Lotus tetragonolobus fucolectin as a potential model for “MIF-like” modulation of macrophage function: Comparison of the interaction of Lotus fucose binding protein (FBP) and migration inhibitory factor (MIF) with macrophages in the migration inhibition assay

Abstract

Fucose binding protein (FBP), the fucolectin from Lotus tetragonolobus, was compared with migration inhibitory factor (MIF) for its binding interactions with peritoneal macrophages in the migration inhibition assay and with concanavalin A (Con A) for its mitogenic properties for lymphocytes. FBP was nonmitogenic for guinea pig lymphocytes as demonstrated by its inability to stimulate incorporation of [ 3H]thymidine into TCA insoluble fractions or to induce production of MIF. FBP and MIF inhibited migration of responsive peritoneal macrophages in similar dose-response profiles, whereas refractory macrophages were significantly less responsive to both inhibitors. FBP and MIF were adsorbed correspondingly by responsive macrophages but not by refractory macrophage populations. FBP was bound to peritoneal macrophages during short-term pulse exposure to inhibit macrophage migration in a dose-response fashion similar to that of MIF. Enzymatic treatment of peritoneal macrophages with trypsin, chymotrypsin, or Pronase abrogated their response to both FBP and MIF. l-Fucose (0.1 M) significantly reduced FBP and MIF-mediated migration inhibition while d-fucose and l-rhamnose were ineffective. FBP was also found to augment MIF inhibition of macrophage migration under a variety of experimental conditions. Based on these findings, it is proposed that Lotus fucolectin may provide a useful model for studies on “MIF-like” modulation of macrophage function.