Hi,

I recently began working with THP-1 cells from ATCC and have followed the manufacturer's protocol, incorporating 2-mercaptoethanol and 10% heat-inactivated FBS. I am using RPMI from Thermo (not the ATCC version, Catalog number A1049101).

After three days of thawing the cells, their morphology appeared consistent with the ATCC guidelines (Fig 1). However, I noticed a change in phenotype, with the cells starting to adhere to the 75-flask.

I split the cells in suspension to a 6 well plate to allow a faster growing (also added a new media to the first flask to follow up the behavior). The cells in the flask have begun to elongate and firmly adhere to the bottom (Fig 2), while those in the 6-well plate are also attaching but remain in suspension, but showing a slow growth (Fig 3).

There is any suggestions for achieving a more optimal THP-1 expansion culture that I can subsequently differentiate to M0 using PMA? Thank you!