Increased Expression of CD169 on Blood Monocytes and Its Regulation by Virus and CD8 T Cells in Macaque Models of HIV Infection and AIDS.

Abstract Increased expression of CD169 on monocytes has been reported in HIV-1-infected humans. Using rhesus macaque models of HIV infection, we sought to investigate whether simian immunodeficiency virus (SIV) infection upregulates CD169 expression on monocytes/macrophages. We also sought to determine whether CD8 T cells and plasma viral load directly impact the expression of CD169 on monocytes during SIV infection. We longitudinally assessed monocyte expression of CD169 during the course of SIV infection by flow cytometry, and examined the expression of CD169 on macrophages by immunohistochemistry in the spleen and lymph nodes of uninfected and infected macaques. CD169 expression on monocytes was substantially upregulated as early as 4 days during the hyperacute phase and peaked by 5–15 days after infection. After a transient decrease following the peak, its expression continued to increase during progression to AIDS. Monocyte CD169 expression was directly associated with plasma viral loads. To determin...