TABLE 3

HIV-1 NAb titers and outcomes of SHIV challenge

Study stageDose (PFU)/routeAnimal no.HIV-1 NAb titeraOutcome of
SHIV-SF162-P4 challenge
Day of boost2 wk postboost4 wk postboost2 wk postchallenge
I5 × 108/sublingualR101061720,69811,924
5 × 108/sublingualR10131<104,4402,883b
II1 × 109/sublingualZ09183<101735c191,743Infected
1 × 109/sublingualL10124268,6332,353c1,033Delayed acquisition
5 × 108/tonsillarR100903113,6599,711c4,103Protected
5 × 108/tonsillarL10141108,4294,476c3,866Protected
  • a Defined as the reciprocal serum dilution that resulted in a 50% reduction of viral infectivity as determined in the TZM-bl cell assay, using HIV-1 SF162 Env-pseudotyped virus as the indicator (see Materials and Methods). HIV-1 pseudotyped with Env from murine leukemia virus (MLV) was used as a control for nonspecific activities. NAb titers (ID50) against MLV-pseudotyped virus were <10 for all serum samples tested. —, animals were not challenged.

  • b Measured at 6 weeks postboosting.

  • c Day of challenge for stage II animals.