In vitro modelling of rat mucosal mast cell function in Trichinella spiralis infection

Intestinal infection with the parasitic nematode, Trichinella spiralis, provides a robust context for the study of mucosal mast cell function. In rats, mucosal mast cells are exposed to parasites during the earliest stage of infection, affording an opportunity for mast cells to contribute to an innate response to infection. During secondary infection, degranulation of rat mucosal mast cells coincides with expulsion of challenge larvae from the intestine. The goal of this study was to evaluate the rat bone marrow-derived mast cells (BMMC) and the rat basophilic leukaemia cell line (RBL-2H3) as models for mucosal mast cells, using parasite glycoproteins and antibody reagents that have been tested extensively in rats in vivo. We found that BMMC displayed a more robust mucosal phenotype. Although T. spiralis glycoproteins bound to mast cell surfaces in the absence of antibodies, they did not stimulate degranulation, nor did they inhibit degranulation triggered by immune complexes. Parasite glycoproteins complexed with specific monoclonal IgGs provoked release of rat mast cell protease II (RMCPII) and β-hexosaminidase from both cell types in a manner that replicated results observed previously in passively immunized rats. Our results document that RBL-2H3 cells and BMMC model rat mucosal mast cells in the contexts of innate and adaptive responses to T. spiralis.