Natural killer cell activity in chickens: Target cell analysis and effect of antithymocyte serum on effector cells

A battery of lymphoid and nonlymphoid cells was examined for susceptibility to lysis by natural killer cells of chickens. Several susceptible targets were recognized, and most susceptible among these were cells of line LSCC-RP9, derived from a lymphoid tumor induced by Rous-associated virus 2. The natural killer reactivity against LSCC-RP9 target cells did not appear to be directed against an antigen(s) induced by Rous-associated virus 2 because other lymphoid and nonlymphoid cells infected with this were resistant to lysis in vitro by natural killer cells. The effector cells of natural killer reactivity in chickens were refractory to treatment with potent anti-T-cell and anti-B-cell sera. Inoculation of Marek's disease virus in line 15 x 7 chickens resulted in enhanced natural killer cell activity, and the effector cells of this enhanced activity were also resistant to anti-T-cell serum.