Temporal assessment of the depletion in T-cell receptor excision circles (TREC/CD8⁺) and IL-7 increase in SIVmac239-infected macaques. The longitudinal assessment of TRECs within the CD8⁺ T-cell population (black lines, ▵) with plasma IL-7 levels (gray lines, ▦) are presented for SIVmac239-infected macaques RM1 (A), RM2 (B), RM3 (C), RM4 (D), RM5 (E), and RM6 (F).