Astrocytes are not susceptible to lysis by natural killer cells.

A cell population from the central nervous system, of mainly astrocytes, was prepared and their susceptibility to natural killer cell lysis was compared to YAC-1 cells and L929 cells. Two populations of natural killer cells were used: the splenocytes of mice immunized with Semliki Forest virus 3 days previously and day 5 inflammatory cells from West Nile virus-infected CBA/H mouse brain. Both cell populations showed high lytic activity on YAC-1 cells and the effector cells possessed conventional natural killer cell markers, i.e., Thy1 +/-, L3T4-, Lyt2-, GM1+. The results revealed that astrocytes are not susceptible to lysis by natural killer cells and hence argue against the hypothesis that the absolute concentration of MHC antigens on the cell surface determines the susceptibility to natural killer cell lysis.