Infection remains the most frequent illness of man and one of the most common causes of death. The investigations proposed here seek to gain understanding of the physiology of host defense against infections, especially bacterial and fungal infection. The ultimate goals of this research are the more effective prevention and management of infections in the normal and compromised host and the eventual manipulation of certain functions of the immune system to enhance its protective effects. The focus of these studies is the oxygen-dependent mechanisms by which phagocytic cells (neutrophils and macrophages) kill microorganisms. In particular, the projects proposed here seek to gain knowledge about the molecular nature of the events that comprise the """"""""respiratory burst system"""""""": binding of the stimulus (organism) to the phagocyte membrane ->initiation and transduction of a bio-chemical signal -> triggering of the enzyme responsible for converting oxygen to its microbicidal metabolites. Most of the projects explore elements of the process of signal transduction in phagocytes. The biochemical events under scrutiny will be compared in normal and activated macrophages, which are capable of markedly increased activity of the respiratory burst, and in neutrophils """"""""primed"""""""" for such activity by exposure in vitro to a variety of agents, especially endotoxin and cytokines. The intent is to gain understanding of the molecular basis for upregulation of the respiratory burst and of the mechanisms responsible for triggering the respiratory burst enzyme. Specific projects will compare different priming agents and relate changes induced in the time course of the respiratory burst to changes in intracellular free Ca2+ (at baseline and stimulated, in individual cells with laser cytometry and in cell populations), in five major products of membrane phosphoinositide remodelling, and in activities of phospholipases C and A2. The molecular basis of the priming induced by brief exposure of macrophages and neutrophils to proteases will be sought by similar analyses. The effect of protein malnutrition on the activation of macrophages will be studied in mice. Improved understanding of the mechanisms responsible for the respiratory burst of phagocytic cells might permit its eventual pharmacologic modulation.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI024782-06
Application #
3138016
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Project Start
1986-09-01
Project End
1992-08-31
Budget Start
1991-09-01
Budget End
1992-08-31
Support Year
6
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Children's Hospital of Philadelphia
Department
Type
DUNS #
073757627
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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Marodi, L; Tournay, C; Kaposzta, R et al. (1998) Augmentation of human macrophage candidacidal capacity by recombinant human myeloperoxidase and granulocyte-macrophage colony-stimulating factor. Infect Immun 66:2750-4
Knickelbein, R G; Seres, T; Lam, G et al. (1997) Characterization of multiple cysteine and cystine transporters in rat alveolar type II cells. Am J Physiol 273:L1147-55
Seres, T; Ravichandran, V; Moriguchi, T et al. (1996) Protein S-thiolation and dethiolation during the respiratory burst in human monocytes. A reversible post-translational modification with potential for buffering the effects of oxidant stress. J Immunol 156:1973-80
Moriguchi, T; Seres, T; Ravichandran, V et al. (1996) Diamide primes neutrophils for enhanced release of superoxide anion: relationship to S-thiolation of cellular proteins. J Leukoc Biol 60:191-8
Knickelbein, R G; Ingbar, D H; Seres, T et al. (1996) Hyperoxia enhances expression of gamma-glutamyl transpeptidase and increases protein S-glutathiolation in rat lung. Am J Physiol 270:L115-22
Kutsumi, H; Kawai, K; Johnston Jr, R B et al. (1995) Evidence for participation of vicinal dithiols in the activation sequence of the respiratory burst of human neutrophils. Blood 85:2559-69
Marodi, L; Kaposzta, R; Campbell, D E et al. (1994) Candidacidal mechanisms in the human neonate. Impaired IFN-gamma activation of macrophages in newborn infants. J Immunol 153:5643-9
Chai, Y C; Ashraf, S S; Rokutan, K et al. (1994) S-thiolation of individual human neutrophil proteins including actin by stimulation of the respiratory burst: evidence against a role for glutathione disulfide. Arch Biochem Biophys 310:273-81
Forehand, J R; Johnston Jr, R B (1994) Chronic granulomatous disease: newly defined molecular abnormalities explain disease variability and normal phagocyte physiology. Curr Opin Pediatr 6:668-75

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