Fig 2.

Schematic representation of different compartments of the placenta colonized with SARS-CoV-2. The placenta comprises different types of cells that form a strong physiological and immune barrier around the fetus. The outer trophoblast layer is a physical barrier divided into 2 layers: the inner cytotrophoblasts (purple) lining the basement membrane and outer multi nucleated (blue color lined with black solid line) syncytiotrophoblasts (STBs). The decidua is the maternal part containing blood vessels and different types of cells such as mesenchymal stem cells and decidual natural killer cells (dNKs). The intervillous space is filled with maternal blood. Based upon multiple studies, SARS-CoV-2 was shown to colonize mainly in STBs, extravillous trophoblasts (EVTs), cytotrophoblasts maternal decidua and fetal macrophages (Hofbauer cells). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)