Reaction of Candida albicans cells of different morphology index with monoclonal antibodies specific for the hyphal form.

Two monoclonal antibodies (MAbs), 3D9 with reported specificity for Candida albicans hyphae, and 3B7 with reported specificity for morphological forms of C. albicans found in vivo, were tested by indirect immunofluorescence with C. albicans cells that were grown in 12 different environments (four different culture media incubated at various temperatures) and whose cellular morphology was estimated in terms of morphology index (Mi). Both MAbs reacted strongly with cells with Mi greater than 3.0, i.e., with pseudohyphal and hyphal forms, but in Eagle's medium at 26 degrees C and in a modified Sabouraud's broth medium at 30 degrees C, some reactivity was also found with cells of lower Mi (i.e., yeast forms). Therefore, it was concluded that the hyphal phenotype and the epitopes reactive with the MAbs were co-expressed but that the epitopes could also be expressed independently of the hyphal phenotype. The results confirm the propensity of C. albicans for variation of its surface antigenic composition.