engleski

Human decidual NK cell-mediated lysis of K562 transfectant cells

Problem: Interaction between NK cells and HLA-G-expressing cytotrophoblast cells plays a major role in regulating trophoblast invasion. We investigated the influence of HLA-G on FasL-mediated killing by decidual NK cells. Method of study: After density gradient isolation of decidual mononuclear cells, decidual lymphocytes were collected immediately or following 18 hour-culture in order to detect perforin and FasL mRNAs by RT-PCR. Cytotoxicity of magnetically separated CD56+ cells against K562 and K562-HLA-G was analyzed. Results: Overnight cultured decidual NK cells express FasL mRNA and are able to induce FasL protein expression in close contact with HLA-G molecule. Freshly isolated or overnight cultured CD56+ cells similarly lyse K562 and K562-HLA-G targets. FasL seems to represent a dominant mechanism of cytotoxicity for K562-HLA-G cells, while both perforin and FasL are equally involved in the lysis of K562. Conclusions: Since HLA-G induces FasL protein in NK cells, Fas/FasL-mediated killing could significantly contribute to K562-HLA-G lysis. Supported by the Ministry of Science and Technology, Republic of Croatia (Grant No. 0062029) and EMBIC (No. 512040, LSHM-CT-2004-512040).

NK cell; HLA-G; K562 transfectant cell

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