Resistance to NK Cell-Mediated Cytotoxicity (in K-562 Cells) does not Correlate with Class I MHC Antigen Levels

Zvi Reiter, Yoram Reiter, Zvi Fishelson, Meir Shinitzky, Abraham Kessler, Avraham Loyter, Ofer Nussbaum, Menachem Rubinstein

Research output: Contribution to journalArticlepeer-review


Natural Killer (NK) cells probably function as an early line of defense against virus-infected cells and tumor cells. In all cases, the killing by NK cell-mediated cytotoxicity (NK-CMC) is not MHC-restricted and the factors which determine the sensitivity to NK-CMC have not yet been identified. A positive correlation between resistance to NK-CMC and the level of class I MHC antigen (MHC I) expression on target cells has been reported in many studies, and in some cases a functional linkage between the two has been claimed. Several other studies have shown that there is no such correlation. By employing several experimental systems, we demonstrate here a lack of correlation between the level of MHC I and the sensitivity of K-562 cells to NK-CMC. Transfer of MHC I to MHC I-negative cells via vesicles had no effect on their resistance to NK-CMC. In addition, a decrease in resistance to NK-CMC and increase of MHC I levels was observed following target-cell membrane modulation by both application of cholesterol and hydrostatic pressure. Finally, no correlation between sensitivity to NK-CMC and MHC I expression was found in three sublines of K-562 cells. Since NK-CMC is a multistage process, it is concluded that components other than class I MHC antigens have a more prominent role in modulating the sensitivity of target cells to NK-CMC.

Original languageEnglish
Pages (from-to)23-39
Number of pages17
Issue number1-2
StatePublished - 1991
Externally publishedYes


  • IFN
  • Interferon
  • MHC I
  • MHC class 1 antigens
  • NK
  • NK Cytotoxic Factor
  • NK-CMK
  • NK-Cell Mediated Cytotoxicity
  • NKCF
  • Natural killer
  • β -microglobulin
  • β m


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