LAUSR

Macaca leonina (northern pig‐tailed macaques, NPMs) have variable disease progression during SIVmac239 infection. In the present study, we analysed, for the first time, the correlations between T‐cell phenotypes and disease progression in NPMs during SIVmac239 infection. In comparison to normal progressors (NPs), slow progressors (SPs) had lower chronic T‐cell activation and exhaustion levels. In addition, SPs showed higher peripheral CD4+ T‐cell count and CD4 : CD8 ratio, and lower plasma viral load than NPs. CD4+ T‐cell count and CD4 : CD8 ratio decreased more sharply in NPs than in SPs. Furthermore, T cells in NPs were more highly differentiated, at least in acute infection, than in SPs. These results indicated that T‐cell phenotypes were correlated with disease progression in SIVmac239‐infected NPMs and these correlations may provide valuable guidance for the improvement of therapeutic strategies tested in NPMs.