The involvement of the macrophage mannose receptor in the innate immune response to infection with parasite Trichinella spiralis.

The macrophage mannose receptor (MR) is a pattern recognition receptor of the innate immune system that binds to microbial structures bearing mannose, fucose and N-acetylglucosamine on their surface. The MR can mediate endocytosis and phagocytosis, as well as activation of macrophages and antigen presentation. Since Trichinella spiralis antigens are rich in oligomannose residues, we investigated whether a mannose-recognizing receptor, such as the MR, participated in the host-parasite interaction. The results show that the MR (either on the surface of macrophages or in the purified form) recognizes and binds components of T. spiralis muscle larvae. The presence of parasites provoked activation of peritoneal macrophages, which was indicated by down-regulation of MR expression, and the stimulation of NO secretion. In vitro stimulation of macrophages with T. spiralis components resulted in increased NO and IL-6 production. However, while the MR was partially involved in stimulation of NO production, it did not mediate IL-6 secretion.