Identification of an N-linked glycan in the V1-loop of HIV-1 gp120 influencing neutralization by anti-V3 antibodies and soluble CD4.
Glycosylation is necessary for HIV-1 gp120 to attain a functional conformation, and individual N-linked glycans of gp120 are important, but not essential, for replication of HIV-1 in cell culture. We have constructed a mutant HIV-1 infectious clone lacking a signal for N-linked glycosylation in the V1-loop of HIV-1 gp120. Lack of an N-linked glycan was verified by a mobility enhancement of mutant gp120 in SDS-gel electrophoresis. The mutated virus showed no differences in either gp120 content per infectious unit or infectivity, indicating that the N-linked glycan was neither essential nor affecting viral infectivity in cell culture. We found that the mutated virus lacking an N-linked glycan in the V1-loop of gp120 was more resistant to neutralization by monoclonal antibodies to the V3-loop and neutralization by soluble recombinant CD4 (sCD4). Both viruses were equally well neutralized by ConA and a conformation dependent human antibody IAM-2G12. This suggests that the N-linked glycan in the V1-loop modulates the three-dimensional conformation of gp120, without changing the overall functional integrity of the molecule.
Laboratory for Infectious Diseases, Hvidovre Hospital, Denmark.
G J
GJ
Gram
A
A
Hemming
A
A
Bolmstedt
B
B
Jansson
S
S
Olofsson
L
L
Akerblom
J O
JO
Nielsen
J E
JE
Hansen
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D001483:Base Sequence; D015704:CD4 Antigens / Q000276:immunology*; D002460:Cell Line; D002470:Cell Survival; D003208:Concanavalin A / Q000276:immunology; D006031:Glycosylation; D015483:HIV Antibodies / Q000276:immunology; D015488:HIV Antigens / Q000096:biosynthesis; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D015497:HIV-1 / Q000737:chemistry* / Q000276:immunology / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D011134:Polysaccharides / Q000737:chemistry; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000276:immunology
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D015483:HIV Antibodies; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; C059761:HIV envelope protein gp120 (135-148); C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments; D011134:Polysaccharides; D011994:Recombinant Proteins; C076613:recombinant soluble CD4; D003208:Concanavalin A