Abstract
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 language | English |
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Pages (from-to) | 23-39 |
Number of pages | 17 |
Journal | Immunobiology |
Volume | 183 |
Issue number | 1-2 |
DOIs | |
State | Published - 1991 |
Keywords
- IFN
- Interferon
- MHC class 1 antigens
- MHC I
- Natural killer
- NK
- NK Cytotoxic Factor
- NK-Cell Mediated Cytotoxicity
- NK-CMK
- NKCF
- β -microglobulin
- β m