Role of specific determinants in mannan of Candida albicans serotype A in adherence to human buccal epithelial cells

Abstract

Candida albicans serotype A (C. albicans A) possesses a specific antigen, designated antigen 6, which resides in mannans on the cell surface. To determine the role of the mannan moiety of the C. albicans cell wall in adherence to buccal epithelial cells, we used antigen 6-deficient mutants which had been isolated by screening with an agglutinating monoclonal antibody against antigen 6 (MAb-6). 'H nuclear magnetic resonance spectral analysis of the purified mannans from the mutants showed a loss of the signals related to the 1-linkage of the side chains. Moreover, acetolyzed fragments of the mutant mannans showed a decreased amount of mannohexaose and mannopentaose. The mutant yeast cells exhibited significantly reduced ability to adhere both to exfoliated buccal epithelial cells and to a human buccal cell line. A number of strains of C. albicans A, C. tropicalis, and C. glabrata, all of which bear antigen 6, showed significantly higher adherence to the cell line than did those of C. albicans serotype B, which lack antigen 6. The whole mannan from the C. albicans A parent inhibited the adherence of C. albicans A to epithelial cells dose dependently, whereas mannan from a mutant strain did not. Moreover, C. albicans A treated with MAb-6 or polyclonal factor 6 serum showed reduced adherence. A close correlation was found between adhesive ability and agglutinability with MAb-6 in the C. albicans A parent, the antigenic mutants, and their spontaneous revertants. These results suggest that so far as mannan adhesin is concerned, serotype A-specific determinants are largely involved in the mechanisms of adherence of C. albicans A to human buccal epithelial cells.

Existence of novel β‐1,2 linkage‐containing side chain in the mannan of Candida lusitaniae, antigenically related to Candida albicans serotype A

“…Because the b-1,2-linked mannose unit is present among the pathogenic fungi only in the mannan of the genus Candida and the b-1,2 linkage-containing side chains behave as strong antigens, many workers [18][19][20][21][22][23][24][25] have produced monoclonal antibodies to b-1,2-linked mannose units to protect against candidiasis, for the serodiagnosis of candidiasis, or for the identification of mechanisms of Candida infection. Furthermore, studies have indicated the b-1,2-linked mannose units participate in the adherence of Candida cells to mammalian cells as the first step in infection [26][27][28]. Poulain and his coworkers [29][30][31][32] reported that the b-1,2 linkage-containing oligosaccharides and phospholipomannans induce cytokine production and may act as a virulent factor in candidiasis.…”

Adherence and proliferation of keratinocytes cultured with Candida albicans

“…1 Although the infections were mainly reported in Australia, Africa, North America, Europe and Thailand, 1,2 few reports including a cutaneous infection have been reported in Japan. 3 We report a case of N. transvalensis mycetoma on the left arm of a healthy male, with repeated recurrences for 25 years without visceral metastasis.…”

“…With regard to the interaction between keratinocytes and C. albicans, mannan adhesion is possibly involved in the adhesion mechanism. 3 However, secreted aspartic proteinases (SAPs), one of the major virulence attributes of C. albicans, should be considered as another factor in their interaction. 4 Further explorations using neutralizing antibodies against antigen 6, mannan and SAPs should be made to shed light on this problem.…”

Selection and pathogenicity of Candida albicans in HIV infection

“…N-acetylgluc?samine, mannosamine, glucosamine and galactosamine (Collins-Lech et al, 1984;Critchley and Douglas, 1987b). Also, a number of putative adhesins of C. albicans have been studied including cell wall chitin (Segal et al, 1982;Lehrer et al, 1988) lipids (Ghannoum et al, 1986), complement receptors (Gilmore et al, 1987;Alaei et al, 199~), fibronectin adhesins (Klotz et al, 1994), mannan (Sandin, 1987;Miyakawa et al, 1992), proteins (Calderone and ScheId, 1987;Critchley and Douglas, 1987a), and mannoproteins (Tosh and Douglas, 1992;I,?bert-Bernard et .al, 1995). Evidence suggests that C. albl~ans rnannoprotems are the principle adhesins responsible for a~hcslOn to host cells and these have been partially characterised (Tosh and C. albicans…”