TABLE 2.

Pre- and postadsorption neutralization ID50 values for two broadly neutralizing sera with wild-type (WT) or coreceptor binding region (CD4i) mutant gp120 I420R-coupled beads

SerumVirusID50% Neutralization activity
Blankagp120WTbgp120I420Rcgp120 directeddgp120I420R directedegp120 neut. to CD4ifTotal neut. to CD4ig
B7B5HXBc213,5755441,579968888
BaL.016,4173741,48194771817
JRFL2,28124094189593431
PVO.041,62826794784425042
RW20.21,38717936887731614
ZA012.292441442325359148
45HXBc21,5782601,09784306453
BaL.011,4204532,45568010068
RW20.226311522956137743
  • a Samples adsorbed on blank Dynabeads.

  • b Samples adsorbed on Dynabeads coated with YU2 gp120WT protein.

  • c Samples adsorbed on Dynabeads coated with YU2 gp120I420R protein (CD4i knockout mutation).

  • d Percent reduction in ID50 by gp120WT relative to blank beads as an indication of the proportion of gp120-specific neutralization against a particular virus isolate.

  • e Percent reduction in ID50 by gp120I420R relative to blank beads as an indication of the proportion of non-CD4i-directed neutralization.

  • f Percentage of total gp120-directed neutralization (neut.) that is via the CD4i; i.e., [(percentage of gp120-directed neutralization − percentage of gp120I420R-directed neutralization)/percentage of gp120-directed neutralization] (values 20% or greater are shown in boldface type).

  • g Percentage of total serum neutralization (neut.) that is via the CD4i; i.e., (percentage of gp120 neutralization that is CD4i directed × percentage of gp120-directed neutralization).