Furthermore, as the intestine is regionalized into several sections with specific functions [32], and as we found higher infection rate of the small intestine than in the large intestine in SIVmac-infected cynomolgus macaques (Figure B in S1 Text), we analyzed the IP-10 gene expression in 4 distinct sections, i.e. jejunum, ileum, colon and rectum. Here, CXCL10 is linked to infection.