Monoclonal antibodies to a CD4 peptide derivative which includes the region corresponding to an immunoglobulin CDR3: evidence of the involvement of pre-CDR3-related region in HIV-1 and host cell interaction.
A CD4 peptide of amino acid residues 68-130 [CD4(68-130)], which had the capacities to inhibit HIV-1 replication and HIV-1-induced syncytium formation, was used as an immunogen for the preparation of mAb. The mAbs prepared were classified into at least five types (I-V) in terms of their recognition sites by ELISA using various kinds of smaller CD4 peptides. Among them, the type I mAb no. 35 recognizing amino acid residues 72-84, which lies just before the region corresponding to an immunoglobulin third complementarity-determining region (CDR3), showed the strongest effects in reducing both HIV-1 infection and HIV-1-induced syncytium formation, although a large amount of no. 35 mAb was necessary to reduce such HIV-1 activities compared with those of anti-Leu-3a and OKT4A mAbs which recognize CD4 epitopes near a portion corresponding to an immunoglobulin CDR2. Western blot analysis showed that the reactivities of CD4 molecule in CD4-positive cells or sCD4 molecule with types I-V mAbs were stronger than that with anti-Leu-3a mAb. Flow cytometry showed that no. 35 mAb was faintly reactive with native CD4 molecule on cell surface at the concn showing the inhibitory effects on HIV-1 infection and syncytium formation. In addition, a smaller peptide CD4(66-92), one of the good epitope peptides for no. 35 mAb, also showed strong inhibitory effect on HIV-1 infection as well as a weaker inhibitory effect on syncytium formation. These results suggest that, in addition to the CD4 CDR2-related region, the pre-CDR3-related region is also involved in the early events of the interactions between the host cell and HIV-1.
Ohki
K
K
Institute of Immunological Science, Hokkaido University, Sapporo, Japan.
Kimura
T
T
Ohmura
K
K
Morikawa
Y
Y
Jones
I M
IM
Azuma
I
I
Ikuta
K
K
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D001667:Binding, Competitive; D015153:Blotting, Western; D015704:CD4 Antigens / Q000737:chemistry / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D015726:Giant Cells / Q000276:immunology; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1; D006790:Host-Parasite Interactions / Q000276:immunology*; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D007074:Immunoglobulin G / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D007074:Immunoglobulin G; D007135:Immunoglobulin Variable Region; D010446:Peptide Fragments