To investigate the expression of CD147 both on cellular membrane and in culture supernatant of in vitro cultured THP-1 cells and monocytes of RA patients before and after stimulation with phorbol myristate acetate (PMA).
Human peripheral blood monocytes (HPBMs) were segregated from RA patients by adherent culture method. After the HPBMs and THP-1 cells were stimulated with PMA, the expression rate and expression intensity of CD147 on THP-1 cells and HPBMs of RA patients were determined by flow cytometry. The soluble CD147 levels in culture supernatant of in vitro cultured THP-1 cells and HPBMs were quantified by double antibody Sandwich ELISA.
The soluble CD147 in the supernatant of cultured THP-1 cells and HPBMs was detectable before PMA stimulation. Both cells showed high CD147 expression. After PMA stimulation, soluble CD147 level in the supernatant of THP-1 cells increased. CD147 expression on THP-1 cells firstly increased then decreased and kept stable for several days. CD147 expression on HPBMs of RA patients decreased, but CD147 level in the culture supernatant of HPBMs of RA patients increased and kept stable for 2 days.
CD147 molecule can be shed from the membrane of THP-1 cells and HPBMs of RA patients, or it can be directly secreted into the culture supernatant from the two kinds of cells. PMA can up-regulate the level of soluble CD147.