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Table 4 Neutralization of SHIV-2873Nip by plasma samples of SHIVIG recipients

From: Passive immunization of macaques with polyclonal anti-SHIV IgG against a heterologous tier 2 SHIV: outcome depends on IgG dose

Group (mg/kg of SHIVIG) Monkey Peak vRNA load (copies/ml) Day of 1stchallenge
Highest % of neutralization SHIVIG plasma IC50(μg/ml)
Group 1 RVv-12 4,500 90.1 12.9
(400) RQv-12 342,850 85.7 10.9
Group 2 RZu-11 201,700 74.7 (91.8) 6.0
(675) RRs-12 229,600 88.8 (95.6) 4.8
Group 3 RWt-12 61,750 58.5 6.2
(25) RNz-11 1,032,600 66.7 3.3
  1. The highest percent of neutralization was seen at a plasma dilution of 1:6. Values in parentheses represent the highest % of neutralization reached for RZu-11 and RRs-11 at plasma dilutions 1:54 and 1:18, respectively. SHIVIG plasma IC50 concentrations were determined using the concentration of SHIVIG in RM plasma on the day of challenge and the dilution of the same plasma sample showing 50% of neutralization in PBMC assay. Neutralization assays were performed at least in triplicate. Measurements of viral loads were performed in duplicate.