Neutralization properties of Envs carrying Y681 and H681 in different genetic backgrounds.

*Represents fold-increase in sensitivity of Env-pseudotyped viruses expressing H681 compared to those expressing Y681.†The minimum DKW motif necessary for 2F5 recognition is absent.The overall differences in sensitivity of Envs expressing H681 with that of Y681 to sCD4 and 4E10 MAb were significant (P = 0.0002 and P = 0.008).TND-L669 and TND_L669S [44] as well as Q461.e2, Q461.e2 (TA) and Q461.e2 (IV) [43] that were earlier reported to enhance sensitivity of HIV-1 to neutralizing antibodies were tested in parallel. Fold differences in neutralization sensitivities are given in parentheses.