Table 2.

Neutralization of HIV-1 isolates on MT2 cells following passage in PBMC and T-cell lines

MAbs, sCD4, and seraNeutralizing antibody titer of indicated isolate toa:
M2424/4W61D
PBMC(p0)H9(p1)H9(p3)H9(p9)PBMC(p3)PBMC(p5)PBMCSupT1
R5X4NDNDR5X4NDR5X4R5X4R5X4
MAbs and sCD4
 2F5100>1001002512.525>503.125
 2G12>100502512.51005012.56.25
 447-52D50253.1251.563.1256.25>250.195
 sCD41051.250.6251.255NDND
 IgG1b12NDNDNDNDNDND>506.25
HIV-1 positive sera
 05216016016016080160320320
 1342040801608080NDND
 FDA#220204080404010320
Vaccinee sera
F55134 104080
F53860 101040
F53863 1080
M54662 102080
F53866 102080
  • a PBMC(p0) represents the primary HIV-1 isolate of M2424/4; H9(p1), H9(p3), and H9(p9) are the viral stocks obtained following the stated number of passages in H9 cells; PBMC(p3) and PBMC(p5) are virus stocks obtained following three or five passages of the H9(p9) stock in PBMC. The W61D virus stocks were obtained from PBMC or following multiple passages in SupT1 cells. Neutralization titers are shown as the reciprocal of the highest dilution of sera or the lowest concentration of MAb or sCD4 to inhibit the formation of syncytia in MT2 cells by 90%, and where no neutralization was observed with the highest concentration of MAb used, this is shown by >. R5X4 represents the ability to replicate in both U87-CD4-CCR5 and U87-CD4-CXCR4 cells. ND, Not done. —, neutralizing titer of <10.