Therapeutic administration of soluble CD4 is theoretically an attractive means of competitively inhibiting the binding of HIV to its primary cellular receptor, but was a failure in clinical trials more than a decade ago. We propose the creation of novel CD4 analogs to overcome the stoichiometric and affinity limitations of that initial approach. Using electrophilic phosphonate ester probes, we recently discovered that HIV gp120 contains activated nucleophilic amino acids. In the proposed studies, CD4 (and CD4 peptide mimetic, s) will be modified by the addition of activated electrophilic phosphonates, which will result in specific covalent bonding of these constructs to nucleophilic sites on gp120 on the surface of HIV virions. Such an """"""""infinite"""""""" affinity interaction will result in irreversible blocking of HIV infectivity. The concept is based on our successful analogous work on catalytic antibodies, in which nucleophilic immunoglobulin sites bind to electrophiles in the substrate ligand. Thus the Specific Aims of this proposed Innovation Grant are (1) to create covalently reactive CD4 and CD4 peptide mimetics; (2) to determine the potency, intra- and intersubtype breadth and irreversibility of HIV neutralization and inhibition of cell-to-cell spread of HIV infection via cell fusion by these covalently reactive CD4 analogues; (3) to demonstrate the irreversibility of binding of the constructs to gp120 and to intact virions; and (4) to determine the role in the virus neutralization that isplayed by the covalency (vs. conventional noncovalent antibody binding). Successful results should lead tofollow-up testing in primate models and human clinical trials. The proposed studies may also help to definecovalent and pseudocovalent forces as a novel mechanism of protein-ligand interactions. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI058684-02
Application #
6847164
Study Section
AIDS Molecular and Cellular Biology Study Section (AMCB)
Program Officer
Voulgaropoulou, Frosso
Project Start
2004-02-01
Project End
2007-01-31
Budget Start
2005-02-01
Budget End
2007-01-31
Support Year
2
Fiscal Year
2005
Total Cost
$107,000
Indirect Cost
Name
Public Health Foundation Enterprises
Department
Type
DUNS #
082199324
City
City of Industry
State
CA
Country
United States
Zip Code
91746
Nishiyama, Yasuhiro; Planque, Stephanie; Mitsuda, Yukie et al. (2009) Toward effective HIV vaccination: induction of binary epitope reactive antibodies with broad HIV neutralizing activity. J Biol Chem 284:30627-42
Mitsuda, Yukie; Planque, Stephanie; Hara, Mariko et al. (2007) Naturally occurring catalytic antibodies: evidence for preferred development of the catalytic function in IgA class antibodies. Mol Biotechnol 36:113-22
Planque, Stephanie; Mitsuda, Yukie; Taguchi, Hiroaki et al. (2007) Characterization of gp120 hydrolysis by IgA antibodies from humans without HIV infection. AIDS Res Hum Retroviruses 23:1541-54
Nishiyama, Yasuhiro; Karle, Sangeeta; Planque, Stephanie et al. (2007) Antibodies to the superantigenic site of HIV-1 gp120: hydrolytic and binding activities of the light chain subunit. Mol Immunol 44:2707-18
Nishiyama, Yasuhiro; Karle, Sangeeta; Mitsuda, Yukie et al. (2006) Towards irreversible HIV inactivation: stable gp120 binding by nucleophilic antibodies. J Mol Recognit 19:423-31