Laminin and fibronectin promote the chemotaxis of human malignant plasma cell lines

Abstract

We examined chemotaxis of human plasma cells (PCs) in response to extracellular matrix proteins (ECMs) in the human PC cell lines FR4ds and OPM-1ds. The FR4ds cells expressed β1+, β3-, α2-, α3-, α4+, α5+, α6+, and αv+ integrins, whereas the OPM-1ds cells expressed β1+, β3- , α2-, α3+, α4+, α5-, α6+, and αv+. Fibronectin (FN) and laminin (LN) promoted the chemotaxis of the PCs. An inhibitory assay with anti- integrin monoclonal antibodies (MoAbs) showed that anti-α4 MoAb partially inhibited the chemotaxis of FR4ds end completely inhibited the chemotaxis of OPM-1ds. Anti-α5 MoAb alone had no effect on either of these two lines. Nevertheless, anti-α5 MoAb completely inhibited chemotaxis when it was added with anti-α4 in FR4ds, demonstrating a novel complementary role of VLA-5 toward VLA-4 in the chemotaxis induced by FN. LN facilitated chemotaxis both in OPM-1ds expressing α3 and α6 integrins and in FR4ds expressing α6 integrin alone. Anti-α6 MoAb completely inhibited FR4ds chemotaxis, whereas anti-α3 and -α6 MoAb had synergistic inhibitory effects on the chemotaxis of OPM-1ds. These results indicated that the distribution of PCs in human tissue are determined by at least two factors: the concentration of the ECM proteins FN and LN and the expression of integrins.