Cross-linking of LFA-1 induces secretion of macrophage inflammatory protein (MIP)-1Alpha and MIP-1beta with consequent directed migration of activated lymphocytes.

Abstract: Cross-linking of LFA-1 induces an active locomotory phenotype in T cells. In this study we demonstrate that cross-linking of LFA-1 using a monoclonal antibody results in the secretion of MIP-1alpha and MIP-beta. Similar results were seen with anti-CD44 but not with anti-transferrin receptor or anti-MHC class 1. We examined the ability of activated lymphocytes to migrate onto a substrate consisting of large protein G-Sepharose beads coated with anti-LFA-1 and anti-CD44. In this system a signal is provided by cells at the point of contact with beads. Cells migrated to cover the bead surface within 24h. This contact was shown to be inhibited by the introduction of neutralizing antibodies to MIP-1alpha and MIP-1beta. Hence cross-linking of LFA-1 or CD44 induce chemokine secretion which may be of relevance in directional migration of lymphocytes.