51Cr‐ labelled chicken erythrocytes (E) were treated with human and C7 to form , susceptible to lysis by the terminal complement components C8 and C9 ('reactive lysis') Addition of purified and extensively washed human blood lymphocytes, but not of erythrocytes, to resulted in a similar but cell‐mediated reactive lysis. Contamination of the effector cell preparations with plasma was excluded. The reaction does not require living effector cells. Its dependency on C8 was proved by inhibition with rabbit anti‐human C8 as well as with its F(ab')2fragments. Although terminal complement components may be of importance for cell‐mediated lysis of complement‐carrying target cell, no effector role could be assigned to them in antibody‐dependent lymphocyte mediated lysis Thus, lysis of antibody‐coated chicken erythrocytes in the absence of added complement by purified human lymphocytes was not inhibited by the F(ab')2fragme