Antigenic differences between mannoproteins of germ tubes and blastospores of Candida albicans

To determine the nature of germ tube-specific antigens of Candida albicans, procedures for intrinsically labeling cell wall antigens metabolically were developed. Blastospores or germ tubes labeled either in their proteins with L-[35S]methionine or in mannose-containing carbohydrates with D[2-3H]mannose contained surface components similar to those found previously with 125I-labeled organisms. Germ tube-specific determinants, were found on a 200-kilodalton protein in digests from germ tubes, whereas a component of similar molecular size in blastospore extracts reacted weakly or not at all with germ tube-specific antibody. In addition, a glycan fraction prepared from germ tubes reacted with the unadsorbed anti-C. albicans polyvalent antibody but not with the germ tube-specific antibody, suggesting that the germ tube-specific determinants are not carbohydrates.