- September | Top publications
- Javier Barrera-Zarate et al.
The porcine epitheliochorial placenta creates a barrier for the transplacental transfer of some nutrients from the dam to the fetus, as well as feto-lethal viruses such as porcine reproductive and respiratory syndrome virus 2 (PRRSV-2). Areolae are specialized structures within the porcine placenta with a high absorptive and substance transport capacity that facilitate embryonic development. The overarching aim of this study was to characterize the localization of PRRSV-2 in and adjacent to areolae to provide insight into whether transplacental transmission might occur through placental areolae. Control (CON) plus three phenotypic fetal groups were selected based on levels of virus in fetal placenta, sera and thymus, to determine if fetal resilience was related to differences in PRRSV-2 localization, alone or co-localized with CD163+ macrophages. These fetal groups represented a range of susceptibility: uninfected (UNINF) being resistant, infected in placenta only (PLCO) being resilient, and high viral load viable (HVL-VIA) being most susceptible. Finally, potential factors related to PRRSV-2 localization, including the severity of inflammation in endometrium and placenta, and intrauterine growth restriction, known resilience factors, were assessed. Thirty-one pregnant gilts were inoculated with PRRSV-2 at gestation day 86 ± 0.4. Seven pregnant gilts were sham-inoculated. Gilts were euthanized at 12 days post-infection. Presence of PRRSV and CD163+ macrophages were determined using immunofluorescence in cryosections of maternal-fetal interface (MFI) with and without areolae. In the maternal, fetal and cavity of areolar region PRRSV particles were found both independently and co-localized with CD163+ macrophages.