Abstract

The long term objective of this research is to define in biochemical terms the microbicidal mechanisms of phagocytes in order to better understand the causes of opportunistic infection and to seek new means for its prevention and therapy. With their ability to ingest and kill potential pathogens, human neutrophils (PMN) are key components of host defenses against infection. We recently discovered that human PMN contain three antimicrobial peptides, named HNP-1, HNP-2 and HNP-3. The peptides, collectively referred to as """"""""defensins"""""""", were sequenced. They exhibit homology to a family of six antimicrobial peptides abundant in rabbit granulocytes and/or lung macrophages, the """"""""lysosomal cationic proteins"""""""" of Zeya and Spitznagel.
The specific aims are as follows: a. to determine the antimicrobial spectrum of the human defensins by studying their ability to kill or inactivate aerobic and anaerobic bacteria, yeast-phase fungi and selected viruses. b. to identify and analyse factors that modulate the antimicrobial activity of defensins. c. to examine the interactions of these peptides with other potentially antimicrobial constituents of human neutrophils, including lysozyme, BPI, myeloperoxidase and selected reactive oxygen intermediates. d. to establish the intracellular location of defensins in PMN and assess both their intracellular translocation to phagolysosomes and their extracellular release. e. to ascertain the mechanisms whereby defensins act on microorganisms. f. to develop and apply qualitative and quantitative procedures to measure the defensin content of normal PMN and determine whether PMN defensin deficiency underlies the occurrence of certain, presently unexplained infections in man. The methodology for performing these studies includes cellular fractionation, chromatographic purification and various electrophoretic, immunocytochemical and immunoquantitative (ELISA) techniques. Specific details and examples are provided in the body of the proposal.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI022839-02
Application #
3134422
Study Section
Bacteriology and Mycology Subcommittee 1 (BM)
Project Start
1985-12-01
Project End
1988-11-30
Budget Start
1986-12-01
Budget End
1987-11-30
Support Year
2
Fiscal Year
1987
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

Doherty, Timothy; Waring, Alan J; Hong, Mei (2006) Peptide-lipid interactions of the beta-hairpin antimicrobial peptide tachyplesin and its linear derivatives from solid-state NMR. Biochim Biophys Acta 1758:1285-91
Tang, Ming; Waring, Alan J; Lehrer, Robert I et al. (2006) Orientation of a beta-hairpin antimicrobial peptide in lipid bilayers from two-dimensional dipolar chemical-shift correlation NMR. Biophys J 90:3616-24
Tang, Ming; Waring, Alan J; Hong, Mei (2005) Intermolecular packing and alignment in an ordered beta-hairpin antimicrobial peptide aggregate from 2D solid-state NMR. J Am Chem Soc 127:13919-27
Mani, Rajeswari; Waring, Alan J; Lehrer, Robert I et al. (2005) Membrane-disruptive abilities of beta-hairpin antimicrobial peptides correlate with conformation and activity: a 31P and 1H NMR study. Biochim Biophys Acta 1716:11-8
Buffy, Jarrod J; Waring, Alan J; Hong, Mei (2005) Determination of peptide oligomerization in lipid bilayers using 19F spin diffusion NMR. J Am Chem Soc 127:4477-83
Buffy, Jarrod J; McCormick, Melissa J; Wi, Sungsool et al. (2004) Solid-state NMR investigation of the selective perturbation of lipid bilayers by the cyclic antimicrobial peptide RTD-1. Biochemistry 43:9800-12
Mani, Rajeswari; Buffy, Jarrod J; Waring, Alan J et al. (2004) Solid-state NMR investigation of the selective disruption of lipid membranes by protegrin-1. Biochemistry 43:13839-48
Owen, S M; Rudolph, D; Wang, W et al. (2004) A theta-defensin composed exclusively of D-amino acids is active against HIV-1. J Pept Res 63:469-76
Wang, Wei; Owen, Sherry M; Rudolph, Donna L et al. (2004) Activity of alpha- and theta-defensins against primary isolates of HIV-1. J Immunol 173:515-20
Buffy, Jarrod J; Hong, Teresa; Yamaguchi, Satoru et al. (2003) Solid-state NMR investigation of the depth of insertion of protegrin-1 in lipid bilayers using paramagnetic Mn2+. Biophys J 85:2363-73

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