s / Placenta 35 (2014) A1eA112 A64 activitywas abolishedwhenHCMVparticleswas treated beforehand by the PLA2 inhibitor methyl arachidonyl fluorophosphonate (MAFP). We next showed that in HCMV-infected trophoblasts, MAFP treatment abrogated: i) induction of immediate early gene expression; ii) apparition of neutral lipid droplets, a marker of PPARg activation, as assayed by Oil Red O staining; iii) inhibition of cytotrophoblast migration as assayed by wound healing. To screen potential PPARg ligands among PLA2 metabolites, we set up a new method based on solid phase extraction coupled with HPLC and tandem mass spectrometry analysis (LC-2MS). LC-2MS revealed that secretion of 13-HODE, a linoleic acid metabolite, was significantly increased in infected HIPEC and explants, whereas no significant change was detected in the levels of arachidonic acid metabolites. This effect was abolishedwhen HCMVwas treated byMAFP. Finally, treatment of HIPEC by synthetic 13-HODE induced lipid droplets accumulation and reduced cell migration in a dose dependent manner. Conclusion: Our findings disclose that 13-HODE is a major PPARg ligand produced in cytotrophoblasts upon infection by HCMV via onboarded PLA2 activity. P2.8. PLACENTAL INFECTION BY SALMONELLA ENTERICA TYPHIMURIUM IN A MURINE MODEL: MECHANISMS OF PATHOGENESIS AND ROLE OF INFLAMMATORY CELL DEATH Kristina Wachholz , Gerard Agbayani , Tina Nguyen , Komal Gurnani , Lakshmi Krishnan a,b University of Ottawa, Ottawa, Ontario, Canada,; National Research Council of Canada, Ottawa, Ontario, Canada Objective: Pregnancy confers increased susceptibility to intracellular infections such as Salmonella enterica serovar Typhimurium (S. Tm). S. Tm infection during pregnancy in normally resistant mice (129X1/SvJ with a fully functional Nramp gene) leads to rapid severe placental inflammation followed by fetal andmaternal death. However, the immunemechanism of feto-maternal interface inflammation has not been fully elucidated. The objective of this study was to test the hypothesis that the mechanism of trophoblast (TBC) cell death following infection, contributes to fetomaternal inflammation and adverse effects on the mother and fetus. Methods: Mice, wild-type (B6.Nramp+/+) and gene-deficient strains (Ifnar1-/-, Rip3-/-, Caspase1/11-/-) were infected with S. Tm by the intravenous or oral route in the non-pregnant state or during mid-pregnancy (day 11-12). The bacterial burden in the organs (spleen, liver, placenta, lymph nodes) was enumerated 24-72 h post-infection. Immunophenotyping by flow cytometry was carried out for the placental and splenic lymphocytes 48 h post infection. Results: Infection of S.Tm (low dose, 103) by the systemic route resulted in preferable replication of the bacteria in placenta, and fetal resorptions in the B6.Nramp+/+ mice corroborating previously published studies in the 129X1Sv/J mice. Additionally, oral infection of S. Tm (108) resulted in systemic dissemination of the bacteria to the placenta by 5 days postinfection and pathogen replication leading to adverse pregnancy effects. Infiltration of neutrophils and other innate immune inflammatory cell types to the placenta occurred within 48 h post-infection. Gene-deficient mice strains demonstrated differential susceptibility to S. Tm infection suggesting modulation of specific immune and cell death pathways contributed to placental S.Tm infection. Conclusion: Oral S. Tm infection may pose a serious threat of placental infection during pregnancy. Collectively our studies suggest that placental cell death and immune deviation at the feto-maternal interface may contribute to the pathogenicity of food-borne infections during pregnancy. P2.9. HOW THE PLACENTA MAKES PREGNANT WOMEN VULNERABLE TO INFLUENZA (FLU) Jorge M. Tolosa , Kristy Parsons , Peter Wark , Roger Smith a Mothers and Babies Research Centre. The University of Newcastle and Hunter Medical Research Institute (HMRI), Newcastle, NSW, Australia; Respiratory Medicine. The University of Newcastle and Hunter Medical Research Institute (HMRI), Newcastle, NSW, Australia Introduction: Influenza remains one of the most important transmissible viral infections worldwide, causing a significant annual burden of illness. Pregnantwomen are particularly susceptible to influenza, with an increased risk of severe respiratory disease and death, despite