Regulatory T cells (Tregs), interleukin 17-producing T helper cells (Th17 cells), and other immune cells play important roles in the maintenance of pregnancy, and their function is impacted by HIV infection. I hypothesized that FIV-infection may likewise alter placental T cell gene expression causing aberrant immune function and compromised pregnancy. The purpose of this project was to evaluate the expression placental immunomodulators related to Treg and Th17 cell function in the FIV-infected cat model. Gene expression was quantified in placenta and serum using quantitative PCR and ELISA, respectively. Abnormal expression of cytokines was frequently associated with infection and fetal nonviability, resulting in discordant relationships between cytokine pairs and the nuclear transcriptional regulators FoxP3 and RORã. The expression of IL-6 in the periphery mirrored that of the placenta, indicating a potential serological means to predict pregnancy outcome. In conclusion, aberrant placental immunomodulation accompanied failed pregnancy in the FIV-infected cat model.