Detection of antibodies to Candida albicans germ tubes during experimental infections by different Candida species.

Identification and characterization of Candida albicans germ tube-specific antigens may be of relevance for the serodiagnosis of invasive candidiasis since they could be the basis for the development of new diagnostic tests. In this study, we have identified two antigens of 180 and >200 kDa in the cell wall of C. albicans germ tubes which are responsible for the induction of antibodies to C. albicans germ tubes. Antigens of similar molecular masses have been demonstrated in the cell walls of the Candida species C. stellatoidea, C. parapsilosis, C. guilliermondii, C. tropicalis, and C. krusei, but not C. glabrata. The kinetics of the antibody responses to C. albicans germ tubes were studied in rabbits infected with different Candida species. Although these antibodies were detected in rabbits infected with all Candida species except C. glabrata, the kinetics of the antibody responses to C. albicans germ tubes induced by the Candida species studied were different. Both the highest titer and the earliest response of antibodies to C. albicans germ tubes were observed in rabbits infected with either of the two serotypes of C. albicans used. However, the time needed to elicit the antibodies to C. albicans germ tubes can be reduced as the result of an anamnestic antibody response. The results presented in this study show that a test designed to detect antibodies against C. albicans germ tube antigens may be suitable for the diagnosis of infections caused by most of the medically important Candida species.