Intravenous titration of SHIV-1157ipd3N4.

aThese animals were first exposed to a 1∶250,000 and 1∶500,000 dilution of the virus. When infection failed to occur after the initial dose, the monkeys were re-exposed to a 1∶25,000 dilution, which proved to be infective.bInfection in these animals peaked at week 3.cThese animals were first exposed to 1∶1,000,000, 1∶1,500,000 and 1∶5,000,000 dilution of the virus. After infection failed to occur, the monkeys were re-exposed to 1∶100,000 and 1∶250,000 dilution of virus, which was infective.Although we initially enrolled 8 RM into the two groups, 1 RM was lost during quarantine due to unrelated causes. The prior i.r. study challenge study also used 8 RM per group [11].