Immunologic Impairment in Mice Treated Intravenously with Killed Coccidioides Immitis Spherules: Suppressed Response to Intramuscular Doses

Open Access
Publisher Website
Google Scholar
Abstract
Summary: Subsequent to intramuscular (i.m.) vaccination with killed Coccidioides immitis spherules, mice developed strong immunity and survived intranasal challenge doses of arthrospores in the magnitude of 200 LD50. This was not the case in mice vaccinated intravenously (i.v.); a majority succumbed to challenge with 5 LD50. Furthermore, i.m. vaccinated mice also succumbed to the latter challenge when small amounts of antigen were administered i.v. either concurrently with, before, or up to 35 days after the i.m. doses. The nature of the deficient response was in general accord with that described for immunologic unresponsiveness in the adult animal and was readily demonstrable with 120 µg of killed spherules. The i.v. administration of antigen adversely affected immunity development, not its expression, because the immunity of preimmunized mice could not be impaired by the above-noted treatment. Immunity suppression was produced also with spherule walls, the major locus of the immunogens. Similarly, a suppressed response followed the i.v. injection of endospores in mice vaccinated i.m. with either the spherule or the endospore phase of the fungus. However, neither Saccharomyces cerevisiae nor Cryptococcus neoformans, given i.v., induced a deficient response in spherule-vaccinated mice nor did a weakly immunogenic soluble cellular fraction impair it significantly. The data suggested that suppression was mediated by immunospecific substances and was not influenced by the size of the structures introduced i.v. which varied from 1 to 2 µ (endospores) to 15 to 20 µ (spherules).