TEM observation on LAK cells killing the human rectal adenocarcinoma cells in vitro

ＴＥＭｏｂｓｅｒｖａｔｉｏｎｏｎＬＡＫｃｅｌｌｓｋｉｌｌｉｎｇｔｈｅｈｕｍａｎｒｅｃｔａｌａｄｅｎｏｃａｒｃｉｎｏｍａｃｅｌｌｓｉｎｖｉｔｒｏ￥ＤｉｎｇＹａｎｑｉｎｇ（丁彦青），ＬｉＣｈｕｎｄｅ（李春德），ＺｈａｎｇＪｉｎｈｕａ（张进华），ＺｈｕＭｅ...

TEM observation on LAK cells killing the human rectal adenocarcinoma cells in vitro

Substructural changes during interaction between lymphokine activated killer (LAK) cells and HR8348 cells were observed under transmission electron microscope (TEM). The results showed that: (1)after binding,the membranes of both LAK and HR8348 cells were thickened and condensed to various degrees,and their boundaries became unclear. Adherent plagues or junction-like strutures were formed,which were the morphological basis of effector-target stable binding; (2) some LAK cells inserted their protrusions into the depth of the target cells,and a few LAK cells penetrated into the taraet cells,which means LAK cells have the same"tumor-penetrating"function as natural killer (NK) and cytotoxic 1 lymphocytes (CTL) cells; (3) upon contact,the cytoplasmic organelles and granules of both cells were oriented toward the contact region,numerous microfilaments,microtubules,as well as lysosomes were aggregated at the site of contact,which plays some role in the lysis of the target cells; (4)upon binding,blebbing and ring punctures were apparent in the effector cells,whereas the target cells showed apoptotic or lytic necrosis. Apoptotic necrosis might be the result that non-perforin substances secreted by thet LAK cells triggered the action of endogeneous nucleotidase of the target cells by way of the receptors on the membrane, leading to the cleavage of DNA. The role of perforin,the entrance of calacium and magnesium ions,the edema of cells and the autolysis by lysosomes might be responsible for the lytic necrosis.