Table 1.

Comparison of antibody inhibitory concentration and level in serum

AntibodyInhibitory concn (μg/ml)a:Concn in serum (μg/ml)b
IC99IC90IC50
HIVIG>20,0002,3984655,346
2F5>200172192
2G12>2001857175
2F5/2G122141216, 244
HIVIG/2F5/2G1212217,712, 200, 224
  • a The IC50, IC90, and IC99 were derived from the neutralization dose-response curves in Fig. 1 (e.g., the calculated IC99 of 21 μg/ml for 2F5/2G12 indicates a 99% neutralization effect when the two MAbs were present together at 21 μg/ml each). For the triple-antibody combination, the ICs listed are for MAbs; the corresponding HIVIG concentration is 100-fold higher.

  • b Mean antibody concentration in serum on the day of virus challenge for each antibody. When antibody combinations were administered, the mean level of each antibody is listed in order, corresponding to the antibody description in the left-hand column. For the triple-antibody combination, values are the mean of results with six animals; other antibody groups included three animals each.