objective:to compare the different features of t－cell－stimulation of dendritic－like cells (dc－like cells)induced from monocyte－macrophages derived from placentas in different gestational ages. Methods:monocyte－macrophages were separated mechanically from normal term placental tissues and second trimester placental tissues,then cultured in the transendothelial trafficking system and induced into dc－like cells. The dc－like cells were co－cultured with allogeneic t cells,in order to detect their abilities to stimulate allogeneic t cells into proliferation by cck－8 incorporation assay. Expressions of intracellular cytokines by stimulated t cells and the phenotype of dc－like cells were analyzed by facs. Results:after being cultured in the transendothelial trafficking system for 48 h,the cells which derived from the normal term placental monocyte－macrophages displayed characteristic morphology and expressed higher level surface antigen of cd80,cd86,hla－dr,and obviously stimulated the proliferation of allogeneic t cells,which could be led to a higher percentage of ifn－γ producing cells,but fewer of il－10 producing cells. However,dc－like cells,originated from second trimester placental tissues,expressed quite little levels of cd80,cd86 and hla－dr(p < 0.05)and stimulated very few allogeneic t cells to proliferation (p < 0.05). Furthermore,in the t cells stimulated by these dc－like cells ,there were small percentages of ifn－γ producing cells in cd8+ subset (p < 0.05)and large percentages of il－10 producing cells in both cd8- and cd8+ subsets. Conclusion:dc－like cells induced from monocyte－macrophages separated from different gestational ages placental tissues display functions in immunology with different biological characteristics.