A transwell assay was used to investigate the recruitment ability of macrophages and trophoblasts. The idea is that cells plated in the lower well releases chemotactic cytokines, called chemokines, which can recruit other cells.
Which cells that are recruited depends on what kind of chemokines the cells plated in the lower releases.

Peripheral blood mononuclear cells (PBMC) placed in the transwell inserts migrated through a Matrigel coated membrane, if recruited by the in vitro differentiated macrophages or the trophoblasts cell line plated in the lower wells (Figure 1).

Flow cytometry was used to analyse number of migrated cells and cell types.