CD44 variant–specific antibodies induce bone marrow–derived macrophages to secrete GM-CSF and IL-6.

Macrophages were stimulated with different amounts of CD44 v4 and CD44 v6 antibodies. Conditioned media from macrophage cultures (4 cultures) treated for 48 hours with CD44 variant–specific antibodies at concentrations indicated were tested by ELISA for the production of GM-CSF (A) or IL-6 (B). (C) Bone marrow–derived macrophage cultures (4 cultures) were treated with CD44 variant antibodies (10 μg/mL) together with a peptide covering the epitope recognized by the CD44 v6-specific antibody (AATQQETWFQNGWQ; kindly provided by Benda and Co, Vienna; concentration 10 μg/mL), and the concentration of GM-CSF was determined in the conditioned medium. The experiments described in A and B were repeated 4 times, and the experiment in C was done twice. In each case, similar results were obtained in the replicate experiments.