title: Towards irreversible HIV inactivation: stable gp120 binding by nucleophilic antibodies.
abstract: Conventional antibodies react with antigens reversibly. We report the formation of unusually stable complexes of HIV gp120 and nucleophilic antibodies raised by immunization with an electrophilic HIV gp120 analog (E-gp120). The stability of the complexes was evident from their very slow dissociation in a nondenaturing solvent (approximate t(1/2) 18.5 days) and their resistance to dissociation by a denaturant commonly employed to disrupt noncovalent protein-protein binding (sodium dodecyl sulfate). Kinetic studies indicated time-dependent and virtually complete progression of the antibody-gp120 complexes from the initial noncovalent state to a poorly dissociable state. The antibodies to E-gp120 displayed improved covalent reactivity with an electrophilic phosphonate probe compared to control antibodies, suggesting their enhanced nucleophilicity. One of the stably binding antibodies neutralized the infectivity of CCR5-dependent primary HIV strains belonging to clades B and C. These findings suggest the feasibility of raising antibodies capable of long-lasting inactivation of antigens by electrophilic immunization.
authors.affiliation: Chemical Immunology and Therapeutics Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, Texas 77030, USA.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Karle
authors.forename: Yukie
authors.initials: Y
authors.lastname: Mitsuda
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Taguchi
authors.forename: Stephanie
authors.initials: S
authors.lastname: Planque
authors.forename: Maria
authors.initials: M
authors.lastname: Salas
authors.forename: Carl
authors.initials: C
authors.lastname: Hanson
authors.forename: Sudhir
authors.initials: S
authors.lastname: Paul
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D000936:Antigen-Antibody Complex / Q000276:immunology; D006678:HIV / Q000187:drug effects* / Q000276:immunology*; D015483:HIV Antibodies / Q000276:immunology* / Q000494:pharmacology*; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D007700:Kinetics; D051379:Mice; D009500:Neutralization Tests; D011485:Protein Binding; D012967:Sodium Dodecyl Sulfate / Q000378:metabolism; D013816:Thermodynamics; D038301:Virus Inactivation / Q000187:drug effects*
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D012967:Sodium Dodecyl Sulfate