Peripheral blood mononuclear cells, which are also called PBMCs or PB-MNCs, are blood cells that have round nuclei. They are critical to immune system functioning; they fight infection and foreign intruders in the body. Lymphocytes, monocytes and phagocytes are three examples of peripheral blood mononuclear cells.
Lymphocytes are white blood cells found in the immune system of vertebrates, animals with spinal columns and backbones. A scanning electron microscope (SEM) image can reveal a division between large and small lymphocytes.
Large lymphocytes are known as natural killer cells or NK cells. These PBMCs are the first line of defense against infection. Small lymphocytes include B cells and T cells, which play important roles in both antibody and non-antibody response.
Like lymphocytes, monocytes are white blood cells found in the vertebrate immune system. They are present in humans, mammals, birds, fish and reptiles. These peripheral blood mononuclear cells have multiple roles in immune system functioning. They produce and replenish various immune cells, and they respond to inflammation and infection signals.
Monocytes are produced in the bone marrow. Half of these monocytes are stored within the spleen. Those that migrate from the bloodstream to other tissues mature into different cell types, including macrophages.
Macrophages are essentially cells that monocytes produce in the tissues. Both macrophages and monocytes are phagocytes, another type of white blood cells. They offer immune protection through the ingestion of bacteria, dying cells and foreign particles.
Phagocytes are highly developed in vertebrates, especially humans. One liter of human blood contains nearly six billion of these phagocytes. Similarly to other white blood cells, they are highly critical for fighting infection, removing dead cells and maintaining healthy tissue.
Peripheral blood mononuclear cells have wide-ranging uses, from scientific research and clinical studies to cellular therapy. Healthy donors can give their blood cells for the testing of blood-borne pathogens. Donor cells are important to the study of HIV, Hepatitis B, syphilis and other infectious and auto-immune diseases. PBMCs are also used for vaccine development.
PBMCs are also vital to cellular therapy, a process that introduces new blood cells into damaged tissue to treat a particular disease. This type of therapy often focuses on hereditary diseases and may include gene therapy, stem cell treatments and cell replacement therapy.