The Capsular Polysaccharides GXM and GXMGal from Cryptococcus neoformans Modulate Macrophages Infected with...

Leishmania spp. are obligatory intracellular parasites that primarily infect macrophages. The macrophage immune response plays a pivotal role in determining the control or progression of infection. "M1-like" macrophages mediate parasite clearance through the production of nitric oxide, pro-inflammatory cytokines, and reactive oxygen species, whereas "M2-like" macrophages contribute to infection progression by exerting anti-inflammatory effects. The capsular polysaccharides Glucuronoxylomannan (GXM) and glucuronoxylomannogalactan (GXMGal) from Cryptococcus neoformans are capable of immunomodulating the macrophage response. GXM exhibits immunoregulatory activity, whereas GXMGal induces a pro-inflammatory response. Although the activity of these polysaccharides has been studied in cryptococcosis, their immunomodulatory potential in other infectious models remains largely unexplored. Here, we investigated the effects of GXM and GXMGal on Leishmania major infection in murine peritoneal macrophages. Murine peritoneal macrophages were infected with L. major and, 24 h post-infection, treated with 50 μg of either GXM or GXMGal. Our data revealed that GXM treatment enhanced L. major infection, while GXMGal treatment had no significant effect on the parasitic load in infected macrophages.