Protection of CD4⁺ T cells and reduced viremia in SHIV-infected macaques previously engrafted with mC46-expressing HSCs. (A) Absolute number of CD4⁺CD3⁺ T cells/μl peripheral blood of SHIV-infected macaques engrafted with control (squares and diamonds) or mC46-expressing (circles and triangles) CD34⁺ HSCs, as determined by FACS analysis. The lower limit of the normal CD4⁺ T-cell range is indicated by the dotted line. (B) Levels of SHIV RNA detected in peripheral blood of macaques previously engrafted with control (squares) or mC46-expressing (circles) CD34⁺ HSCs. Macaques were challenged with a viral dose equivalent to 10–50 TCID50. The limit of quantification of the viral load real-time polymerase chain reaction assay was 10² viral RNA copies/mL.