CD4 and HIV infectious disease: Finally, Ontak administration to SIVsab-infected RMs, a model of spontaneous complete control of HIV infection (195, 196), resulted in the depletion of 75–85% of the peripheral Tregs, an 8- to 10-fold increase in immune activation of the peripheral CD4+ and CD8+ T cells and a boost of SIV-specific T cells (168).