Clusters of Differentiation

Clusters of Differentiation Definition Clusters of differentiation – a system of classifying lymphocytes according to the collections of antigens on the surface of their cell membranes, also called CD markers. Each CD has a specific role in cell signaling and communication, guiding cell function and response. CDs are critical to the normal function of the immune system. […]

Read More

Macrophage – Definition and Function

Macrophage Definition A monocyte that leaves the blood circulation and takes up residence in the tissues. Once there, the cell undergoes several changes: it greatly enlarges. it develops pseudopods (footlike projections) that permit it to move through tissue. it increases the amount of lysozyme its granules contain, increasing its ability to consume cellular debris. Macrophage Function Macrophages, […]

Read More

Colony-stimulating factors (CSFs)

Colony-Stimulating Factors Definition Colony-Stimulating Factors are molecules that stimulate the growth of leukocytes (white blood cells) in the bone marrow. The body produces minute quantities of CSFs to regulate leukocyte production, maintaining the various types of leukocytes at appropriate levels to meet the needs of immune function. CSF production increases during infection and other demands for higher […]

Read More

Mast Cell – Definition and Function

Mast Cell Definition Mast Cell – a granulated leukocyte that resides in tissues throughout the body. When the immune response stimulates mast cells, they release prostaglandins, histamine, and other biochemicals from their granules. Mast cells are primarily responsible for the symptoms that are the hallmark of the hypersensitivity reaction: inflammation, itching, skin rash, coughing, and sneezing. Mast cells have an […]

Read More

Complement Cascade – Definition, Deficiencies

Complement Cascade Definition Complement Cascade is  the series of events that take place when an antibody binds with an antigen, activating the complements. Complements are proteins that participate in immune and inflammatory processes, acting primarily to kill antibody-marked cells. The biochemical interactions that take place with their activation ultimately lead to the formation of a protein structure called […]

Read More

Major Histocompatability Complex (MHC) – Class I, II, III

Major Histocompatability Complex Definition and Types Major Histocompatability Complex Definition (MHC) – The group of genes, located on chromosome 6, that determine the human leukocyte antigens (hlas) the body’s cells carry on their cell membranes. HLAs are unique proteins that cell membranes display to identify themselves to the immune system. There are three types of MHC: Class I MHC […]

Read More

Cytokines Definition

Definition of Cytokines A large family of proteins that mediate and regulate the immune response. leukocytes (white blood cells) produce this proteins. There are more than 100 cytokines, which may act independently or synergistically with others. Among the actions of cytokines are cell homing and direction (drawing leukocytes to the site of infection or injury), inflammation response, and stimulation of the numerous […]

Read More

Monoclonal Antibodies (MAbs)

Monoclonal Antibodies Definition Antibodies produced in a laboratory using recombinant DNA technology. MAbs derive from cloned mouse spleen cells (hence the designation “monoclonal”) containing the desired antibody fused with human myeloma cells. Mouse cells have proteins very similar to the proteins of human cells. Human myeloma cells, because they are cancer cells, have the ability to replicate […]

Read More

Gammaglobulin – Definition

Definition of Gammaglobulin Gammaglobulin – a solution of immunoglobulins collected from the plasma of donated blood or from donated plasma. The highest concentration is of immunoglobulin E (IgE). Health-care providers administer gammaglobulin by intramuscular or intravenous injection to provide rapid immune protection for exposure to infectious diseases such as hepatitis. Though the protection is temporary, it helps prevent infection until the person’s immune system can […]

Read More

Monokines – Definition

Monokines Definition Cytokines that convey biochemical messages among monocytes (white blood cells in the blood circulation) and macrophages (white blood cells that reside in the tissues). Monokines direct the actions of these immune cells during the immune response, stimulating and coordinating numerous functions. There is some overlap between monokines and lymphokines (which lymphocytes produce). See also COMPLEMENT CASCADE; IMMUNE SYSTEM; INTERFERONS; INTERLEUKINS; LEUKOCYTE; […]

Read More