RECOGNITION AND LYSIS BY NATURAL KILLERS OF TUMOR CELLS WITH PARTICIPATION OF LAMININ
N. A. Filatova,* I. I. Tyuryaeva, V. A. Ivanov
Institute of Cytology, St. Petersburg;
* e-mail: tda@peterlink.ru
According to the data obtained in the present work, the receptor complex of mouse natural killers (NK) includes
laminin, antibody to which blocks EK-activity (NKA regardless of the presence of complement. Preincubation
of mouse splenocytes with anti-laminin serum led to a decrease in their NKA towards tumor cells-targets
(CT), the NKA activity decreasing 2 times with respect to cultivated cells of rat hepatoma HTC, while
10 times—to cultivated cells of human erythroblastosis K562. Pretreatment of aplenocytes with noraml nonimmune
serum did not lead to a change of NKA. Quite different was the pattern after the tumor cell preincubation
with anti-laminin serum: pretreatment of CT K562 led to a twofold decrease in sensitivity of these cells to
NK-lysis, whereas the pretreatment of CT K562, on the contrary, made them twice sensitive to NK-lysis. Electrophoretic
separation of protein of CT plasma membranes with subsequent immunoblotting with anti-laminin
immune serum revealed the presence of laminin on HTC cell plasma membrane, which was identified as laminin
8/9 by the mass-spectrometry method, while no laminin was detected on K562 cells. Preincubation of splenocytes
with laminin did nor affect NKA with respect to CT K562 and HTC. Pretreatment of CT K562 and HTC with
laminin decreased the NKA to zero. The obtained data allow suggesting a doubtless participation of laminin and
its receptors in CT cytolysis by NK.
Key words: natural killers, carcinogenesis, splenocytes, kaminin, receptors to laminin
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