Investigation of anti-WI-l adhesin antibody-mediated protection in experimental pulmonary blastomycosis

Infection with Blastomyces dermatitidis elicits strong antibody responses t o the surface adhesin WI-1, The antibodies are directed chiefly against the adhesive domain, a 25-amino-acid repeat, Tandem-repeat-specific monoclonal antibodies (mAbs) were studied for their opsonic activity in vitro and the ir capacity to adoptively transfer protection in murine experimental blasto mycosis, mAbs to WI-1 enhanced binding and entry of B. dermatitidis yeasts into J774.16 cells but did not enhance killing or growth inhibition of the yeast. Passive transfer of 8 mAbs to WI-1 into 3 different inbred strains o f mice also did not improve the course of experimental infection and someti mes worsened it. mu-deficient mice were more resistant to experimental blas tomycosis than were intact littermates, and passive transfer of the mAbs in to these mice did not protect them against experimental infection. Thus, an tibody to WI-1 does not appear to improve the outcome of murine blastomycos is and may enhance the infection.