TABLE 2.

Neutralization of HIV-1 by CD4i antibodies and antibody fragments (standard neutralization assay B)a

MAbFormatNeutralization (IC50 [nM]) of HIV-1 isolate
SF162 R592HT594 R5X4JR-CSF R5JR-FL R5ADA R5HxB2 X4A-MLVb
X5IgG0.2267>333 (16)>333 (15)>333 (0)1.8>333
Fab2.8283>1,000 (25)>1,000 (13)>1,000 (15)35>1,000
scFv1.71296331,0776371.2>2,000
17bIgG3.1>333 (21)>333 (0)>333 (0)>333 (0)15>333
scFv3.911736957329445>1,160
b12IgG0.462.17.30.76180.07>333
b6IgG0.53>333 (42)>333 (0)>333 (0)>333 (0)0.38>333
  • a Neutralization was assessed on U87.CD4 cells expressing both CCR5 and CXCR4 coreceptors. Coreceptor tropism of the viral isolates is indicated (R5, X4, or R5X4). Where 50% neutralization was not achieved, the percent inhibition at the highest antibody concentration is given in parentheses. IC50, concentration of antibody causing a 50% reduction in viral infection.

  • b As a negative control, pseudovirions expressing the A-MLV env gene were included.