Immunogenic properties of nondisrupted and disrupted spherules of<i>Coccidioides immitis</i>in mice

Abstract

The immunogenicity for mice of the spherule-endospore phase of Coccidioides immitis was investigated in respect of the duration of immune response and the stability, locus, and specificity of the antigens. Formalinized vaccine retained potency during 20 months' storage at 4°C in the presence of formalin or after treatment with chloroform. Induced immunity did not decline during a 97-day interval between vaccination and challenge and was effective against lethal challenge with an heterologous strain of C. immitis. Nonspecific resistance to Cryptococcus neoformans or Pseudomonas (Malleomyces) pseudomallei was not induced by vaccination. Immunogenicity resided primarily, but not exclusively, in the wall structure of disrupted spherules; some activity was demonstrable in the soluble protoplasmic moiety by the use of an adjuvant. A procedure for disrupting the spherules and isolating distinguishable wall fragments is described.