Cross-reaction between the mycelial galactomannas of three Hormodendrum strains and the mannans of two Candida albicans strains of different serotypes, A and B

Detection of Candida sp. mannan antigen by indirect ELISA-inhibition. In vitro crossed reactivity among mannans obtained from C. albicans A, C. albicans B, and C. tropicalis

We have obtained mannans from four Candida species: C. albicans A, C. albicans B and C. tropicalis; anti-mannan sera against C. albicans A, C. albicans B and C. tropicalis were obtained by immunizing rabbits subcutaneously with the respective yeast extract. The efficacy of these sera in reacting with mannans obtained from three Candida sp. has been proven by indirect ELISA-inhibition. Any of three immune sera can be used to detect mannan antigen from the three Candida sp. tested. This confirms the existence of crossed reactivity and the possibility of detecting mannan antigen in serum from patients infected by different Candida sp., although we had only one immune serum and one Candida mannan.

Variability in expression of a cell surface determinant on Candida albicans as evidenced by an agglutinating monoclonal antibody

The expression of a surface immunodeterminant of Candida albicans was investigated with an agglutinating immunoglobulin M monoclonal antibody. The 96 strains of C. albicans tested, of which 76% were recent clinical isolates, were capable of expressing the antigen. The antigen was also produced by strains of Candida tropicalis and Torulopsis glabrata, but not by other yeast species. Expression of the surface immunodeterminant in C. albicans varied as a function of growth as indicated by agglutinin reactions and indirect immunofluorescence tests. When yeast cells were tested with the agglutinin, three patterns of reactivity were observed. In general, cells in the early logarithmic phase were less reactive than cells in the mid-logarithmic phase. Antigen expression, as determined by agglutinin reactivity, was also influenced by the nutritional composition of the growth medium, and in general, cells from broth cultures were usually more reactive than cells grown on solid media. The antigen was solubilized from the cell surface of C. albicans by hot 1 M NaCl. These water-soluble extracts were capable of binding antibody, and a single precipitin band formed when soluble antigen was reacted with the monoclonal antibody in an Ouchterlony double-diffusion test. Whole cell preparations and hot NaCl extracts from yeast strains which did not agglutinate when mixed with the antibody also did not absorb the agglutinin from solution. These data indicate that the expression of surface antigens on C. albicans is a dynamic process which may be influenced by a number of environmental factors. The use of monoclonal antibodies may allow characterization of surface antigens presented to the host during candidiasis.