<p><b>OBJECTIVE</b>To study the impact of an agonist anti-CD(40)
monoclonal antibody 5C11 on the induction and
biological characteristics of leukemic
dendritic cells.</p><p><b>
METHODS</b>Combinations of 5C11 and different
cytokines were used to induce differentiation of leukemic blasts into
dendritic cells. Morphology was observed by
light microscopy.
Surface antigens of the induced
cells were analyzed by
fluorescence-activated cell sorting (FACS), the yields of
dendritic cell by
cell counting, the levels of
IL-6 and
IL-12 by
ELISA,
T cell proliferating activity by allo-
mixed lymphocyte reaction (MLR)
in vitro. Allogeneic
T cells were stimulated with leukemic
dendritic cells and
T-cell cytotoxicity was measured by MTT assay.</p><p><b>RESULTS</b>When cultured with combinations of 5C11 and different
cytokines, the leukemic
cells isolated from the
patients could differentiate into
dendritic cells. The morphology showed typical features of
dendritic cells, which expressed high levels of CD(40), CD(80) and CD(86). In comparison with the original
leukemia cells, the leukemic
dendritic cells secreted less
IL-6 but more
IL-12 (P < 0.05). The leukemic
dendritic cells were potent to stimulate the proliferation of allogeneic
T cells, and the latter was able to lyse the original
leukemia cells.</p><p><b>CONCLUSION</b>Leukemic blasts could be induced to differentiate into functional
dendritic cells. It may be of great value in the adoptive immunologic
therapy of
leukemia.</p>