title: Evaluation of purified H and M antigens of histoplasmin as reagents in the complement fixation test.
abstract: Complement-fixation (CF) tests were performed with purified H and M antigens, histoplasmin, and Histoplasma capsulatum whole cell yeast phase antigen using sera of 126 patients with proven or suspected histoplasmosis. Specific titers for either H or for M antibody were obtained with the individual purified antigens; the highest titers were comparable to those obtained with histoplasmin. However, in sera containing only anti-M antibody, the titers obtained with the purified M antigen were 2 to 16 times those obtained with the histoplasmin or yeast phase antigens. The CF test for either H or M antibody was 4 to 32 times as reactive as the agar-gel microimmunodiffusion test; in general precipitin lines were obtained with either H or M antigens from sera with CF titers greater than or equal to 8. With sera containing H antibody, there was an excellent correlation between the CF titers obtained with purified M antigen and histoplasmin. The correlations of CF titers with H antigen and either histoplasmin or yeast phase antigen were very low.
mesh_terms: D000908:Antibodies, Fungal / Q000032:analysis; D000946:Antigens, Fungal / Q000302:isolation & purification*; D001759:Blastomycosis / Q000276:immunology; D003168:Complement Fixation Tests; D006658:Histoplasma / Q000276:immunology; D006659:Histoplasmin / Q000032:analysis*; D006660:Histoplasmosis / Q000276:immunology; D006801:Humans; D005779:Immunodiffusion
chemical_list: D000908:Antibodies, Fungal; D000946:Antigens, Fungal; D006659:Histoplasmin