The frequencies (within the total CD4+ T-cell population) of intestinal IL-17+IFN-γ+ cells significantly decreased upon SIV infection (day 58 p.i.)as compared to pre-infection (day -20 p.i: 3.303 ± 0.3027; day 58 p.i: 1.088 ± 0.3906; mean ± S.E; p = 0.0017), and were significantly increased with ART treatment (day 256 p.i; 1.979 ± 0.7622; mean ± S.E) as compared to day 58 p.i. (p = 0.0156; S6 Fig). The gene discussed is IL17A; the disease is infection.