Treatment of serum with supernatants from cultures of Candida albicans reduces its serum-dependent phagocytosis

Abstract

Candida albicans is a potent activator of the complement system, and heat labile opsonins produced by activation of C3 (C3b and iC3b) enhance phagocytosis of C. albicans mediated by complement receptors. In this study we treated mouse serum with supernatants from cultures of a protease producer strain of C. albicans and evaluated the ability of this serum to enhance phagocytosis of C. albicans. Cell-free supernatants from cultures of C. albicans were concentrated 5 fold and added to mouse serum for 30 min at 37ºC, before using this serum for opsonization of glutaraldehyde-fixed yeast cells. We observed that normal mouse serum increased about 3 fold the phagocytosis of C. albicans by mice peritoneal macrophages, whereas supernatant-treated serum did not increase phagocytosis. This effect of supernatants on serum was prevented by addition of pepstatin (5 µg/ ml; an inhibitor of C. albicans acid proteases) to the medium. Serum treated with supernatants from cultures of a protease-deficient mutant of C. albicans also increased about 3 fold phagocytosis of the yeast. These results suggest that a protease produced by C. albicans causes proteolysis of serum opsonins, thereby reducing the phagocytosis of the yeast.

Resposta imune a Candida albicans

“…Entre estes, citam-se os receptores de manose; receptores semelhantes a Toll (TLRs); receptores de varredura e receptor dectina-1 (UNDERHILL; OZINSKY, 2002). Os fagócitos expressam também receptores para complemento (CR) e anticorpos (FcR), e vários pesquisadores têm demonstrado que a fagocitose de C. albicans por fagócitos mononucleares é aumentada quando as leveduras estão opsonizadas com soro normal BALISH, 1997;GAZIRI et al, 1999;SANTOS et al, 2002).…”

The Role of Candida Albicans and Streptococcus MutansSpent Culture Supernatant in Single and Dual-Species Biofilm

“…Frequently, S. mutans and C. albicans are found together in oral biofilms [1]. Thus, considering the polymicrobial characteristic of dental caries, investigating the way that interactions between microbes affect biofilm formation and cell morphology is essential to understanding the pathogenesis of this disease [5]. Therefore, this study aimed to evaluate the influence of C. albicans and S. mutans SCS, combined or not, in the biofilm formation of these microorganisms grown in their singlespecies and dual-species biofilms.…”