Antibody responses raised against a conformational V3 loop peptide of HIV-1.
The amino acid sequence of the principal neutralizing determinant (PND) of 224 cases of human immunodeficiency virus type 1 (HIV-1) was determined and the most frequently occurring sequence was used as a peptide antigen for studying virus-specific antibody responses. In our present study, a linear peptide of the most frequent PND was first synthesized and then oxidized to create a disulfide-bridged loop conformation. Then, in order to construct a macromolecular structure for the purpose of increasing antigenicity, the synthetic peptide was conjugated to a core peptide. We compared the immunogenicity of the disulfide-bridged loop PND peptide antigen (AG4) and the linear PND peptide antigen (AG5). After immunizing rabbits 5 and 6 times with both peptides, the results obtained using ELISA revealed that AG4 (conformational-loop type) was more capable of inducing a high titer of antigen-specific antibodies than was AG5 (linear type). Despite an amino acid sequence homology of 72%, a 1:8 dilution of serum raised against AG4 inhibited 81.9% of HIV-1IIIB-mediated cell fusion, suggesting that conformational V3 loop peptide is able to elicit an antibody response which is strongly HIV-1-specific.
D000595:Amino Acid Sequence; D000818:Animals; D015483:HIV Antibodies / Q000096:biosynthesis*; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology*; D011487:Protein Conformation; D011817:Rabbits
D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments