Generation and characterization of neutralizing human monoclonal antibodies against human immunodeficiency virus type 1 Tat antigen.
The human immunodeficiency virus Tat regulatory protein is essential for virus replication and pathogenesis. From human peripheral blood mononuclear cells of three Tat toxoid-immunized volunteers, we isolated five Tat-specific human monoclonal antibodies (HMAbs): two full-length immunoglobulin G (IgG) antibodies and three single-chain fragment-variable (scFv) antibodies. The two IgGs were mapped to distinct epitopes within the basic region of Tat, and the three scFvs were mapped to the N-terminal domain of Tat. The three scFvs were highly reactive with recombinant Tat in Western blotting or immunoprecipitation, but results were in contrast to those for the two IgGs, which are sensitive to a particular folding of the protein. In transactivation assays, scFvs were able to inhibit both active recombinant Tat and native Tat secreted by a transfected CEM cell line while IgGs neutralized only native Tat. These HMAbs were able to reduce viral p24 production in human immunodeficiency virus type 1 strain IIIB chronically infected cell lines in a dose-dependent manner.
Moreau
Emmanuel
E
INSERM EMI 0334, Hôpital St-Louis, F-75010 Paris, France.
Hoebeke
Johan
J
Zagury
Daniel
D
Muller
Sylviane
S
Desgranges
Claude
C
D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology; D000918:Antibody Specificity; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D015696:Gene Products, tat / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000276:immunology*; D015483:HIV Antibodies / Q000276:immunology*; D015488:HIV Antigens / Q000737:chemistry / Q000276:immunology*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000494:pharmacology; D007135:Immunoglobulin Variable Region / Q000276:immunology / Q000494:pharmacology; D009500:Neutralization Tests; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000276:immunology; D015533:Transcriptional Activation / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects; D054322:tat Gene Products, Human Immunodeficiency Virus
D000911:Antibodies, Monoclonal; D015696:Gene Products, tat; D015483:HIV Antibodies; D015488:HIV Antigens; D007074:Immunoglobulin G; D007135:Immunoglobulin Variable Region; D011994:Recombinant Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus