A Fast and Reliable Method to Isolate Human Placental Macrophages

Abstract

Macrophages are specialized cells involved in recognition, uptake, and destruction of microorganisms. Human placental macrophages are poorly investigated because of the lack of a convenient protocol for their isolation. Here, we present a straightforward and reliable method to isolate macrophages from full‐term human placentas. After enzymatic digestion of placental tissue and centrifugation of the cell suspension on a Ficoll cushion, placental macrophages are selected using magnetic beads coated with anti‐CD14 antibodies. Isolated cells are characterized by flow cytometry. Ninety eight percent of isolated CD14+ placental macrophages also express the macrophage marker CD68. Thus, this efficient and reliable method yields placental macrophages at high purity and sufficient quantity for functional studies. © 2019 by John Wiley & Sons, Inc.

Full-Term Human Placental Macrophages Eliminate Coxiella burnetii Through an IFN-γ Autocrine Loop

“…Placental macrophages represent 20–30% of the leukocytes found in all compartments of the placenta and their proportion increased throughout pregnancy (Bulmer et al, 2010). The phenotypic characterization of placental macrophages relies on the expression of CD68, a myeloid marker and CD14, a marker of circulating monocytes that is lacking in tissue macrophages other than placental macrophages (Ben Amara et al, 2013; Mezouar et al, 2019a). Placental macrophages include two populations of different origin.…”

Placental macrophages: Origin, heterogeneity, function and role in pregnancy-associated infections

“…The isolation of human macrophages from placenta has appeared as the most convenient approach for macrophage characterization and functional studies. Different methods have been used to isolate placental macrophages [ [15] , [16] , [17] , [18] ]. The location of macrophages in a complex tissue such as placenta and the lack of pertinent animal models make their study particularly challenging.…”

“…Isolating macrophages from human placentas is the most convenient approach for functional studies. Different methods have been used: they vary in the use of enzymes (collagenase, DNase and/or trypsin), density gradient type (Ficoll or Percoll), positive or negative selection using anti-CD68, -CD10 or -CD14 antibodies or adhesive properties [ [15] , [16] , [17] , [18] ]. We have developed a method using Ficoll procedure and anti-CD14 antibodies to isolate human placental macrophages with high purity and yield [ 18 ], but this does not discriminate their fetal/maternal origin.…”

Changing the paradigm of IFN-γ at the interface between innate and adaptive immunity: Macrophage-derived IFN-γ

“…Our studies of placental macrophages strengthened our conviction that the question of macrophage‐derived IFN‐γ had not been fully addressed. Placental macrophages 28 belong to the placental immune system, which also includes NK cells, lymphocytes, DCs, 29 and mast cells 30 . While the population of NK cells decreases throughout pregnancy, the number of macrophages remains pretty stable.…”

“…We recently reported that CD14 + placental macrophages from at term pregnancy released large amounts of IFN‐γ following stimulation by C. burnetii , 17 an intracellular bacterium responsible for Q fever and known for its placenta tropism 57–59 . Using a previously reported method of isolation, we obtained placental macrophage CD14 + /CD68 + with 98% purity 28 . The secretion of IFN‐γ by placental macrophages was sustained during the time of culture with bacteria, suggesting that macrophage‐derived IFN‐γ is present in early and late phases of antibacterial response.…”