TABLE 1.

Neutralization sensitivity of SIV clones to SIVmac251 antiserum, monoclonal antibodies, and sCD4

^aThe IC₅₀ for the antiserum and monoclonal antibodies was calculated as the reciprocal dilution of antiserum or ascites required for achieving 50% inhibition of infection with no serum or ascites control, respectively. The IC₅₀ for sCD4 is the concentration required for achieving 50% inhibition of infection with no sCD4 control.

^bThe IC₅₀ could not be achieved at 1:100 dilutions of antiserum or ascites containing the monoclonal antibodies.

^cEpitopes of 5B11 and 7D3 were mapped to CD4 and CCR5 binding sites, respectively (51).