False-colour scannning electron micrograph of a T-lymphocyte killer cell (small cell on left),attacking a large cancer tumour cell. The T-ymphocyte,a white blood cell,must make intimate contact with the tumour cell. It does so by recognizing antigens on the tumour's surface. Following contact the tumour cell undergoes distinct structural changes; loss of microvilli (small projections,lost here),perforation and ultimately death. The tumour cell may survive,however,by budding off a number of blebs or blisters,which form a protective barrier between itself & the lymphocyte,preventing further contact. Magnification: X 2,500 at 35mm size |