Exoantigen test for differentiation of Exophiala jeanselmei and Wangiella dermatitidis isolates from other dematiaceous fungi.

Concentrated (25X) exoantigens of 105 isolates of pathogenic and saprophytic dematiaceous fungi and 3 isolates of Sporothrix schenckii were analyzed by the microimmunodiffusion method. The reagents used were nonadsorbed and adsorbed sera produced in New Zealand rabbits. One set of rabbits was immunized with soluble antigens of a 1-month-old culture of Exophiala jeanselmei (ATCC 34123), and the other set was immunized with soluble antigens from a culture of Wangiella dermatitidis (ATCC 28869). The reference antigens were 25X-concentrated exoantigens of the above cultures. This exoantigen test permitted the differentiation of E. jeanselmei and W. dermatitidis from one another as well as from other Exophiala species, Fonsecaea species, Phialophora species, Cladosporium species, Rhinocladiella species, and Sporothrix schenckii by presence or absence of lines of identity or of partial identity, or lines of nonidentity. Using adsorbed serum eliminated the problems with cross-reactivity seen with nonadsorbed serum. Thus, with an adsorbed serum as the reagent, it was possible to presumptively differentiate E. jeanselmei and W. dermatitidis from one another and from other dematiaceous fungi.