Abstract

Certain glycolipids (GLs) described only in fungi, not seen in mammals are capable of unleash immunological response or to suppress some cellular functions. Glycolipids extracted from yeast-form P. brasiliensis inhibited lymphocytes proliferative response to ConA in an animal model and are recognized by serum antibodies from patients with paracoccidioidomycosis. In humans, the role of these glycolipids has never been studied. We extracted two main glycolipids from P. brasiliensis yeast cells, monohexosylceramide (CMH) and glycosylinositol-phosphorylceramide (GIPC) containing Pb-2 (Manpα1-3Manpα1-2InsCer), and Pb-3 (Galf beta1-6(Manpα1-3)Manpα1-2InsCer). Chromatography in DEAE-Sephadex column followed by dialysis and chromatography in Silica Gel 60 was used for glycolipids isolation, and for identification. Purity verification was used high-performance thin-layer chromatography (HTPLC), developed in solvent chloroform/methanol/CaCl2 (60:40:9; v/v/v) and stained with primulin-orcinol/H2SO4. PBMCs and monocytes collected from cured individuals of PCM were cultured with CMH (50uM) and GIPCs (25 uM). Lymphocytes proliferation was measured by thymidine incorporation on DNA after PHA (3 days) or gp43 (7 days) stimulus. Monocytes expression of CD80, CD86, HLA-DR TLR2, TLR4, Dectin-1 and CDd1 was measured by flow cytometry. The results show an increase of lymphocyte proliferation by PHA, but in contrast, a decrease in antigen stimulated proliferation when cultured with CMH. Monocytes presented an increased expression of CD80, CD86 and HLA-DR and no alteration in TLR2, TLR4, Dectin-1 and CD1d expression. In conclusion, the glycolipid CMH is able to modulate lymphocyte proliferation, antigen presentation and co-stimulatory molecules by monocytes, suggesting that CMH may be involved in escape mechanisms of the fungus. Further experiments are needed to confirm this hypothesis. The GIPCs glycolipids did not altered any of the analyzed parameters. ਀ Financial support: FAPESP grant # 07/59598-8 and 07/ 58462-9. ਀㰀⼀昀漀渀琀㸀㰀⼀瀀㸀㰀戀爀㸀㰀戀㸀䬀攀礀眀漀爀搀㨀 㰀⼀戀㸀☀渀戀猀瀀㬀䜀氀礀挀漀氀椀瀀椀搀猀Ⰰ 倀⸀ 戀爀愀猀椀氀椀攀渀猀椀猀Ⰰ 䰀礀洀瀀栀漀挀礀琀攀猀 瀀爀漀氀椀昀攀爀愀琀椀漀渀Ⰰ 䴀漀渀漀挀礀琀攀猀㰀⼀琀搀㸀㰀⼀琀爀㸀㰀⼀琀愀戀氀攀㸀㰀⼀琀爀㸀㰀⼀琀搀㸀㰀⼀琀愀戀氀攀㸀㰀⼀戀漀搀礀㸀㰀⼀栀琀洀氀㸀