Search results
Results from the WOW.Com Content Network
Macrophages also play a role in human immunodeficiency virus (HIV) infection. Like T cells, macrophages can be infected with HIV, and even become a reservoir of ongoing virus replication throughout the body. HIV can enter the macrophage through binding of gp120 to CD4 and second membrane receptor, CCR5 (a chemokine receptor).
Macrophages are found throughout the body in almost all tissues and organs (e.g., microglial cells in the brain and alveolar macrophages in the lungs), where they silently lie in wait. A macrophage's location can determine its size and appearance. Macrophages cause inflammation through the production of interleukin-1, interleukin-6, and TNF ...
Macrophages are versatile cells that reside within tissues and produce an array of chemicals including enzymes, complement proteins, and cytokines. They can also act as scavengers that rid the body of worn-out cells and other debris and as antigen-presenting cells (APCs) that activate the adaptive immune system. [36]
In general, phagocytes patrol the body searching for pathogens, but are also able to react to a group of highly specialized molecular signals produced by other cells, called cytokines. The phagocytic cells of the immune system include macrophages, neutrophils, and dendritic cells.
Foamy macrophages are also found in diseases caused by pathogens that persist in the body, such as Chlamydia, Toxoplasma, or Mycobacterium tuberculosis. In tuberculosis (TB), bacterial lipids disable macrophages from pumping out excess LDL, causing them to turn into foam cells around the TB granulomas in the lung. The cholesterol forms a rich ...
Light microscopic video sequence of a neutrophil from human blood phagocytosing a bacterium. Neutrophils, macrophages, monocytes, dendritic cells, osteoclasts and eosinophils can be classified as professional phagocytes. [10] The first three have the greatest role in immune response to most infections. [11]
Macrophages are diffusely scattered in the connective tissue and in liver (Kupffer cells), spleen and lymph nodes (sinus histiocytes), lungs (alveolar macrophages), and central nervous system (microglia). The half-life of blood monocytes is about 1 day, whereas the life span of tissue macrophages is several months or years.
In general, monocytes and their macrophage and dendritic cell progeny serve three main functions in the immune system. These are phagocytosis , antigen presentation, and cytokine production. Phagocytosis is the process of uptake of microbes and particles followed by digestion and destruction of this material.