Abstract

Histoplasma capsulatum is a facultative intracellular parasite of mononuclear phagocytic cells. Peritoneal macrophages from mice immunized by sublethal infection restrict the intracellular growth of H. capsulatum. Splenocytes from immune mice arm normal macrophages to suppress intracellular growth of the fungus. This activation of normal macrophages is mediated by lymphokines found in supernatants from cultures of antigen-stimulated immune splenocytes or those from concanavalin-A (ConA) stimulated T cell hybridomas. The lymphokines have no direct effect on H. capsulatum but act by stimulating macrophages to suppress fungal growth. Current evidence indicates that gamma interferon (IFN-Gamma) is the lymphokine that stimulates macrophages to inhibit H. capsulatum. Macrophage suspensions are comprised of subpopulations some of which are responsive and others of which are unresponsive to lymphokine stimulation. Responsive cells synthesize a set of unique peptides when stimulated by lymphokines, and prevention of protein synthesis in macrophages antagonizes their abiliity to inhibit intracellular growth of H. capsulatum. The use of a macrophage cell line in place of the more heterogeneous native peritoneal populations would appear to offer advantages in further studies on mechanisms of intracellular inhibition.
The Specific Aim of the work described in this proposal is to identify molecular bases for the inhibition of intracellular growth of H. capsulatum within macrophages activated by IFN-Gamma.
The aim will be pursued by analyzing the antihistoplasma state induced by recombinant IFN-Gamma in resident peritoneal macrophages of C57/B16 mice and in a responsive macrophage cell line, P388D1. The analysis will be conducted by: (i) measuring the intracellular growth of H. capsulatum within the cells, (ii) recording the occurrence and characteristic unique peptides formed by cells stimulated by IFN-Gamma, and (iii) assessing the potential role of the peptides in the antihistoplasma state of the macrophages.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI022963-03
Application #
3134718
Study Section
Bacteriology and Mycology Subcommittee 1 (BM)
Project Start
1985-12-01
Project End
1988-11-30
Budget Start
1987-12-01
Budget End
1988-11-30
Support Year
3
Fiscal Year
1988
Total Cost
Indirect Cost

  Institution

Name
University of California Los Angeles
Department
Type
Schools of Medicine
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095

  Publications

Perepnikhatka, V; Fischer, F J; Niimi, M et al. (1999) Specific chromosome alterations in fluconazole-resistant mutants of Candida albicans. J Bacteriol 181:4041-9
Janbon, G; Sherman, F; Rustchenko, E (1999) Appearance and properties of L-sorbose-utilizing mutants of Candida albicans obtained on a selective plate. Genetics 153:653-64
Janbon, G; Sherman, F; Rustchenko, E (1998) Monosomy of a specific chromosome determines L-sorbose utilization: a novel regulatory mechanism in Candida albicans. Proc Natl Acad Sci U S A 95:5150-5
Rustchenko, E P; Howard, D H; Sherman, F (1997) Variation in assimilating functions occurs in spontaneous Candida albicans mutants having chromosomal alterations. Microbiology 143 ( Pt 5):1765-78
Villarete, L; de Fries, R; Kolhekar, S et al. (1995) Impaired responsiveness to gamma interferon of macrophages infected with lymphocytic choriomeningitis virus clone 13: susceptibility to histoplasmosis. Infect Immun 63:1468-72
Lane, T E; Otero, G C; Wu-Hsieh, B A et al. (1994) Expression of inducible nitric oxide synthase by stimulated macrophages correlates with their antihistoplasma activity. Infect Immun 62:1478-9
Lane, T E; Wu-Hsieh, B A; Howard, D H (1994) Antihistoplasma effect of activated mouse splenic macrophages involves production of reactive nitrogen intermediates. Infect Immun 62:1940-5
Nakamura, L T; Wu-Hsieh, B A; Howard, D H (1994) Recombinant murine gamma interferon stimulates macrophages of the RAW cell line to inhibit intracellular growth of Histoplasma capsulatum. Infect Immun 62:680-4
Lane, T E; Wu-Hsieh, B A; Howard, D H (1993) Gamma interferon cooperates with lipopolysaccharide to activate mouse splenic macrophages to an antihistoplasma state. Infect Immun 61:1468-73
Wu-Hsieh, B A; Lee, G S; Franco, M et al. (1992) Early activation of splenic macrophages by tumor necrosis factor alpha is important in determining the outcome of experimental histoplasmosis in mice. Infect Immun 60:4230-8

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