Journal of Clinical and Cellular Immunology
Open Access

Abstract

Immortalized Murine Macrophage Cell Line as a Model for Macrophage Polarization into Classically Activated M(IFNγ+LPS) or Alternatively Activated M(IL-4) Macrophages

Andra Banete, Paulina Achita, Katherine Harding, Rylend Mulder and Sameh Basta

Objective: Macrophages (Mϕ) represent a link between the innate and adaptive arms of the immune system. Generally, Mϕ are classified into two major subsets after stimulation; either ascribed classically (M1), or more specifically M(IFNγ+LPS) based on the activating condition, or alternatively (M2), or more specifically M(IL-4) activated cells. The purpose of the study was to evaluate an immortalized murine Mϕ cell line (BMA) as an in vitro model for Mϕ polarization into M(IFNγ+LPS) and M(IL-4) phenotypes to facilitate the progress in this exciting research field.

Methods: The BMA cell line was stimulated with either IFNγ and LPS or IL-4 to induce cellular polarization. The cells were characterized using multi-parameter analyses employing phenotypic and functional assays, and compared to bone-marrow derived macrophages (BMDM).

Results: The BMA cell line was found to differentiate into either M(IFNγ+LPS) Mϕ, characterized by production of inflammatory cytokines and up-regulation of inducible nitric oxide synthase (iNOS) or M(IL-4) cells with high Arginase-1 activity. Furthermore, polarized BMA cells were found to have a differential expression of cell surface markers.

Conclusion: These findings demonstrate that the BMA cell line can be polarized into M(IFNγ+LPS)/M(IL-4) phenotypes, and can therefore be used as a model for in vitro Mϕ polarization reducing the need for primary Mϕ isolation when investigating biological phenomena related to their polarization.