Fig. 4.

Constitutive IL-6 production and its modulation by cytokines. 5 × 10⁴ of T-HPMC (a, c) and P-HPMC (b, d) were incubated at 37°C for 24 h in CM alone or in medium contain different doses of hIL-1β (a, b) and hTNF-α (c, d). The results were representatives of three similar experiments of two T-HPMC lines and two P-HPMC cultures, and were expressed as mean ± s.d. tested in quadruplicate. Doses of hIL-1β≥ 0·1 ng/ml (T-HPMC) and 0·01 ng/ml (P-HPMC), hTNF-α≥ 10 U/ml (T-HPMC) and 100 U/ml (P-HPMC) resulted in significantly increased IL-6 release compared to control medium. * P <0·05, ** P = 0·001, *** P <0·001.