White blood cell. Coloured scanning electron micrograph (SEM) of an unidentified white blood cell or leucocyte. There are several types of white blood cell, with different functions. Many of them (including macrophages and moncytes) can ingest foreign particles, including bacteria. Eosinophils and basophils are involved in inflammatory and allergic response. T-lymphocytes carry out cell-mediated immunity, including killing virus-infected cells. B-lymphocytes produce antibodies. Magnification unknown.