Search results
Results from the WOW.Com Content Network
Due to their role in phagocytosis, macrophages are involved in many diseases of the immune system. For example, they participate in the formation of granulomas, inflammatory lesions that may be caused by a large number of diseases. Some disorders, mostly rare, of ineffective phagocytosis and macrophage function have been described, for example ...
Macrophages are long-lived and can continue phagocytosis by forming new lysosomes. [11] [13] Dendritic cells also reside in tissues and ingest pathogens by phagocytosis. Their role is not killing or clearance of microbes, but rather breaking them down for antigen presentation to the cells of the adaptive immune system. [11]
It has been known for some time that animals defend themselves against cancer by antibody-mediated or antibody-independent phagocytosis of viable tumour cells by macrophages. Recognition of viable cancer cells for phagocytosis may be based on the expression of novel antigens, senescence markers, phosphatidylserine or calreticulin.
In this state, macrophages are good antigen presenters and killers. If they receive a signal directly from an invader, they become "hyperactivated", stop proliferating, and concentrate on killing. Their size and rate of phagocytosis increases—some become large enough to engulf invading protozoa .
Professional APCs specialize in presenting antigens to T cells. [5] They are very efficient at internalizing antigens, either by phagocytosis (e.g. macrophages), or by receptor-mediated endocytosis (B cells), processing the antigen into peptide fragments and then displaying those peptides (bound to a class II MHC molecule) on their membrane. [1]
The antigen binding groove, where the antigen or peptide binds, is made up of two α-helixes walls and β-sheet. [ 3 ] Because the antigen-binding groove of MHC class II molecules is open at both ends while the corresponding groove on class I molecules is closed at each end, the antigens presented by MHC class II molecules are longer, generally ...
Macrophages are the most efficient phagocytes and can phagocytose substantial numbers of bacteria or other cells or microbes. [2] The binding of bacterial molecules to receptors on the surface of a macrophage triggers it to engulf and destroy the bacteria through the generation of a "respiratory burst", causing the release of reactive oxygen ...
2) The antibodies bind to pathogens with complementary antigen sequences, engaging in opsonization (2a), neutralisation (2b), and agglutination (2c). 3) A phagocyte (C) approaches the pathogen, and Fc region (D) of the antibody binds to one of the Fc receptors (E) on the phagocyte. 4) Phagocytosis of antibody-marked pathogen