What is the function of macrophages?

Macrophages are white blood cells that perform many important activities in the immune system Although the general function of macrophages is to promote nonspecific innate immunity, they also help to start specific defense processes These cells are essential for inflammatory response and can be induced to target single targets such as tumor cells In the absence of foreign organisms such as bacteria and viruses, one of the functions of macrophages is to devour debris and dead tissues Macrophages destroy foreign invaders in the same way This process is also called phagocytosis In this process, macrophages extend pseudopodia to grasp surrounding objects or organic matters and put them into vesicles After that, a structure called lysosomes fused into the vesicles, destroying objects with enzymes and toxic chemicals After phagocytosis, another function becomes obvious The invader's surface molecules are recognized by immune cells (called antigens) and engulfed by macrophages, which then bind nearby helper T cells in a process called display By binding antigens to their specific molecular surfaces, macrophages ensure that other white blood cells do not mistake themselves for invaders If the helper T cell finds an antigen that matches the antigen presented by the macrophage, it will start the immune response Macrophages also participate in specific immune response when they are absorbed by T cells This macrophage function requires T cells to release compounds called lymphokines that respond to tumor cells or infected body cells These compounds bind lymphocyte receptors to the surface of macrophages and activate them to attack surrounding cells Another function of macrophages involves inflammation After tissue damage, macrophages in the area release chemicals that promote blood flow to the site and cause inflammation Inflammation, although painful, is necessary to ensure that other macrophages and immune cells reach and attack potential invaders and clear dead cells After injury, the second wave of macrophages arrived 48 hours later, which had nothing to do with phagocytosis or inflammation These macrophage releasing factors promote tissue growth, repair and differentiation to help injury recovery At present, the molecular composition of these factors is not clear, but when the damaged tissue lacks macrophages, it often recovers very slowly, which provides evidence for its existence.