What are the cells of the immune system?
What Are the Cells of the Immune System?
The immune system is powered by specialized cells, all of which start as stem cells in the bone marrow before differentiating into distinct types with unique functions. These immune cells are known as white blood cells, or leukocytes, which are divided into three primary classes: granulocytes, lymphocytes, and monocytes. Each plays a unique role in defending the body, working together to boost your immunity and protect against infections.
Granulocytes: The Rapid Responders
Granulocytes, which make up 50-60% of all leukocytes, are the body’s first line of defense in the innate immune system. There are three types:
Neutrophils: The most abundant type of white blood cell, neutrophils target foreign material and bacteria. They engulf and digest these invaders using enzymes and other chemicals, making them powerful immune system boosters.
Eosinophils and Basophils: While less common, eosinophils focus on parasites in the skin and lungs, and basophils release histamine to cause inflammation. This inflammation draws additional blood and immune cells to the infection site, helping to boost your immunity by initiating a strong response.
Lymphocytes: Targeted and Lasting Defense
Lymphocytes comprise 30-40% of leukocytes and handle viral and bacterial infections through targeted attacks:
B Cells: B cells mature in the bone marrow and produce antibodies specific to particular pathogens. When activated, they mature into plasma cells, multiplying to produce millions of antibodies that identify and neutralize invaders.
T Cells: T cells mature in the thymus and directly attack infected cells. Killer T cells, for example, can detect and destroy cells that are harboring viruses, acting as a natural immune system booster by eliminating infected cells.
Monocytes and Macrophages: The Clean-Up Crew
Monocytes make up about 7% of leukocytes and evolve into macrophages once they enter tissue. Macrophages, the largest immune cells, roam through tissues, engulfing and digesting pathogens. They also play a role in cleaning up cellular debris, supporting the body’s healing process after an infection and further acting as immune system boosters.
Dendritic Cells: The Bridge Between Immunity Types
Dendritic cells capture antigens (foreign substances) and present them to T-cells within lymphoid organs like the lymph nodes, spleen, and thymus. This vital function bridges the innate and adaptive immune systems, enabling a more specific and long-lasting immune response to threats.
Working Together to Boost Your Immunity
These immune cells work in concert, from the rapid-response neutrophils to the specialized B and T cells, to ensure the body is well-protected. Supporting your immune system with a nutrient-rich diet, regular exercise, and immune-boosting supplements can help keep these cells performing optimally.
Sources:
Granulocytes and Neutrophils in Innate Immunity
Murphy, K., Weaver, C. (2016). Janeway's Immunobiology. Garland Science.
Lymphocytes and Adaptive Immunity
Abbas, A. K., Lichtman, A. H., Pillai, S. (2017). Cellular and Molecular Immunology. Elsevier.
Monocytes and Macrophages in the Immune Response
Gordon, S., Taylor, P. R. (2005). Monocyte and macrophage heterogeneity. Nature Reviews Immunology, 5(12), 953–964.
Dendritic Cells and Antigen Presentation
Mellman, I., Steinman, R. M. (2001). Dendritic Cells: Specialized and Regulated Antigen Processing Machines. Cell, 106(3), 255-258.