＜Poster＞Mouse peptidoglycan recognition protein（ PGRP）-S : the role in bacterial infection

Peptidoglycan recognition proteins （PGRPs） are pattern recognition receptors which are conserved from insects to humans. PGRPs can recognize bacteria and their cell wall components, peptidoglycans. Human PGRPs have bactericidal activities that can be accomplished by their amidase activities. Insect PGRPs consist of 16 subtypes and some have eff ector functions as the activation of Toll pathway （PGRP-SA）, the activation of Imd pathway （PGRPLC） and induction of autophagosome formation （PGRP-LE）, thus contribute to the elimination of bacteria. However, the role of mammalian PGRPs in bacterial infection remains unclear. In this study, we report the function of mouse PGRP-S, the homologue of PGRP-SA, in bacterial infection. The recombinant protein was produced in Escherichia coli overexpression system and used for specifi c antibody production. We investigated the role of PGRP-S in infection with Listeria monocytogenes, a facultative Gram-positive bacterium that can grow intracellularly. The administration of recombinant PGRP-S before L. monocytogenes infection decreased the number of bacteria in the organs of infected mice. When endogenous PGRP-S was neutralized by antibodies specifi c to PGRP-S, the bacterial number increased. The levels of proinfl ammatory cytokines that are essential in the protection against L. monocytogenes infection were lower when the specific antibody was administered prior to infection. Together with these, it is suggested that PGRP-S plays a role in the protection against L. monocytogenes infection