Interleukin-4 induces in vitro migration in naive B cells through direct mechanisms

Interleukin-4 (IL-4) mediated locomotor responses by murine B cells in vitro were examined in this paper. The IL-4 induced migration was found to act directly on purified, splenic B cells, without involvement of secondary mediators. It appeared that only a subpopulation of B cells was able to respond in migration assays. Flowcytometric analysis showed that the migrating cells had the characteristics of naive B cells: I-Alo, J11dhi, IgDhi. They also displayed high expression of the adhesion molecule L-selectin and made predominantly IgM antibodies. This is contrary to what has previously been observed regarding motile responses to chemotactic factors by T cells, which mostly affect memory or activated T cells. However, this is in accordance with other studies indicating that IL-4 is a cytokine that exerts its effect mainly on resting B cells.