The chimeric mouse-human anti-CD4 Fab 13B8.2 expressed in baculovirus inhibits both antigen presentation and HIV-1 promoter activation.
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 and Vkappa12-13/Jkappa2 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 Fdgamma1 and Ckappa 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.
Bès
C
C
CNRS UMR 5094, Faculté de Pharmacie, 15 Avenue Charles Flahault, 34060 Montpellier, France.
Cerutti
M
M
Briant-Longuet
L
L
Bresson
D
D
Peraldi-Roux
S
S
Pugnière
M
M
Mani
J C
JC
Pau
B
B
Devaux
C
C
Granier
C
C
Devauchelle
G
G
Chardès
T
T
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology*; D016367:Baculoviridae / Q000235:genetics; D015704:CD4 Antigens / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry; D015488:HIV Antigens / Q000276:immunology*; D015497:HIV-1 / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D014775:Virus Activation / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D000939:Epitopes; D015488:HIV Antigens; D007140:Immunoglobulin Fab Fragments; D011993:Recombinant Fusion Proteins