Blastomyces dermatitidis antigen-induced lymphocytes reactivity in human blastomycosis.

Because of the unavailability of a suitable antigen, specific in vitro lymphocyte reactivity has not been investigated in persons who have had systemic blastomycosis. Twelve persons who had recovered from blastomycosis were evaluated, and all were found to exhibit strongly positive and apparently specific in vitro cellular responses to an alkali-soluble, water-soluble extract of Blastomyces dermatitidis yeast-phase cell walls. Significant lymphocyte transformation induced by this soluble antigen occurred with cells from persons who had recovered from blastomycosis as much as 16 years previously, indicating long-lasting cell-mediated immunity to B. dermatitidis. A simple new in vitro test, lymphocyte migration inhibition, also made it possible to distinguish persons who had had blastomycosis and recovered from persons who had never had the disease. Two in vitro tests of cell-mediated immunity in which the alkali-soluble, water-soluble extract of B. dermatitidis yeast-phase cell walls was employed were highly discriminating. Tests with this antigen may be of value in delineating the epidemiology of blastomycosis and in assessing the prognosis of individual cases.