In vitro selection of HIV-1 resistant to an anti-CD4 monoclonal antibody that inhibits virus transcription.
Phase I studies using monoclonal antibodies (mAbs) that bind to the Ig-CDR3-like loop in domain 1 of CD4 (e.g., 13B8-2 mAb) have already been documented for HIV-1-infected patients. In vitro, such mAbs do not inhibit virus to cell fusion but are able to inhibit virus envelope-mediated syncytia formation. Moreover, these mAbs inhibit Tat-induced activation of HIV-1 promoter and HIV-1 transcription in infected CD4+ cells. Here, we report the selection of escaped mutant virus or viruses derived from HIV-1Lai capable of replicating in vitro in the presence of concentrations of 13B8-2 mAb, that usually inhibit HIV-1Lai particle production. The escaped mutant virus or viruses, termed HIV-1Lai13EM, kept the major enzymatic restriction sites found in HIV-1Lai and remained sensitive to anti-CD4 mAb-, soluble CD4-, and recombinant gp120-mediated inhibition of syncytia formation. Possible genetic changes affecting the tat gene or the 5' long terminal repeat (LTR) were investigated. Partial sequence analysis of HIV-1Lai13EM and a control HIV-1Lai grown for 85 days in CEM cells, demonstrated that the first tat exon of these two viruses encoded identical proteins. Although a point mutation G>A was frequently encountered (6 of 13 sequences) in the LTRs of HIV-1Lai13EM at position -188 within the negative regulatory element (NRE), this mutation did not confer the escape mutant phenotype. Our study indicates that the mutant phenotype probably requires genetic changes in a region or regions outside the LTRs.
Coudronnière
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N
Laboratoire d'Immunologie des Infections Rétrovirales, Institut de Biologie, Montpellier, France.
David
C
C
Hirn
M
M
Devaux
C
C
D019380:Anti-HIV Agents / Q000494:pharmacology*; D001483:Base Sequence; D015704:CD4 Antigens / Q000276:immunology*; D002459:Cell Fusion / Q000187:drug effects; D003001:Cloning, Molecular; D004352:Drug Resistance, Microbial / Q000235:genetics; D015756:Genes, tat; D015699:HIV Envelope Protein gp120 / Q000494:pharmacology; D016325:HIV Long Terminal Repeat / Q000235:genetics; D015497:HIV-1 / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D009500:Neutralization Tests; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA
D019380:Anti-HIV Agents; D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120