Cytokine Dysregulation in Early- and Late-Term Placentas from Feline Immunodeficiency Virus (FIV)-Infected Cats

Problem Experimental infection of cats with FIV-B-2542 produces high rates of fetal infection and reproductive failure. We hypothesized that dysregulation of placental cytokine expression occurs in FIV-infected queens, and aberrant expression potentiates inflammation and impacts pregnancy outcome. Our purpose was to quantify expression of representative pro-inflammatory cytokines (IL-6, IL-12p35, and IL-1 beta), IL-10 (anti-inflammatory), and the chemokine SDF-1 alpha in early- and late-term placental tissues. Method of study Real-time reverse transcriptase PCR was used to measure gene expression in placental tissues. Results Increased expression of IL-6 and IL-12p35 and decreased expression of IL-10 occurred in FIV-infected tissues at early pregnancy; at late gestation, IL-6 expression increased and IL-1 beta and SDF-1 alpha decreased. At late pregnancy, IL-6 expression positively correlated with FIV load. IL-12:IL-10 ratios were higher in infected tissues at early, but not late pregnancy. Fetal non-viability accompanied decreased IL-12p35 and SDF-1 alpha expression at both stages and decreased IL-12:IL-10 ratio at late pregnancy. Conclusion FIV infection caused a pro-inflammatory placental microenvironment at early, but not late pregnancy.