Fig. 2: M2T-CD33 induces a polyclonal humoral response and has anti-tumor efficacy in an in vivo prophylactic model.

A Flow cytometry of CD33 expression on C1498-hCD33 cells prior to injection. Representative survival of the model on right. B ELISA of anti-CD33 IgG over time after injection with M2T-CD33 or controls. Proteins were injected at a dose of 5 µg per mouse as indicated by triangles. C, D Mice were injected with 5 µg M2T-CD33 or controls as indicated by triangles and then challenged 1 week later with 0.5 × 10⁶ C1498-hCD33 cells (Day 0; N = 10). C ELISA of anti-CD33 IgG 1 week after third M2T-CD33 dose. Error bars represent standard error of the mean (SEM). Significance determined by Kruskal-Wallis test and Dunn’s multiple comparisons test, ****P < 0.0001. D Kaplan-Meier survival curves. Significance was determined by log-rank Mantel-Cox test, compared to vehicle control. E Mice were injected with 5 µg M2T-CD33 or controls as indicated by triangles and then challenged 2 weeks later with 0.5 × 10⁶ C1498-hCD33 cells (Day 0). The therapeutic regimen was then repeated every 4 weeks (N = 9–10). Kaplan–Meier survival curves shown. Survival significance was determined by log-rank Mantel-Cox test, compared to control.