ALT-803 sends SIV-specific CD8⁺T cells to the B-cell follicles. SIV-infected RMs received 100 μg/kg of ALT-803. Lymph nodes were sampled before ALT-803 treatment and 5 days posttreatment. (A-B) Representative images of Mamu-A*01 Gag_181-189CM9-specific tetramer–positive cells (red), CD20⁺ cells (green), and CD8⁺ cells (blue) in lymph node sections taken from SIV-infected animal 31252 (A) before and (B) 5 days after ALT-803 treatment. CD20 staining is used to define B-cell follicles (F) and extrafollicular regions (EF) outside B-cell follicles. The images on the far right show the same field as presented in the middle panel with only the red tetramer staining shown. Each tetramer-binding cell is indicated with a white arrow. In panels A and B, scale bars indicate 100 μm (left panels) and 50 μm (2 enlarged right panels). (C) Numbers of tetramer-positive CD8⁺ T cells per millimeter squared inside and outside of the B-cell follicle as well as total tissue before and after ALT-803 treatment. Animal identification numbers and the MHC-I tetramer used are indicated for both SIV progressors (red solid lines) and controllers (dashed blue lines). (D) F:EF ratio of tetramer-positive CD8⁺ T cells per millimeter squared before and after ALT-803 treatment. (E) F:EF ratio of SIV-producing cells evaluated via RNAscope analysis in lymph nodes of SIV-infected RMs before and after ALT-803 treatment. (C-E) *P < .05; **P < .01; ***P < .001.