Objective To observe in vitro effects and morphological changes of human peripheral blood dendritic cells (DCs) on the ability of lymphokine and phytohaemagglutininum (PHA) activated killer (LPAK) cells to induce apoptosis of the human hepatoma cell line (BEL-7402， B).Methods Experimental groups were divided into LD group (DCs+L+B), L group (L+B)， D group (DCs+B) and B group. The methods of neutral red uptake, ordinary light microscopy, electron microscopy, TDT mediated X-dUTP nick end labeling (TUNEL) were used. Results The difference between the D group and the B group was not distinct (P>0.05). The difference between the LD group and the L group was distinct， with DCs+LPAK >LPAK (P<0.01) in cytotoxity. Apoptotic cells were TUNEL positive in light microscopy, and apoptotic nuclei were stained yellow brown and dark brown, with size and shape varying from cell to cell. Ultrastructural change in apoptotic tumor cells comprised of compaction and condensation of nuclear chromatin， and condensation of cytoplasm and apoptotic bodies. At the same time, LPAK cells manifested the characteristics of autophagic apoptosis, and there were some autophagic bodies in it. Conclusions The combination of human blood DCs and LPAK cells could induce apoptosis of BEL-7402 cells effectively, with some LPAK cells manifesting the characteristics of autophagic apoptosis.
