Histoplasma capsulatum and V beta a mice: cellular immune responses and susceptibility patterns

Abstract

Certain strains of mice, designated V beta a, have a deletion of the gene segments encoding the beta chain of the T-cell receptor variable region. These mice do not express 40 to 50% of the T-cell receptor V beta chains. In this study, we examined the influence of this deletion on susceptibility to Histoplasma capsulatum. In addition, H. capsulatum-injected V beta a mice were tested for their capacity to generate T-cell dependent responses to H. capsulatum antigens. Susceptibility profiles of V beta a mice, SWR/J (H-2q), SJL/J (H-2s) and C57L-(H-2b), were compared to V beta b strains, C57BL/6 (H-2b) and DBA/l (H-2q), following intravenous (IV) injection of sublethal and lethal inocula of H. capsulatum yeast cells. One week after injection of 6 x 10(5) yeast cells, the spleens of SWR/J, SJL/J and C57L mice contained 5- to 7-fold fewer colony forming units (CFU) than spleens of C57BL/6 mice. Approximately 50% fewer CFU of H. capsulatum were recovered from the spleens of DBA/l mice compared to those from C57BL/6 animals. Subsequently, groups of mice were challenged IV with either 1.5 x 10(7) or 7.5 x 10(6) yeast cells and observed for 30 days. Survival of SWR/J,SJL/J, C57L and DBA/l mice was significantly prolonged compared to C57BL/6 mice. V beta a and DBA/l mice injected with viable H. capsulatum yeast cells mounted a delayed-type hypersensitivity response to an extract from the cell wall and cell membrane of yeast cells and to HIS-62, a purified antigen derived therefrom.(ABSTRACT TRUNCATED AT 250 WORDS)