Lymphocytes vs Macrophages
Human body is composed of millions of cells. The human body faces attacks from micro-organisms, and other foreign substances. Body has its own defence mechanism. The mechanism will fight against the infections and the foreign substances. This is called immunity. Some mechanisms are designed to identify the invaders and attack them. In these instances, the memory cell will keep in memory the identity of the invaders and attack quickly when the same invader comes next time. This immunity is called specific immunity. Lymphocytes are responsible for specific immunity. The lymphocytes can identify the “enemy” and attack with specific antibodies and killer cells.
Other defence mechanisms cannot specifically identify the “enemy” but, can kill all foreign substances without identifying or keeping the identity. This is called non- specific (innate) immunity. Macrophages are one type of cells in the immune system, showing innate immunity. Macrophage will surround the foreign organism and “eat” it and kill it. Macrophages are usually in the tissues. But lymphocytes are usually in the lymphatic tissues or in the blood. Actually the MONOCYTE which is in the blood stream leaves the circulation and stay in the tissue as Macrophage. The macro means BIG. Phage means eating. The macrophages are big in size and they eat the bacteria and viruses. Depending on where it stay, the macrophages will get special names; in liver it is named as Kupffer cells, in bone osteoclast, in the lungs alveolar macrophage, and in brain micro glial cells.
Compared with macrophage, the lymphocytes are small. In normal condition they are not leaving the circulation. T lymphocytes can kill the infected cells (cyto toxic), B lymphocytes will produce antibodies against the infection.
In summary,
- Both macrophages and lymphocytes are defence cells which protect our body.
- Both cells are originally produced in the bone marrow.
- Lymphocytes are small in size compared with macrophages.
- Macrophages show phage (eating the foreign body) activity, lymphocytes are not.
- Macrophages stay in the tissue; lymphocytes are in the circulation,
- Macrophages give non-specific protection (innate immunity) but Lymphocytes give specific immunity.
1. Macrophages can also play a role in adaptive immunity through MHC class II
2. Lymphocytes do perform phagocytosis, but purely for formation of MHC