Effect of chronic morphine administration on circulating dendritic cells in SIV-infected rhesus macaques

- SIV infection alters the number of circulating mDCs and pDCs in rhesus macaques.
- Chronic morphine administration attenuates the SIV-induced increase in the number of circulating mDCs.
- Chronic morphine administration up-regulates the number of circulating pDCs following SIV infection.
- Chronic morphine transiently increases the number of circulating pDCs in the absence of SIV infection.

We studied the effect of chronic morphine administration on the circulating dendritic cell population dynamics associated with SIV infection using rhesus macaques. Animals were either first infected with SIV and then given chronic morphine, or visa versa. SIV infection increased the numbers of myeloid DCs (mDCs), but morphine treatment attenuated this mDC expansion. In contrast, morphine increased the numbers of plasmacytoid DCs (pDCs) in SIV-infected animals. Finally, chronic morphine administration (no SIV) transiently increased the numbers of circulating pDCs. These results show that chronic morphine induces a significant alteration in the available circulating levels of critical antigen-presenting cells.

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