Figure 1

Effect of cM-T807 administration on CD8⁺ T cells of African green monkeys. a. As shown by flow cytometry analysis, the CD8-depleting antibody induced complete depletion in peripheral blood for 14-21 days. Both percentage (upper left panel) and absolute (upper right panel) CD8⁺ T cell counts are shown. In the LN, the depletion, although complete was shorter than in periphery (lower left panel), while in the intestine, only a transient, incomplete depletion was observed (lower right panel). Red symbols and lines denote CD8-depleted monkeys. Black symbols and lines denote the control monkeys. b. Flow-cytometry plots of CD4⁺ and CD8⁺ populations (gated on CD3⁺) in peripheral blood, lymph nodes and intestine demonstrate that administration of CD8-depleting mAb determined depletion in periphery and lymphoid tissue and likely induced down regulation/blocking of CD8 molecule rather than CD8⁺ cell depletion in the intestine. Thus, in monkeys treated with cM-T807 mAb (lower panels), downregulation of CD8 cells in the gut is suggested by the massive increase in the double negative population at the time of maximum depletion (day 8 p.i.) compared to baseline (day 0 p.i.). With the rebound of CD8⁺ cells, this double negative population vanishes, as illustrated here by a plot on samples collected at day 28 p.i.