IL-4 rescues total CD79b protein expression in CLL cells. (A) U-CLL cells (top) and M-CLL cells (bottom) were cocultured in the presence of IL-4 or the absence (MED) of IL-4 (25 ng/mL) for 48 hours. CD79a and CD79b protein in viable CLL cells was examined by immunoblot. (B-C) Summary of results representing fold change in CD79a and CD79b protein expression, respectively. Lines represent mean ± SEM of 5 samples. Each spot represents an individual sample. (D) CLL samples were NC, or cocultured in the absence (SC) or presence with IL-4 (25 ng/mL) (IL-4 + SC), or cultured with IL-4 (25 ng/mL) (IL-4) alone for 48 hours. CD79b protein in viable CLL cells was examined by immunoblot. (E) CLL samples were cocultured with IL-4 at 0, 5, 10, 25, or 50 ng/mL for 48 hours. CD79b protein in viable CLL cells was examined by immunoblot. (F) CLL samples were cocultured with IL-4 (25 ng/mL) for 0, 24, 48, or 72 hours. CD79b protein in viable CLL cells was examined by immunoblot. (G) CLL samples were cocultured in the absence (MED) or presence of IL-4 (25 ng/mL), IL-21 (25 ng/mL), IL-6 (25 ng/mL), IL-13 (25 ng/mL), IL-1 (25 ng/mL), and CD40L (25 ng/mL) for 48 hours. CD79b protein in viable CLL cells was examined by immunoblot. (H) CLL samples were cocultured in the absence (MED) or presence of IL-4 for 48 hours. CD79b mRNA expression was examined by quantitative PCR. Lines represent mean ± SEM of 5 samples. Each spot represents an individual sample. (I) M-CLL samples were cocultured in the absence (MED) or presence of IL-4 (25 ng/mL), or a combination of IL-4 (25 ng/mL) and CD40L (25 ng/mL) for 48 hours. Results in (A,D-G,I), represent 1 of 5 independent experiments. Membranes were stripped and reprobed with anti-actin antibody as a loading control. ***P < .005; ****P < .001. NC, noncultured; NS, not significant.