Comparative characterization of cultures of primary human macrophages or dendritic cells relevant to biomaterial...

Macrophages are central mediators of biomaterial-associated wound healing. Dendritic cells (DCs) link innate and adaptive immunity and are important in the context of the host response to combination products. Starting with human peripheral blood mononuclear cells (PBMCs), DCs were derived from monocytes upon culture with granulocyte macrophage colony-stimulating factor and interleukin-4; macrophages were derived from monocytes upon culture without cytokines. Macrophage or DC cultures were characterized at relevant timepoints in both adherent and nonadherent fractions on control Primaria surfaces to characterize and define these inflammatory/immune cells as a prequel to their use in in vitro test biomaterial-host response studies. At day 10 (typical time for harvesting macrophages for subsequent treatment with test biomaterials), macrophages were CD11c+, macrophage mannose receptor (MMR)+, CD14+, and CD64+. At day 6 (typical time for harvesting of DCs after 24-h treatment with test biomaterials), DCs were CD1c+, CD11c+, CD123+, MMR+, CD14+, and CD64-. Furthermore, CD3+ and CD4+ T lymphocytes and CD19+ and CD24+ B lymphocytes were present in both cultures at all timepoints, although to different extents. Immature DCs (approximately 15 microm), were rounded but presented extensive dendritic processes upon maturation with lipopolysaccharide. Alternatively, adherent macrophages (approximately 15-20 microm) displayed internalized lipids and exhibited few membrane processes. The characterization and comparison of existing techniques to establish reliable, reproducible primary cultures of DCs or macrophages provides an important basis for examining and interpreting complex macrophage/DC-lymphocyte-orchestrated host responses in future studies with equivalent cell populations on test biomaterials.