Clone (B-cell biology)
Encyclopedia
The process of immunological B-cell
maturation involves transformation from an undifferentiated B cell
to one that secretes antibodies with particular specificity. This differentiation and activation of the B cell
occurs most rapidly after exposure to antigen by antigen-presenting cell
s in the reticuloendothelial
system, and under modulation by T cell
s, and is closely intertwined with affinity maturation
. B cell
s that respond most avidly to antigen are preferentially allowed to proliferate and mature, a process known as clonal selection
.
In lymphocytic
neoplastic diseases such as multiple myeloma
and lymphoma
, but also other illnesses, there can be a massive expansion of a single B-cell clone, detectable by measuring the excessively-produced antibodies, measured in a serum protein electrophoresis
test or peripheral blood flow cytometry
. Such an expansion is said to be "monoclonal", and monoclonal antibodies
produced by such a group of B cells can cause illnesses such as amyloidosis
and lupus
, or can be indicative of an underlying malignancy. The concept of clonality is closely associated with malignancy
, for example in diagnosing lymphomatoid skin
lesions. The expansion of a particular clone of immune B cell
s is usually interpreted by clinicians as evidence of unrestricted cell growth, the hallmark of cancer
.
B cell
B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction...
maturation involves transformation from an undifferentiated B cell
B cell
B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction...
to one that secretes antibodies with particular specificity. This differentiation and activation of the B cell
B cell
B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction...
occurs most rapidly after exposure to antigen by antigen-presenting cell
Antigen-presenting cell
An antigen-presenting cell or accessory cell is a cell that displays foreign antigen complexes with major histocompatibility complex on their surfaces. T-cells may recognize these complexes using their T-cell receptors...
s in the reticuloendothelial
Reticuloendothelial system
"Reticuloendothelial system" is an older term for the mononuclear phagocyte system. The mononuclear phagocyte system consists primarily of monocytes and macrophages. The spleen is the largest unit of the mononuclear phagocyte system. The monocyte is formed in the bone marrow and transported by the...
system, and under modulation by T cell
T cell
T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in cell-mediated immunity. They can be distinguished from other lymphocytes, such as B cells and natural killer cells , by the presence of a T cell receptor on the cell surface. They are...
s, and is closely intertwined with affinity maturation
Affinity maturation
In immunology, affinity maturation is the process by which B cells produce antibodies with increased affinity for antigen during the course of an immune response. With repeated exposures to the same antigen, a host will produce antibodies of successively greater affinities. A secondary response...
. B cell
B cell
B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction...
s that respond most avidly to antigen are preferentially allowed to proliferate and mature, a process known as clonal selection
Clonal selection
The clonal selection hypothesis has become a widely accepted model for how the immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens invading the body....
.
In lymphocytic
Lymphocyte
A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...
neoplastic diseases such as multiple myeloma
Multiple myeloma
Multiple myeloma , also known as plasma cell myeloma or Kahler's disease , is a cancer of plasma cells, a type of white blood cell normally responsible for the production of antibodies...
and lymphoma
Lymphoma
Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...
, but also other illnesses, there can be a massive expansion of a single B-cell clone, detectable by measuring the excessively-produced antibodies, measured in a serum protein electrophoresis
Serum protein electrophoresis
Serum protein electrophoresis is a laboratory test that examines specific proteins in the blood called globulins. Blood must first be collected, usually into an airtight vial or syringe...
test or peripheral blood flow cytometry
Flow cytometry
Flow cytometry is a technique for counting and examining microscopic particles, such as cells and chromosomes, by suspending them in a stream of fluid and passing them by an electronic detection apparatus. It allows simultaneous multiparametric analysis of the physical and/or chemical...
. Such an expansion is said to be "monoclonal", and monoclonal antibodies
Monoclonal antibodies
Monoclonal antibodies are monospecific antibodies that are the same because they are made by identical immune cells that are all clones of a unique parent cell....
produced by such a group of B cells can cause illnesses such as amyloidosis
Amyloidosis
In medicine, amyloidosis refers to a variety of conditions whereby the body produces "bad proteins", denoted as amyloid proteins, which are abnormally deposited in organs and/or tissues and cause harm. A protein is described as being amyloid if, due to an alteration in its secondary structure, it...
and lupus
Systemic lupus erythematosus
Systemic lupus erythematosus , often abbreviated to SLE or lupus, is a systemic autoimmune disease that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage...
, or can be indicative of an underlying malignancy. The concept of clonality is closely associated with malignancy
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
, for example in diagnosing lymphomatoid skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
lesions. The expansion of a particular clone of immune B cell
B cell
B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction...
s is usually interpreted by clinicians as evidence of unrestricted cell growth, the hallmark of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
.