TRANSFORMING GROWTH-FACTOR-BETA-1 SERVES AS AN AUTOCRINE INHIBITOR OFHUMAN ENDOTHELIAL-CELL LYMPHOCYTE ADHESION

Other investigators have shown that exogenously administered transform ing growth factor-beta (TGF-beta) inhibits lymphocyte adherence to vas cular endothelial cells (VEC). We examined the role of TGF-beta 1 as a n autocrine mediator of lymphocyte adhesion to adult human VECs. VECs were harvested from eight saphenous or cadaveric iliac veins using 0.2 % collagenase. Low-passage VECs in MCDB + 0.1% BSA were pretreated for 24 hr with monoclonal anti-TGF-beta 1 antibody (5 mu g/ml), LPS (5 mu g/ml), or IL-1 (10 U/ml). Adherence of fluorescently labeled lymphocy tes to pretreated VECs was quantitated and results were expressed as r elative adhesion compared to untreated control. Total mRNA from LPS- o r IL-1-treated VECs was subjected to Northern analysis to determine re lative TGF-beta 1 expression. Total TGF-beta 1 protein concentration i n supernatants from LPS- or IL-1-treated VECs was determined by ELISA. Data (means +/- SEM) were analyzed by ANOVA with a Newman-Keuls postt est. Neutralizing endogenous TGF-beta 1 with anti-TGF-beta 1 antibody significantly increased adhesion of lymphocytes to VEC monolayers comp ared to control (125 +/- 3 vs 101 +/- 2%, P < 0.01, n = 8). The level of adhesion was equivalent to that seen with IL-1 stimulation (131 +/- 6%). Spearman correlation of lymphocyte adherence to IL-1- or LPS-tre ated VECs vs TGF-beta 1 mRNA expression or vs relative TGF-beta 1 prot ein concentration showed significant inverse relationships (r = -0.82, P < 0.001, and r = -0.87, P < 0.001, respectively). Endogenous TGF-be ta 1's inhibitory effect on lymphocyte adhesion was blocked by a speci fic neutralizing antibody. VEC TGF-beta 1 mRNA expression and TGF-beta 1 production were inversely proportional to lymphocyte adhesion, sugg esting down-regulation of TGF-beta 1 in response to proinflammatory cy tokines. Together, these observations support the hypothesis that TGF- beta 1 has an autocrine inhibitory role in regulation of lymphocyte ad hesion to VECs. (C) 1995 Academic Press, Inc.