Fig 4.

CD4⁺ T lymphocyte subpopulations in the gastrointestinal tract of SIV-infected AGMs. The gastrointestinal T lymphocyte population of SIV-infected AGMs comprises low levels of CD4⁺ T lymphocytes (colon median, 2.7%, and range, 1.6 to 24.4%; duodenum median, 2.7%, and range, 0.9 to 30.9%), a substantial proportion of DN T lymphocytes (colon median, 14.8%, and range, 3.2 to 44.4%; duodenum median, 18.9, and range, 4.4 to 46.2%), and a large proportion of CD8⁺ T lymphocytes (colon median, 75.5%, and range, 49.1 to 94.8%; duodenum median, 78.7%, and range, 35.4 to 92.9%) (A). The CD4⁺ T lymphocyte population in the colon and the duodenum of SIV-infected AGMs is mainly the transitional memory (TM) phenotype (CD95⁺ CD28⁺ CCR7⁻: colon median, 73%, and range, 42.4 to 89.8%; duodenum median, 71.3%, and range, 61.9 to 94.6%), with lower proportions of naive (N) (CD95⁻ CD28⁺: colon median, 15.5%, and range, 7.4 to 57.4%; duodenum median, 15.9%, and range, 1.8 to 37.5%) and central memory (CM) (CD95⁺ CD28⁺ CCR7⁺: colon median, 1.3%, and range, 0 to 15.2%; duodenum median, 4.4%, and range, 0 to 20.1%) CD4⁺ T lymphocytes and an extremely low proportion of effector memory (EM) (CD95⁺ CD28⁻: colon median, 0.2%, and range, 0 to 1.3%; duodenum median, 0.4%, and range, 0 to 2.9%) CD4⁺ T lymphocytes (B). Horizontal lines indicate medians.