Evaluation of plasma vs. antibodies in the 24/1/14 extended incubation PBMC assay. The neutralization profiles of the plasma are compared with those for their respective mAbs for the 24/1/14 extended incubation PBMC assay in Table 6 . The mAbs clearly neutralized a much more restricted range of isolates than the plasma. 242315-HJ plasma and HJ16 mAb both neutralized the subtype C isolate VI829, the subtype D CI 13 and two of the three CRF02_AG isolates, VI 1090 and CA18. 314994-HGN plasma and HGN194 mAb as well as 529552-HK plasma and HK20 mAb neutralized SF162 (B) and 92Br025 (C) while HGN194 mAb also neutralized VI 191 (A) and 89.6 (B). In Table 5 . Neutralization profile of patient plasma in different HIV-1 neutralization assays. addition, a number of qualitative discrepancies were observed in that growth of some viruses was strongly inhibited by the mAb, but enhanced by the plasma (e.g. subtype A 92RW009 with 242315-HJ plasma versus HJ16 mAb) or vice-versa (e.g. CRF02 strains with 314994-HGN plasma versus HGN194 mAb). This type of inconsistency was also observed by the group of Nussenzweig when they compared their new mAbs with results from the original plasma [16] . Some neutralization-sensitive isolates, CA1 (A), MN (B), BaL (B) and CI 13 (D), were added to the panel in table 6. However, there was only a limited increase in range with HJ16 mAb reaching 80% neutralization against CI 13 (D) and HGN194 mAb almost neutralizing BaL (B) to 80%. HK20 mAb had no activity against any of the extra isolates.