Muramyl dipeptide CD10 monoclonal antibody immunoconjugates inhibited acute leukemia in nude mice

Minimal residual disease (MRD) is one of the causes of leukemia recurrence. Previously, we developed anti-CD10 mAb conjugated to muramyl dipeptide immunoconjugate (MDP-Ab) for immune enhancement. The present study aimed to investigate anti-leukemia effect of MDP-Ab administered via different methods in leukemia ectopic graft nude mouse model. BALB/c nude mice were injected with Nalm-6 cells subcutaneously to establish leukemia xenografts in nude mice as a model. MDP-Ab or/and human lymphocytes (LYM) was injected into different sites of the nude mice. Immunohistochemistry staining of CDs in the bone marrow, liver and spleen was performed. IFN-gamma was detected by ELISA. We detected the metastasis of leukemia cells to the liver, spleen and bone marrow in nude mouse leukemia model. MDP-Ab and LYM inhibited the growth of tumors, and simultaneous injection of MDP-Ab and LYM into the tumor inhibited the growth of tumors. IFN-gamma levels in MDP-Ab (ca) + h-LYM (ca) group, MDP-Ab (ca) + h-LYM (ip) group, MDP-Ab (iv) + h-LYM (ip) group and PBS (ca) + h-LYM (ca) group were significantly higher than those in control group, while IFN-gamma level in MDP-Ab (ca) + h-LYM (ca) group was the highest. Moreover, MDP-Ab and h-LYM promoted the expression of hCD4 and hCD8, with the highest expression in MDP-Ab (ca) + h-LYM (ca) group. In conclusion, MDP-Ab effectively promoted the production of IFN-gamma, enhanced the antitumor immunity of T lymphocytes and inhibited leukemia.