Fig. 1.

Plasma viremia and CD4⁺ T cell levels in a rhesus monkey dually infected with X4- and R5-tropic SHIVs. Macaque CE43 was inoculated intravenously with the X4-tropic SHIV_DH12 and the R5-tropic SHIV_AD8. Plasma viral RNA levels were measured using env gene primer pairs specific for each SHIV or gag gene primer pairs able to detect both viruses. The numbers of total circulating CD4⁺ T cells were determined during the 100 weeks of infection by flow cytometry.