Effect of Culture Conditions on the Phenotype of THP‐1 Monocyte Cell Line

Problem Macrophage function has many implications in a variety of diseases. Understanding their biology becomes imperative when trying to elucidate immune cell interactions with their environment, and in vitro cell lines allow researchers to manipulate these interactions. A common cell line used is THP ‐1, a promyeloid cell line suggestive to outside factors, and therefore sensitive to culture conditions. In this study, we describe how culture conditions can alter THP ‐1 morphology and in turn affect their response to differentiation stimuli. Method of Study THP ‐1 cells were cultured in two conditions and treated with phorbol 12‐myristate 13‐acetate ( PMA ) or MCSF . CD 14 surface expression was determined by flow cytometry and cytokine/chemokine production determined by multiplex analysis. Results Culture conditions of THP ‐1 affect their response to PMA . Highly confluent THP ‐1 cells differentiate into a heterogeneous population responsive to PMA as seen by an increase in CD 14 expression. However, these cells, cultured in low confluence, remain as a homogenous population and do not gain CD 14. Additionally, there are major differences in the constitutive cytokine profile. Conclusion We demonstrate that the culture conditions of THP ‐1 cells can alter their response PMA . This suggests that culture techniques may account for the discrepancy in the literature of both basal THP ‐1 phenotype and their response to PMA .