Interleukin 12 as an adjuvant to WI-1 adhesin immunization augments delayed-type hypersensitivity, shifts the subclass distribution of immunoglobulinG antibodies, and enhances protective immunity to Blastomyces dermatitidisinfection

Cell-mediated immunity is pivotal in host resistance to Blastomyces dermati tidis infection. Immunization of mice with the WI-1 adhesin enhances resist ance against experimental pulmonary infection but elicits features of a mix ed T-helper-cell immune response. Immune mice acquire delayed-type hypersen sitivity (DTH) but also high titers of WI-1-specific immunoglobulin G1 (IgG 1) and IgG2b, a result indicative of T-helper-2 cellular immunity. We repor t that interleukin-12, used as an adjuvant for WI-1 immunization, augments DTH, shifts the balance of the T-helper phenotype toward Th1, and enhances resistance to B. dermatitidis infection.