Confocal microscopy, with P. brasiliensis cell wall stained with calcofluor white indicates two places of MEST-3 binding, i) extensive and internal to calcofluor labeling, i.e. plasma membrane,

and ii) discrete external as well as co-labeling with calcofluor, these preliminary data led us to suggest a new conceptual model of GSL arrangements in yeast forms where microdomain-like regions containing GIPCs could also be located at the external surface of the cell wall. Further work to substantiate this concept model is under investigation in our laboratory aiming an extensive comprehension see more of fungal glycosphingolipid enriched microdomains regarding their composition, surface localization, role in signaling processes and possible role in host cell binding and infection. This study and others have shown that specific GIPCs are found in a large variety of pathogenic fungi [6, 7]. In some cases, those GIPCs are recognized by sera from patients with paracoccidioidomycosis, histoplasmosis or aspergillosis [8–10, 13–15, 32], indicating that GIPCs are immunogenic and able to induce the production of human antibodies during fungal infections. The broad

Idoxuridine distribution of GIPCs in pathogenic fungi and the antifungal activity MS-275 clinical trial of monoclonal antibodies directed to GIPCs indicate that these molecules may represent potential targets for the development of new therapeutical approaches based on induction of protective antibodies. Conclusion The fine specificity of MEST-3 was assessed by inhibition assays using different methyl-glycosides, disaccharides and oligosaccharides. Only Manα1→3Man and the JSH-23 cell line glycoinositol Manα1→3Manα1→2Ins, from Pb-2, were able to inhibit, by

about 95%, MEST-3 binding to Pb-2 antigen of P. brasiliensis. The epitope recognized by MEST-3 was defined as Manα1→3Manα1→2Ins; this structure was already described in a variety of pathogenic fungi [5–11, 15–17, 19, 23]. Studies using mAbs MEST-3 and MEST-1, as fungal growth inhibitors showed that anti-GIPCs mAbs presented a strong inhibitory activity on growth, differentiation and colony formation of P. brasiliensis, H. capsulatum, and S. schenckii. On the other hand, no statistically significant inhibition was observed with anti-GlcCer (MEST-2). These results strongly suggest that mAbs directed to particular glycosphingolipids are able to interfere on fungal growth and differentiation.