A major clinical problem in infectious diseases in the United States is the recognition, diagnosis, control, and treatment of serious, life-threatening infections in immunocompromised individuals. Many patients with treatable underlying illnesses succumb to opportunistic pathogens before the patient's original problem can be controlled. Nocardia asteroides, a normal inhabitant of the soil, is an important opportunistic pathogen that frequently causes serious pulmonary and systemic infections in compromised patients. Little is known concerning the precise mechanisms controlling nocardial pathogenesis. Current data suggest that much of the organism's virulence is due to a variety of substances associated with the bacterial cell envelope. These components are important in: selective organ tropisms of the bactyeria within the host; altering phagocyte function by inhibiting phagosome-lysosome fusion and reducing lysosomal enzyme activity; neutralization of bactericidal oxidative products by phagocytes; toxicity towards host cells; and the ability of the nocardial cell to grow within host cells and function as a faultative intracellular pathogen. Cell wall and cytoplasmic components of N. asteroides will be fractionated by standard biochemical procedures. By utilizing hybridoma technology, monoclonal antibodies will be produced against those specific cellular fractions and then the antibodies will be utilized to purify further the specific antigens. By utilizing in vitro studies with either murine macrophages or human phagocytes and in vivo models in mice, these purified, highly specific antibodies and antigens will permit identification of the components of the cells that are important in each aspect of nocardial pathogenesis. These results will permit recognition of substances that may be utilized for better immunodiagnostic procedures. Further, they will lay a foundation to permit immunoprophylactic and immunotherapeutic augmentation of host resistance in immunocompromised hosts.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
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Bacteriology and Mycology Subcommittee 1 (BM)
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University of California Davis
Schools of Medicine
United States
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Beaman, Blaine L; Tam, Stanley (2008) An unusual murine behavior following infection with log-phase Nocardia asteroides type 6 strain GUH-2 (Nocardia cyriacigeorgica GUH-2). Microbes Infect 10:840-3
Hyland, K; Beaman, B L; LeWitt, P A et al. (2000) Monoamine changes in the brain of BALB/c mice following sub-lethal infection with Nocardia asteroides (GUH-2). Neurochem Res 25:443-8
Beaman, B L; Canfield, D; Anderson, J et al. (2000) Site-specific invasion of the basal ganglia by Nocardia asteroides GUH-2. Med Microbiol Immunol 188:161-8
Friedman, C S; Beaman, B L; Chun, J et al. (1998) Nocardia crassostreae sp. nov., the causal agent of nocardiosis in Pacific oysters. Int J Syst Bacteriol 48 Pt 1:237-46
Beaman, B L; Beaman, L (1998) Filament tip-associated antigens involved in adherence to and invasion of murine pulmonary epithelial cells in vivo and HeLa cells in vitro by Nocardia asteroides. Infect Immun 66:4676-89
Ioneda, T; Beaman, B L (1996) Thermospray mass spectral analyses of corynomycolic acids and their derivatives. Chem Phys Lipids 83:123-30
Beaman, B L (1996) Differential binding of Nocardia asteroides in the murine lung and brain suggests multiple ligands on the nocardial surface. Infect Immun 64:4859-62
Alcendor, D J; Chapman, G D; Beaman, B L (1995) Isolation, sequencing and expression of the superoxide dismutase-encoding gene (sod) of Nocardia asteroides strain GUH-2. Gene 164:143-7
Beaman, L; Beaman, B L (1994) Differences in the interactions of Nocardia asteroides with macrophage, endothelial, and astrocytoma cell lines. Infect Immun 62:1787-98
Beaman, B L; Beaman, L (1994) Nocardia species: host-parasite relationships. Clin Microbiol Rev 7:213-64

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