False-colour scanning electron micrograph of a small T-lymphocyte killer cell (top) which has successfully attacked a large tumour or cancer cell (bottom). The surface of the tumour cell has lost its normal covering of small projections called microvilli, which is an indication that it is losing the battle with the lymphocyte. After it is attacked by the lymphocyte, a white blood cell, the tumour cell defends itself by producing blisters, or blebs (some present here), to prevent the lymphocyte making intimate contact. If this strategy is not successful, the lymphocyte may kill the tumour cell, as here. Magnification: X 2,500 at 35mm size.