Characterization of recombinant gp120 and gp160 from HIV-1: binding to monoclonal antibodies and soluble CD4.
We compared four preparations of recombinant HIV-1 envelope glycoprotein: mammalian (Chinese hamster ovary cells) gp120 (Celltech); baculovirus gp120 from American Biotechnologies Inc. (ABT) and from MicroGeneSys (MGS); and baculovirus gp160 (Institute of Virology, Oxford, UK). Each envelope glycoprotein binds to a neutralizing monoclonal antibody (MAb) directed against the V3 loop, confirming the integrity of this type-specific neutralization epitope. MGS gp120 binds abnormally well to a MAb which recognizes an epitope preferentially exposed on denatured gp120. Consistent with this finding, MGS gp120 binds to soluble CD4 (sCD4) with an affinity 50-100-fold lower than that of Celltech gp120. The affinity of Celltech gp120 from sCD4 is 2.3 nM, indistinguishable from that of gp120 extracted from HIV-1 virions. Baculovirus gp120 (ABT) and gp160 also have a high affinity for sCD4. A significant proportion of anti-gp120 antibodies in HIV-positive human sera recognize epitopes that are dependent on the mammalian glycosylation pattern, and a human HIV-positive serum inhibits the binding of mammalian gp120 to sCD4 five- to 10-fold more potently than it inhibits baculovirus gp120 binding to sCD4.
Chester Beatty Laboratories, Institute of Cancer Research, London, UK.
J P
JP
Moore
J A
JA
McKeating
I M
IM
Jones
P E
PE
Stephens
G
G
Clements
S
S
Thomson
R A
RA
Weiss
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001665:Binding Sites; D015704:CD4 Antigens / Q000276:immunology*; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D015686:Gene Products, env / Q000276:immunology*; D006678:HIV / Q000276:immunology; D015488:HIV Antigens / Q000276:immunology*; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D019302:HIV Envelope Protein gp160; D006679:HIV Seropositivity / Q000276:immunology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007304:Insect Viruses / Q000276:immunology; D007313:Insecta / Q000235:genetics; D011498:Protein Precursors / Q000276:immunology*; D015728:Receptors, HIV / Q000276:immunology; D012995:Solubility; D014614:Vaccines, Synthetic / Q000276:immunology
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D015686:Gene Products, env; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; D019302:HIV Envelope Protein gp160; D011498:Protein Precursors; D015728:Receptors, HIV; D014614:Vaccines, Synthetic