured in animals inoculated with the protective E/1/3 mutant has higher (p<0.05) to that found in mice given the non protective one (706 ± 25 vs 318 ± 114 pmol/g). The non protective mutant C/2/2 seems to induce a lower or a delayed inflammatory response since all cytoquines measured 6 hs after inoculation were diminished. Our results suggest that early induction of mucosal inflammatory response may be a main feature of the protective phenotypes of ts mutants of S. enteritidis.