Rapid and reliable method for production of a specific Paracoccidioides brasiliensis immunodiffusion test antigen.

Previously published methods to produce Paracoccidioides brasiliensis antigens for serological tests have yielded antigens of inconsistent quality and have involved the use of special semisynthetic media and growth periods of 1 to 3 months to yield suitable reagents. A simple procedure that uses commercially available potato glucose agar and either SABHI broth (Difco Laboratories) or Trypticase soy broth (BBL Microbiology Systems) inoculated with the mycelial form of P. brasiliensis consistently yielded high-titer antigens in 2 weeks or less. This new method permits the almost exclusive production of an antigen identical to the specific E antigen described by Yarzabal (Yarzabal et al., Sabouradia 14:275-280, 1976) and the apparently equivalent specific antigen 1 described by Restrepo and Moncada (A. Restrepo and L. H. Moncada, Appl. Microbiol. 28:138-144, 1974). In the immunodiffusion test, the rapidly produced antigen demonstrated a sensitivity of 90% by detecting antibody in sera from 103 of 114 proven cases of paracoccidioidomycosis. The specificity of this antigen was 100% because none of 139 sera from patients with heterologous mycotic diseases demonstrated diagnostic precipitins against the P. brasiliensis antigen. In the complement fixation tests, the rapidly produced antigen was not as suitable as the one prepared by the method of Restrepo-Moreno and Schneidau (A. Restrepo-Moreno and J. D. Schneidau, Jr., J. Bacteriol. 93:1741-1748, 1967).