A conserved region at the COOH terminus of human immunodeficiency virus gp120 envelope protein contains an immunodominant epitope.
A highly immunogenic epitope from a conserved COOH-terminal region of the human immunodeficiency virus (HIV) gp120 envelope protein has been identified with antisera from HIV-seropositive subjects and a synthetic peptide (SP-22) containing 15 amino acids from this region (Ala-Pro-Thr-Lys-Ala-Lys-Arg-Arg-Val-Val-Gln-Arg-Glu-Lys-Arg). Peptide SP-22 absorbed up to 100% of anti-gp120 antibody reactivity from select HIV+ patient sera in immunoblot assays and up to 79% of serum anti-gp120 antibody reactivity in competition RIA. In RIA, 45% of HIV-seropositive subjects had antibodies that bound to peptide SP-22. Human anti-SP-22 antibodies that bound to and were eluted from an SP-22 affinity column reacted with gp120 in RIA and immunoblot assays but did not neutralize HIV or inhibit HIV-induced syncytium formation in vitro, even though these antibodies comprised 70% of all anti-gp120 antibodies in the test serum. In contrast, the remaining 30% of SP-22 nonreactive anti-gp120 antibodies did not react with gp120 in immunoblot assays but did not react in RIA and neutralized HIV in vitro. Thus, approximately 50% of HIV-seropositive patients make high titers of nonneutralizing antibodies to an immunodominant antigen on gp120 defined by SP-22. Moreover, the COOH terminus of gp120 contains the major antigen or antigens identified by human anti-gp120 antibodies in immunoblot assays.
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000032:analysis*; D004261:DNA Replication; D000939:Epitopes / Q000032:analysis*; D006678:HIV / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D015483:HIV Antibodies; D006801:Humans; D009500:Neutralization Tests; D010455:Peptides / Q000138:chemical synthesis; D011863:Radioimmunoassay; D014759:Viral Envelope Proteins / Q000032:analysis / Q000276:immunology*; D014779:Virus Replication
D000914:Antibodies, Viral; D000939:Epitopes; D015483:HIV Antibodies; D010455:Peptides; D014759:Viral Envelope Proteins