The chimeric mouse-human anti-CD4 Fab 13B8.2 expressed in baculovirus inhibits both antigen presentation and HIV-1 promoter activation

Article type: Research Article

Authors: Bès, Cédric^a | Cerutti, Martine^c | Briant-Longuet, Laurence^b | Bresson, Damien^a | Peraldi-Roux, Sylvie^a | Pugnière, Martine^a | Mani, Jean-Claude^a | Pau, Bernard^a | Devaux, Christian^b | Granier, Claude^a | Devauchelle, Gérard^c | Chardès, Thierry^{c; *}

Affiliations: [a] CNRS UMR 5094, Faculté de Pharmacie, 15 Avenue Charles Flahault, 34060 Montpellier, France | [b] CNRS EP 2104, Institut de Biologie, 34060 Montpellier, France | [c] INRA-CNRS UMR 5087, Laboratoire de Pathologie Comparée, 30380 Saint-Christol-Lez-Alès, France

Correspondence: [*] Corresponding author. Tel.: +33 4 67 548 604; Fax: +33 4 67 548 610; E-mail: chardes@pharma.univ-montp1.fr.

Abstract: The anti-CD4 mAb 13B8.2, directed against the CDR3-like loop of the D1 domain of CD4, inhibits signal transduction pathways leading to both T cell activation and HIV replication. VH9/DSP2/JH2 andκ12-13/Jκ2 rearrangements, corresponding to genes encoding the heavy and light chain variable regions of the 13B8.2 mAb, were inserted into baculovirus cassettes upstream from pre-installed human Fdγ1 and κ genes, respectively. After expression in insect cells, a complete correctly-processed Fab was secreted into the culture medium; it was protein-G immunopurified with a yield of 5 mg/L. The chimeric Fab 13B8.2 showed anti-CD4 binding activity with an affinity value of 3.3 nM and recognized the same region on the CDR3-like loop as the parental mAb. The mouse-human Fab inhibited IL2 secretion following antigen presentation and displayed a strong capacity to prevent HIV-1 promoter activation. Taken together, these results indicate that the chimeric Fab retained a major part of the parental 13B8.2 mAb properties and suggest that it might be a valuable therapeutic tool.

DOI: 10.3233/HAB-2001-10203

Journal: Human Antibodies, vol. 10, no. 2, pp. 67-76, 2001