White blood cells, coloured scanning electron micrograph (SEM). Seen here are two lymphocyte (left) cells and one neutrophil (right) cell of the human immune system. Lymphocytes (T-cells or B-cells) recognise foreign antigens and destroy invaders such as viruses and bacteria. Neutrophils engulf bacteria as well as releasing various substances, such as an antibacterial enzyme (lysozyme) and oxidizing agents. Both cell types have thin projections on their surface called filopodia, which are used for support and motility. Magnification: x4750 at 6x7cm size.