FIG. 1.

Longitudinal follow-up of virus loads in plasma and PBMC and CD4⁺ T-cell counts in SHIV-SF162P3 titration animals. (Left panels) Intravenous titration of SHIV-SF162P3 in juvenile M. nemestrina macaques. Groups of two juvenile macaques were exposed to 10-fold-decreasing concentrations of challenge stock, with the highest dose of 10.0 TCID₅₀ being the undiluted challenge stock. (Right panels) Oral titration of SHIV-SF162P3 in newborn M. nemestrina macaques. Groups of two newborn macaques were exposed to increasing concentrations of challenge stock, with the lowest dose of 10.0 TCID₅₀ being the undiluted challenge stock. Newborns exposed to 20.0 and 30.0 TCID₅₀ were exposed twice and three times, respectively, at 1-hour intervals to 1 ml of undiluted virus stock. Plasma virus loads in juveniles were monitored by real-time quantitative RNA PCR. PBMC DNA virus loads in juveniles and newborns were estimated by real-time DNA PCR. The limits of detection of real-time RNA and DNA PCRs were 100 copies/ml plasma and 3 copies/μg DNA, respectively. The solid lines in the CD4⁺ T-cell graphs indicate a CD4⁺ T-cell count of 250, the level below which AIDS is reported to occur. A dagger indicates death of the macaque due to AIDS.