Glycosylphosphatidylinositol-anchored mucin-like glycoproteins isolated from Trypanosoma cruzi trypomastigotes induce in vivo leukocyte recruitment dependent on MCP-1 production by IFN-γ-primed-macrophages

Glycosylphosphatidylinositol-anchoredmucin-like glycoproteins from Trypanosoma cruzi trypomastigotes (tGPI-mucins) activate macrophages in vitro to produce proinflammatory cytokines, chemokines, and nitric oxide. These effects of tGPI-mucins may be important in the ensuing immune response to T. cruzi. Here, we have sought evidence for a role of tGPI-mucins in mediating leukocyte recruitment in vivo. tGPI-mucins are highly effective in promoting cell recruitment in the pleural cavity of mice primed with IFN-γ-inducing agents but not in naïve mice. Maximal recruitment was observed at a dose between 250 and 1250 ng tGPI-mucins. There was a significant elevation in the levels of MCP-1 in the pleural cavity of primed animals injected with tGPI-mucins, and in vivo neutralization of MCP-1 abolished leukocyte recruitment. Pretreatment with anti-MIP-1α or anti-RANTES had no effect on the recruitment induced by tGPI-mucins. MCP-1 immunoreactivity was detected in pleural macrophages, and macrophages produced MCP-1 in vitro, especially after priming with IFN-γ. Finally, tGPI-mucins induced significant leukocyte recruitment in primed C3H/HeJ but not in TLR2-deficient mice. Together, our results suggest that T. cruzi-derived GPI-mucins in conjunction with IFN-γ may drive tissue chemokine production and inflammation and bear a significant role in the pathogenesis of Chagas disease.