Differences between macrophage migration inhibitions by lymphokines and muramyl dipeptide (MDP) or lipopolysaccharide (LPS): Migration enhancement by lymphokines

Abstract

The mode of macrophage migration inhibition by lymphokines or a purified macrophage migration inhibitory factor (MIF) was found to differ from that by muramyl dipeptide (MDP) or lipopolysaccharide (LPS). First, a number of spreading macrophages were observed on the border of an aggregated mass of macrophages, the migration of which was inhibited by lymphokines or MIF, whereas few macrophages were spread in the case of MDP or LPS. Second, macrophage migration enhancement occurred at Day 3 in the case of lymphokines or MIF, whereas neither MDP nor LPS caused such an enhancement. These results suggest that macrophage activation by MIF differs from that by MDP or LPS. Also, the enhancement of macrophage migration by MIF at Day 3 is a hitherto unreported property of MIF.