CD5 (protein)
Encyclopedia
CD5 is a cluster of differentiation
found on a subset of IgM
-secreting B cell
s called B-1 cell
s, and also on T cell
s. B-1 cells have limited diversity of their B-cell receptor
due to their lack of the enzyme terminal deoxynucleotidyl transferase
(TdT) and are potentially self-reactive. CD5 serves to mitigate activating signals from the BCR so that the B-1 cells can only be activated by very strong stimuli (such as bacterial proteins) and not by normal tissue proteins. CD5 was used as a T-cell marker until monoclonal antibodies
against CD3
were developed.
In humans, the gene is located on the long arm of chromosome 11. There is no ligand confirmed, even if CD72, a C-type lectin, may be considered a probable ligand.
T cells express higher levels of CD5 than B cells. CD5 is upregulated on T cells upon strong activation. In the thymus
, there is a correlation with CD5 expression and strength of the interaction of the T cell towards self-peptides.
marker for T-cells, although not as sensitive as CD3. About 76% of T-cell neoplasms are reported to express CD5, and it is also found in small lymphocytic lymphoma, hairy cell leukaemia, and mantle cell lymphoma
cells. It is commonly lost in cutaneous T-cell lymphoma, and its absence can be used as an indicator of malignancy in this condition. The absence of CD5 in T cell acute lymphoblastic leukaemia, while relatively rare, is associated with a poor prognosis.
Cluster of differentiation
The cluster of differentiation is a protocol used for the identification and investigation of cell surface molecules present on white blood cells, providing targets for immunophenotyping of cells...
found on a subset of IgM
IGM
IGM as an acronym or abbreviation can refer to:* Immunoglobulin M , the primary antibody against A and B antigens on red blood cells* International Grandmaster, a chess ranking* intergalactic medium* Intragroup medium - see: Intracluster medium...
-secreting 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 called B-1 cell
B-1 cell
B-1 cells are a sub-class of B cell lymphocytes that are involved in the humoral immune response. They are not part of the adaptive immune system,as they have no memory, but otherwise, B-1 cells perform many of the same roles as other B cells: making antibodies against antigens and acting as...
s, and also on 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. B-1 cells have limited diversity of their B-cell receptor
B-cell receptor
The B-cell receptor is a transmembrane receptor protein located on the outer surface of B-cells. The receptor's binding moiety is composed of a membrane-bound antibody that, like all antibodies, has a unique and randomly-determined antigen-binding site...
due to their lack of the enzyme terminal deoxynucleotidyl transferase
Terminal Deoxynucleotidyl Transferase
Terminal deoxynucleotidyl transferase , also known as DNA nucleotidylexotransferase or terminal transferase, is a specialized DNA polymerase expressed in immature, pre-B, pre-T lymphoid cells, and acute lymphoblastic leukemia/lymphoma cells...
(TdT) and are potentially self-reactive. CD5 serves to mitigate activating signals from the BCR so that the B-1 cells can only be activated by very strong stimuli (such as bacterial proteins) and not by normal tissue proteins. CD5 was used as a T-cell marker until 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....
against CD3
CD3
CD3 or CD-3 may be:* CD3 , an antigen, cluster of differentiation protein , part of the T cell receptor complex on a mature T lymphocyte* Ford CD3 platform* MediaMax CD-3, copy protection scheme* MiniCD, a 3-inch CD...
were developed.
In humans, the gene is located on the long arm of chromosome 11. There is no ligand confirmed, even if CD72, a C-type lectin, may be considered a probable ligand.
T cells express higher levels of CD5 than B cells. CD5 is upregulated on T cells upon strong activation. In the thymus
Thymus
The thymus is a specialized organ of the immune system. The thymus produces and "educates" T-lymphocytes , which are critical cells of the adaptive immune system....
, there is a correlation with CD5 expression and strength of the interaction of the T cell towards self-peptides.
Immunohistochemistry
CD5 is a good immunohistochemicalImmunohistochemistry
Immunohistochemistry or IHC refers to the process of detecting antigens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno," in reference to antibodies used in the procedure, and...
marker for T-cells, although not as sensitive as CD3. About 76% of T-cell neoplasms are reported to express CD5, and it is also found in small lymphocytic lymphoma, hairy cell leukaemia, and mantle cell lymphoma
Mantle cell lymphoma
Mantle cell lymphoma is one of the rarest of the non-Hodgkin's lymphomas , comprising about 6% of NHL cases. There are only about 15,000 patients presently in the U.S. While it is difficult to treat and seldom considered cured, investigations into better treatments are actively pursued worldwide...
cells. It is commonly lost in cutaneous T-cell lymphoma, and its absence can be used as an indicator of malignancy in this condition. The absence of CD5 in T cell acute lymphoblastic leukaemia, while relatively rare, is associated with a poor prognosis.