(1-]3)-BETA-D-GLUCAN IN CULTURE FLUID OF FUNGI ACTIVATES FACTOR-G, A LIMULUS COAGULATION-FACTOR

Two well-known polysaccharides, (1-->3)-beta-D-glucan and mannan, are major structural components of the fungus cell wall. The G test is a d irect method to measure (1-->3)-beta-D-glucan using a (1-->3)-beta-D-g lucan-sensitive component, factor G, fractionated from the limulus lys ate. The concentration of (1-->3)-beta-D-glucan in culture supernatant s of Candida albicans increased to 1,390.0 pg/ml at 24 hours. The conc entration of mannan also increased parallel with fungal growth. Howeve r, after digestion of supernatants with endo-(1-->3)-beta-D-glucanase, the reactivity to factor G disappeared, although titers of antimannan monoclonal antibody-based latex agglutination were unchanged. Our stu dy demonstrated that cell suspensions of both C. albicans and Cryptocc ocus neoformans activated the limulus factor G, and that not only the conidia form but also the filamentous form of Aspergillus fumigatus re acted with factor G. Various Candida spp. (C. paraspilosis, C. glabrat a, C. tropicalis, C. krusei), Saccharomyces cerevisiae, Rhodotorula ru bra, Trichosporon beigelii, and A. fumigatus released soluble (1-->3)- beta-D-glucan into their culture supernatants, but C. neoformans and C unninghamella bertholletiae showed only a small reaction to the G test during their culture. Our results indicate that the G test is a good method for serodiagnosis of deep mycosis and also as a screening tool for contamination of medical devices, drugs, and experimental material s with (1-->3)beta-D-glucan. (C) 1995 Wiley-Liss, Inc.