Prothymosin alpha1 antagonizes the inhibitory effects of transforming growth factor-beta1 on the adhesion of peripheral blood lymphocytes to human umbilical vein endothelial cells.

Abstract

We investigated the in vitro effects of both prothymosin alpha1 (Pro alpha1) and transforming growth factor-beta1 (TGF-beta1) on the adhesion of peripheral blood lymphocytes (PBL) and on the expression of the adhesion molecules, endothelial-leukocyte adhesion molecule-1 (ELAM-1), intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on human umbilical vein endothelial cells (HUVECs). TGF-beta1 moderately but significantly decreased PBL-binding to interleukin-1 (IL-1)- stimulated HUVECs. However, Pro alpha1 in combination with TGF-beta1 completely restored the TGF-beta1 mediated effects. Other thymic peptides tested were ineffective. On HUVECs, TGF-beta1 diminished ICAM-1 and VCAM-1 expression, leaving ELAM-1 unchanged. Pro alpha1 in combination with TGF-beta1 showed no significant effects on ELAM-1 expression, but antagonized the TGF-beta1-induced decrease of ICAM-1 and VCAM-1 expression on activated HUVECs.