Diphtheria toxin(DT) is the major virulence factor of the disease diphtheria. The recent reappearance of this disease in a number of countries of Europe, Asia, Africa, and South America, underscores it's continuing significance as a worldwide health problem. The long-term goals of this proposal are to characterize fully the cell surface receptor which DT utilizes to gain illicit entry into toxin-sensitive host cells and to understand completely the interaction between the toxin and its receptor. The investigators earlier discovered that DT binds to the transmembrane/precursor form of heparin-binding EGF-like growth factor (HB-EGF). They have recently identified the EGF-like domain of the cell surface of HB-EGF precursor as the region where the toxin binds and have shown that the soluble/mature form of HB-EGF inhibits binding of the toxin to the native toxin receptor on cells. The first specific aim is to determine the role of the cytoplasmic domain of the toxin receptor. The second specific aim is to characterize the functional interactions of the extracellular domain of the receptor with the toxin and with other receptor-associated proteins. The third specific aim is to characterize the toxin-binding site of the receptor employing a combination of site-directed mutagenesis and X-ray crystallography. The fourth specific aim is to produce transgenic mice bearing the HB-EGF precursor in order to determine whether this precursor can act an a DT receptor in vivo and to test the ability of recombinant mature HB-EGF to ameliorate intoxication by DT in this novel DT-sensitive experimental animal model. The results of this proposed project, in addition to extending our knowledge on toxin:receptor interactions, may provide a new kind of therapy for clinical diphtheria in which mature HB-EGF would replace equine horse anti-DT serum as the antidote of choice.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI016805-21
Application #
6372978
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Program Officer
Klein, David L
Project Start
1980-04-01
Project End
2002-12-31
Budget Start
2001-05-01
Budget End
2002-12-31
Support Year
21
Fiscal Year
2001
Total Cost
$310,574
Indirect Cost
Name
University of Texas Sw Medical Center Dallas
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
800771545
City
Dallas
State
TX
Country
United States
Zip Code
75390
Cha, Jeong-Heon; Chang, Mee Young; Richardson, James A et al. (2003) Transgenic mice expressing the diphtheria toxin receptor are sensitive to the toxin. Mol Microbiol 49:235-40
Cha, Jeong-Heon; Brooke, Joanna S; Chang, Mee Young et al. (2002) Receptor-based antidote for diphtheria. Infect Immun 70:2344-50
Brooke, Joanna S; Cha, Jeong-Heon; Eidels, Leon (2002) Latent transforming growth factor beta-binding protein-3 and fibulin-1C interact with the extracellular domain of the heparin-binding EGF-like growth factor precursor. BMC Cell Biol 3:2
Cha, J H; Brooke, J S; Ivey, K N et al. (2000) Cell surface monkey CD9 antigen is a coreceptor that increases diphtheria toxin sensitivity and diphtheria toxin receptor affinity. J Biol Chem 275:6901-7
Brooke, J S; Cha, J H (2000) Molecular characterization of key diphtheria toxin:receptor interactions. Biochem Biophys Res Commun 275:374-81
Cha, J H; Brooke, J S; Eidels, L (1999) Hamster diphtheria toxin receptor: a naturally occurring chimera of monkey and mouse HB-EGF precursors. Biochem Biophys Res Commun 254:325-9
Brooke, J S; Cha, J H; Eidels, L (1998) Diphtheria toxin:receptor interaction: association, dissociation, and effect of pH. Biochem Biophys Res Commun 248:297-302
Cha, J H; Brooke, J S; Eidels, L (1998) Toxin binding site of the diphtheria toxin receptor: loss and gain of diphtheria toxin binding of monkey and mouse heparin-binding, epidermal growth factor-like growth factor precursors by reciprocal site-directed mutagenesis. Mol Microbiol 29:1275-84
Hooper, K P; Eidels, L (1996) Glutamic acid 141 of the diphtheria toxin receptor (HB-EGF precursor) is critical for toxin binding and toxin sensitivity. Biochem Biophys Res Commun 220:675-80
Hooper, K P; Eidels, L (1995) Localization of a critical diphtheria toxin-binding domain to the C-terminus of the mature heparin-binding EGF-like growth factor region of the diphtheria toxin receptor. Biochem Biophys Res Commun 206:710-7

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