Characteristics of the pulmonary cellular immune response to two strains of Blastomyces dermatitidis in the mouse.

In order to assess the cellular responses in the lung in murine pulmonary blastomycosis, serial lung lavages were performed in normal BALB/cByJ mice that had received an intranasal inoculation with 1 of 2 strains of Blastomyces dermatitidis of opposite virulence. The virulent strain, ATCC 26199, induced an increasing number of neutrophils recovered from the lung lavages. An early peak of incoming neutrophils was seen at 1 to 2 days, followed by a more rapid accumulation of intraalveolar neutrophils, until by the ninth day after infection, 80% of the cells recovered from the mice were neutrophils. In contrast, the avirulent strain, ATCC 26197, induced the same degree (20%) of neutrophil influx on Days 1 and 2. Thereafter, the percentage of neutrophils consistently declined, so that by Day 6 after inoculation, the differential counts were normal. The total number of cells recovered from the mice challenged with the virulent strain did not increase significantly until Day 4; then the total number of cells consistently increased until the experiment was terminated on Day 14. The total number of cells obtained from the mice challenged with the avirulent organism never exceeded the normal range. To assess the effects of nonviable inert particles, mice were given Sephadex G-25 beads by the intranasal route, and the total number of cells recovered from the lung lavage fluid and the differential counts were determined. The peak neutrophil influx occurred 6 h after aspiration of the beads, compared with 24 to 48 h with the fungi.(ABSTRACT TRUNCATED AT 250 WORDS)