IL-4-INDUCED B-CELL MIGRATION INVOLVES TRANSIENT INTERACTIONS BETWEENBETA-1 INTEGRINS AND EXTRACELLULAR-MATRIX COMPONENTS

IL-4 has previously been shown to stimulate motile responses in murine a lymphocytes. This was studied as acquisition of motile morphology a nd migration through filters in microchemotaxis chambers. In this pape r, we investigated IL-4-stimulated migration of a cells into gels of n ative collagen fibers, which may be a more physiologically relevant as say. When IL-4 was present in the gel and/or in the medium above, a ce lls were able to invade the collagen gel. Migration was dependent on t he dose of IL-4 and was optimal after 45 h of incubation. It appeared that IL-4 acted by inducing both chemokinesis and chemotaxis. Fibronec tin (FN) was found to be an important factor for a cell locomotion, si nce low concentrations of FCS or FN in the gel matrix greatly improved migration. a cell locomotion was inhibited by antibodies specific for beta 1, alpha 4 and alpha 5 integrins, indicating the presence of int egrin-extracellular matrix (ECM) interactions in lymphocyte motility r esponses. Migration was not associated with an up-regulation of beta 1 , alpha 4 or alpha 5 integrins. The adhesion between substrate and cel ls is likely to be of low affinity, since IL-4-stimulated, as well as non-stimulated a cells, did not adhere to ECM-coated culture wells. Ou r data suggest that transient interactions between integrins and the E CM matrix may favour a cell migration.