Macrophage and T cells. Coloured scanning electron micrograph (SEM) showing the interaction between a macrophage (large cell) and a CD4+T cells, two components of the body's immune system. Both are types of white blood cell. Macrophages are antigen-presenting cells (APCs). They present antigens (fragments on the surface of pathogens or foreign objects) to T lymphocytes, activating them. Each T lymphocyte recognises and binds to a specific antigen. Binding of the T cell to the antigen presented by the macrophage activates the T cell. This leads to its proliferation and the activation of other immune cells that eliminate the antigen. In this case, the cells come from the same person, and so the lower T-cell is moving away having established a friendly contact. Specimen courtesy of Greg Towers and Lydia Newton, UCL. Magnification: x7000 when printed 10cm wide. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Gschmeissner, Steve |
Bildgröße: | 4572 px × 4475 px |
Modell-Rechte: | nicht erforderlich |
Restrictions: | - |