Human C-Reactive Protein (CRP) is the prototype of a number of proteins which share the property of increasing their plasma concentration following injury and which are collectively referred to as """"""""acute-phase proteins"""""""". The objective of the proposed research is to define the biologic role of CRP. Our working hypothesis is that the function of CRP relates to its ability to specifically recognize foreign pathogens and damaged or necrotic cells of the host and to initiate their elimination by interacting with the complement system and with phagocytic cells. We propose to approach our objectives by pursuing the following specific aims: 1) Define the structural determinants of the phosphocholine-binding site of CRP. In a first stage we will construct recombinant SV40-CRP viruses and utilize them to express the protein in mammalian cells. In a second stage we will map the topology and chemical nature of the binding site by using site-directed mutagenesis. 2) Define the structural determinants of the effector functions of CRP. Both the C1q binding/complement activating site and the site reacting with the CRP receptor on human neutrophils will be characterized. Initial definition of the sites will utilize monoclonal antibodies and more detailed characterization site-directed mutagenesis. 3) Further study the in-vivo protective effects of CRP against bacterial infections in the murine model. We are particularly interested in defining in-vivo synergistic effects between CRP and antibodies, as well as between CRP and complement opsonins. These combined studies will lead to an increased understanding of host- defense mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AI015607-13
Application #
3480837
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Project Start
1979-01-01
Project End
1993-08-31
Budget Start
1991-09-01
Budget End
1993-08-31
Support Year
13
Fiscal Year
1991
Total Cost
Indirect Cost
Name
University of Alabama Birmingham
Department
Type
Schools of Medicine
DUNS #
004514360
City
Birmingham
State
AL
Country
United States
Zip Code
35294
Szalai, A J; Agrawal, A; Greenhough, T J et al. (1999) C-reactive protein: structural biology and host defense function. Clin Chem Lab Med 37:265-70
Szalai, A J; van Ginkel, F W; Dalrymple, S A et al. (1998) Testosterone and IL-6 requirements for human C-reactive protein gene expression in transgenic mice. J Immunol 160:5294-9
Agrawal, A; Lee, S; Carson, M et al. (1997) Site-directed mutagenesis of the phosphocholine-binding site of human C-reactive protein: role of Thr76 and Trp67. J Immunol 158:345-50
Szalai, A J; Briles, D E; Volanakis, J E (1996) Role of complement in C-reactive-protein-mediated protection of mice from Streptococcus pneumoniae. Infect Immun 64:4850-3
Szalai, A J; Briles, D E; Volanakis, J E (1995) Human C-reactive protein is protective against fatal Streptococcus pneumoniae infection in transgenic mice. J Immunol 155:2557-63
Agrawal, A; Volanakis, J E (1994) Probing the C1q-binding site on human C-reactive protein by site-directed mutagenesis. J Immunol 152:5404-10
Agrawal, A; Xu, Y; Ansardi, D et al. (1992) Probing the phosphocholine-binding site of human C-reactive protein by site-directed mutagenesis. J Biol Chem 267:25353-8
Kilpatrick, J M; Gresham, H D; Griffin Jr, F M et al. (1987) Peripheral blood mononuclear leukocytes release a mediator(s) that induces phagocytosis of C-reactive protein-coated cells by polymorphonuclear leukocytes. J Leukoc Biol 41:150-5
Horowitz, J; Volanakis, J E; Briles, D E (1987) Blood clearance of Streptococcus pneumoniae by C-reactive protein. J Immunol 138:2598-603
Gresham, H D; Clement, L T; Lehmeyer, J E et al. (1986) Stimulation of human neutrophil Fc receptor-mediated phagocytosis by a low molecular weight cytokine. J Immunol 137:868-75

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