"White blood cells include three main subtypes; granulocytes, lymphocytes and monocytes. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells."
White blood cells, such as T cells, B cells, macrophages, and neutrophils, are the main cells that make up our immune system.
Anatomy and Physiology of the Immune System: This topic covers the different organs and tissues of the immune system and their respective structures and functions.
Innate and Adaptive Immunity: Innate immunity provides rapid defense against microbial pathogens, while adaptive immunity develops over time and provides specific defense against previously encountered pathogens.
Cell-mediated Immunity: This topic talks about the immune response driven by T cells, which includes the activation of T-helper cells, cytotoxic T cells, and regulatory T cells.
Humoral Immunity: This topic talks about the immune response driven by B cells, which involves the production of antibodies and their role in neutralizing pathogens.
Antigen Presentation and Processing: This topic covers the mechanisms of antigen processing and presentation by antigen-presenting cells such as dendritic cells.
Major Histocompatibility Complex: The MHC is a crucial component of antigen presentation, and this topic covers the different classes of MHC molecules and their roles.
Cytokines: These are signaling molecules that coordinate immune responses and facilitate communication between immune cells.
Immunoglobulins: This topic covers the structure and function of immunoglobulins, also known as antibodies.
Immune System Disorders: This topic talks about diseases caused by immune system dysfunction, such as autoimmune diseases and immunodeficiency disorders.
Vaccines and Immunization: This topic covers the development and types of vaccines, as well as their role in generating immunity against infectious diseases.
Transplant Immunology: This topic covers the immune response to transplanted organs and tissues, and the strategies used to prevent rejection.
Immunotherapy: This topic covers the use of various treatments to boost or manipulate the immune system, such as monoclonal antibodies and checkpoint inhibitors.
Immunogenetics: This topic covers the genetic basis of immune system variation and its implications for disease susceptibility and response to treatment.
Immunotoxicity: This topic covers the adverse effects of pharmaceuticals, environmental toxins, and other factors on the immune system.
Inflammation: This topic covers the role of inflammation in the immune response, as well as its role in other biological processes such as wound healing and cancer.
Microbial Pathogenesis: This topic covers the mechanisms by which pathogens evade or exploit the immune system, and the strategies used by the immune system to combat infection.
Infectious Diseases: This topic covers the different types of infectious diseases and their respective causative agents, as well as the mechanisms of transmission and prevention.
Immune Surveillance: This topic covers the mechanisms by which the immune system detects and eliminates abnormal cells, such as cancer cells.
Aging and the Immune System: This topic covers the changes that occur in the immune system as a result of aging, and the implications for disease susceptibility and response to treatment.
Allergy and Hypersensitivity: This topic covers the immune response to harmless substances that can cause allergic reactions, as well as autoimmune hypersensitivity disorders.
B cells: Responsible for producing antibodies and humoral immunity.
T cells: Responsible for cell-mediated immunity, attacking infected or abnormal cells.
Natural killer cells: Attacks infected, cancerous or normal cells that lack major histocompatibility complex (MHC) molecules.
Dendritic cells: Capturing and presenting foreign antigens to T cells.
Macrophages: Phagocytosis of foreign particles, releasing cytokines to recruit immune cells.
Neutrophils: Phagocytosis and destruction of bacteria and other foreign particles.
Eosinophils: Combats parasitic infections and allergic reactions.
Basophils: Release histamine and other pro-inflammatory molecules in response to allergens.
Mast cells: Release histamine and other vasoactive molecules in response to allergens.
Monocytes: Precursor to macrophages and dendritic cells.
Natural killer T cells: Surveillance of microbial infections and cancerous cells.
T helper cells: Activates and coordinates immune response by communicating with other immune cells. Subtypes include Th1, Th2, Th17 and Th9.
T regulatory cells: Suppresses immune response to prevent autoimmunity and maintain self-tolerance.
Memory cells: Long-lived cells that remember previous infections and facilitate faster and more robust response upon re-exposure.
Plasma cells: Specialized B cells that secrete large amounts of antibodies.
Follicular helper T cells: Helps B cells in antibody production and is found in the germinal center of lymph nodes.
"Leukocytes are found throughout the body, including the blood and lymphatic system."
"All white blood cells have nuclei, which distinguishes them from the other blood cells, the anucleated red blood cells (RBCs) and platelets."
"The different white blood cells are usually classified by cell lineage (myeloid cells or lymphoid cells)."
"They help the body fight infection and other diseases."
"Types of white blood cells are granulocytes (neutrophils, eosinophils, and basophils), and agranulocytes (monocytes and lymphocytes (T cells and B cells))."
"Monocytes, macrophages, and neutrophils are phagocytic."
"Lymphoid cells (lymphocytes) include T cells (subdivided into helper T cells, memory T cells, cytotoxic T cells), B cells (subdivided into plasma cells and memory B cells), and natural killer cells."
"Historically, white blood cells were classified by their physical characteristics (granulocytes and agranulocytes)."
"An excess of white blood cells is usually due to infection or inflammation."
"Less commonly, a high white blood cell count could indicate certain blood cancers or bone marrow disorders."
"The normal white cell count is usually between 4 × 109/L and 1.1 × 1010/L. In the US, this is usually expressed as 4,000 to 11,000 white blood cells per microliter of blood."
"White blood cells make up approximately 1% of the total blood volume in a healthy adult, making them substantially less numerous than the red blood cells at 40% to 45%."
"This 1% of the blood makes a large difference to health, because immunity depends on it."
"An increase in the number of leukocytes over the upper limits is called leukocytosis. It is normal when it is part of healthy immune responses, which happen frequently. It is occasionally abnormal, when it is neoplastic or autoimmune in origin."
"A decrease below the lower limit is called leukopenia. This indicates a weakened immune system."
"All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells."
"They help the body fight infection and other diseases."
"Monocytes, macrophages, and neutrophils are phagocytic."
"Granulocytes include neutrophils, eosinophils, and basophils, while agranulocytes consist of monocytes and lymphocytes."