The Role Of Agonist Anti-CD40 MAb 5C11 On Leukemic Dendritic Cells

Dendritic cells (DCs) are the most potent antigen-presenting cells (APCs) specialized to initiate primary immune responses. DCs are considered as important elements in the induction of specific antitumor cytotoxic effectors. CD40 molecule is persistently expressed on the surface of DCs, and is up-regulated during their maturing processes. The engagement of agonist anti-CD40 mAb can trigger CD40 on the surface of DCs, thus activate DCs and endow them with the ability to prime CD8+ T cells directly.This paper focused on studying the impact of agonist anti-CD40 monoclonal antibody 5C11 on the induction and biological characteristics of fresh-isolated leukemic DCs. Methods: Agonist anti-CD40 mAb 5C11 in combination with different cytokines was used to differentiate leukemic blasts into DCs. The morphology was observed by light microscopy. The surface antigen of the induced cells was analyzed by fluorescence-activated cell sorting (FACS). The growth of DCs was decided by cell counting. The level of IL-6, IL-12 was assayed by relevant Elisa. T cell proliferating activity was determined by allo-MLR(mixed lymphocyte reaction) in vitro. Allogeneic T cells were stimulated with leukemic DCs and T-cell cytotoxicity was measured by MTT assay. Results: when cultured with agonist anti-CD40mAb with the supplement of different cytokines, the leukemia cells isolated from peripheral blood or bone marrow of leukemic patients could be differentiated into DCs. The morphology showed typical features of DCs, which expressed high level of CD40, CD80, CD86. In comparation with leukemia cells, leukemic DCs secreted less level of IL-6 but more IL-12. Furthermore, These leukemic DCs were potent to stimulate the proliferation of allo-T cells. Conclusion: Leukemic blasts could be induced to differentiate into functional DCs. It may be of great value in the adoptive treatment of leukemia.