Anti-IgM–mediated outcomes in B cells from healthy donors. Comparison of efficacy of HB57-dex and goat anti-μ F(ab′)2 in eliciting protein phosphorylation of Akt, Erk, and p38 MAPK, in B cells from 6 elderly healthy donors. In each case, goat anti-μ elicited a stronger response. Differences were statistically significant as marked (A). Flow cytometric analysis of percentage of hTERT+ cells and density of hTERT expression in activated cells. B cells were cultured in the absence or presence of HB57-dex or goat anti-μ for 3 days. Comparison of fold change in percentage of hTERT+ cells indicates a higher positivity in CD5+ cells in 5 of 5 cases studied (B top panel). Each colored line connecting cell fractions indicates a single donor. Both anti-IgM agents elicited comparable changes in density of hTERT (B bottom panel). (C) Comparable induction of telomerase activity by both anti-IgM agents. (D) HB57-dex induced a significantly higher proliferative response in each of the 6 donors studied. (E) HB57-dex rescued cells from apoptosis, whereas goat anti-μ F(ab′)2 induced apoptosis in all cases studied (P < .001).