modern medical care. Pregnant women infected with 2009 pandemic influenza A (H1N1) were disproportionately over-represented among hospitalizations, ICU admissions, and deaths (50% of the pregnant women infected worldwide were hospitalized, of whom 23% were admitted to an ICU and 8% died). The reason for this enhanced susceptibility however remains unclear. Recent investigations have shown that the placenta produces and secretes immunosuppressive retroviral envelope proteins and immunomodulating exosomes that may explain the inhibition of innate and adaptive cellmediated immune responses characteristic of pregnancy. Hypothesis: Therefore, to explain the susceptibility of pregnant women to influenza, we hypothesized that the human endogenous retroviral envelope protein syncytin-1 and human placental exosomes suppress maternal innate and adaptive cell mediated immune responses to influenza viruses by altering the function of peripheral blood mononuclear cells (PBMCs). Methods: We produced and purified recombinant syncytin-1 ectodomain. We then exposed PBMCs from non-vaccinated pregnant (n1⁄410) and nonpregnant women (n1⁄410) to H1N1pdm09 and H3N2, with and without exposure to syncytin-1. Cell types were identified by flow cytometry, while cytokine release was assessed by bead array and ELISA. Results: In PBMCs exposed to influenza virus, syncytin-1 reduced the release of IFN-alpha and IFN-Lambda1 from pDCs and NK cells. In regard to T cell responses, syncytin-1 pretreatment led to reduced release of IFNgamma, but heightened activation of TRegs, with increased release of IL-10 and increased TReg expression of CTLA-4 and GITR. Conclusion: The release by the placenta of syncytin-1 in exosomes into the maternal bloodstream may explain the decreased cell-mediated immune responses observed during pregnancy and the severe course of influenza during pregnancy. P2.10. IDENTIFICATION OF THE PLACENTAL INFLAMMATORY CYTOKINE TRANSCRIPTIONAL SIGNATURE ASSOCIATED WITH CONGENITAL CMV INFECTION Mark Schleiss, Peter Gillis University of Minnesota Medical School, Division of Pediatric Infectious Diseases, Minneapolis, MN, USA Objectives: In the USA and Europe annually, ~60,000 infants are bornwith congenital cytomegalovirus (CMV) infection, and over 8,000 will sustain long-term disabilities. Although perturbations in placental cytokine expression have been identified in a variety of maternal disease states associated with adverse fetal outcomes, the placental immunologic correlates associated with congenital CMV transmission remain poorly defined. Methods: To address this knowledge gap, we compared cytokine gene expression in placentas from pups that acquired congenital CMV infection, versus placentas from non-transmitting mother-infant dyads, using a guinea pig model. Six mid-gestation female Hartley guinea pigs were challenged subcutaneously with 5 x 104 pfu of salivary gland passaged guinea pig CMV. Animals were euthanized at 21 days postinfection (dpi) and placentas and pups were matched and collected. Congenital CMV infection was identified by real-time PCR analysis of pup tissues (brain, lung and liver). A novel, guinea pig-specific Luminex assay was developed to compare expression of multiple placental cytokine mRNAs. Results: Five cytokines (TNFa, IL-6, IL-15, RANTES, and IL-1b) were significantly increased in placentas from CMV-infected pups (n1⁄45), compared to uninfected pups (n1⁄46; p<0.02 Mann-Whitney; Figure). In contrast, maternal blood cytokine mRNA expression (determined from samples obtained at 3, 7, 14, and 21 dpi) was identical when transmitting Abstracts / Placenta 35 (2014) A1eA112 A65s / Placenta 35 (2014) A1eA112 A65 and non-transmitting dams were compared. However, significant increases in TNFa protein (p < 0.05, t-test) were observed by ELISA in serum of CMV-transmitting dams (n1⁄43) at 21 dpi (mean 980 pg/ml), compared to non-transmitters (n1⁄43; <10 pg/ml). Conclusion: This study demonstrates that congenital CMV infection is associated with a signature inflammatory cytokine mRNA profile in the placenta, and elevated levels of TNFa in maternal blood. Elucidation of this cytokine “fingerprint” provides biomarkers for identifying pregnancies at risk for maternal-fetal CMV infection, and could be useful in tracking responses to potential therapies and for investigating pathogenesis.