Towards irreversible HIV inactivation: stable gp120 binding by nucleophilic antibodies.
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.
Nishiyama
Yasuhiro
Y
Chemical Immunology and Therapeutics Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, Texas 77030, USA.
Karle
Sangeeta
S
Mitsuda
Yukie
Y
Taguchi
Hiroaki
H
Planque
Stephanie
S
Salas
Maria
M
Hanson
Carl
C
Paul
Sudhir
S
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*
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D012967:Sodium Dodecyl Sulfate