Immune Profiling of BALB/C and C57BL/6 Mice Reveals a Correlation Between Ureaplasma parvum-Induced Fetal Inflammatory Response Syndrome-Like Pathology and Increased Placental Expression of TLR2 and CD14

Problem Both BALB/c and C57BL/6 mice are susceptible to intrauterine infection with Ureaplasma parvum, but only protypical TH2/M2 BALB/c mice develop severe chorioamnionitis, fetal infection, and fetal inflammatory response syndrome-like (FIRS) pathology. Method of studyMicroscopy, gene expression analysis, and ELISA were used to identify placental innate immune responses relevant to macrophage polarity, severe chorioamnionitis, and fetal infection. ResultsBoth mouse strains exhibited a pro-M2 cytokine profile at the maternal/fetal interface. In BALB/c mice, expression of CD14 and TLRs 1, 2, 6 was increased in infected placentas; TLR2 and CD14 were localized to neutrophils. Increased TLR2/CD14 was also observed in BALB/c syncytiotrophoblasts in tissues with pathological evidence of FIRS. In contrast, expression in C57BL/6 placentas was either unchanged or down-regulated. ConclusionOur findings show a link between increased syncytiotrophoblast expression of CD14/TLR2 and FIRS-like pathology in BALB/c mice. Functional studies are required to determine if CD14 is contributing to fetal morbidity during chorioamnionitis.