When does allelic exclusion occur in B cells?
When does allelic exclusion occur in B cells?
Monospecificity of B lymphocytes is ensured by allelic exclusion during V(D)J recombination events in B cell development, which results in the generation of mature B cells with one productively and one non-productively rearranged IgH allele.
How does allelic exclusion prevent multiple heavy chain?
How does allelic exclusion prevent multiple heavy-chain rearrangements from occurring in pre-B cells? RAG1 and RAG2 are downregulated, and Tdt activity is lost so that no additional heavy-chain rearrangements can take place.
What is isotypic exclusion?
The isotypic exclusion reflects a defined developmental sequence of light chain rearrangement, with κ preceding λ, or with a much higher probability of κ rearrangement.
Which of the following disease is a good example of allelic heterogeneity?
These genes display allelic heterogeneity at their loci and are responsible for distinct disease phenotypes. Some of these diseases include alkaptonuria, albinism, achondroplasia, and phenylketonuria. For example, β-thalassemia may be caused by several different mutations in the β-globin gene.
What causes allelic exclusion?
Many regulatory processes can lead to allelic exclusion. In one instance, one allele of the gene can become transcriptionally silent, resulting in the transcription and expression of only the other allele. This could be caused in part by decreased methylation of the expressed allele.
What is the purpose of allelic exclusion?
Allelic exclusion ensures only one productively rearranged allele is expressed on the surface of each B and T cell. This is important because the adaptive immune system relies on clonal expansion of lymphocytes that are able to specifically recognize an invading pathogen.
What is light chain isotype exclusion?
cules produced by a cell have the same specificity. Further- more, in a given lymphocyte, either K or A light (L) chain, but. not both, can combine with heavy (H) chain to form a complete. Ig molecule; this is called L chain isotypic exclusion.
What does it mean to be a heterogeneous disease?
A heterogeneous medical condition or heterogeneous disease is a medical term referring to a medical condition with several etiologies (root causes), such as hepatitis or diabetes.
What does Delta f508 cause?
The cystic fibrosis-causing mutation deltaF508 affects multiple steps in cystic fibrosis transmembrane conductance regulator biogenesis.
What do you mean by allelic exclusion?
Allelic exclusion is a process by which only one allele of a gene is expressed while the other allele is silenced. This is significant as the co-expression of both alleles in B lymphocytes is associated with autoimmunity and the production of autoantibodies. Many regulatory processes can lead to allelic exclusion.
What is the purpose of somatic hypermutation?
Somatic hypermutation is a process that allows B cells to mutate the genes that they use to produce antibodies. This enables the B cells to produce antibodies that are better able to bind to bacteria, viruses and other infections.
Where does Anergy occur?
The activated immune system is one in which the white blood cells are actively mounting a response to an antigen or pathogen. Anergy, or immune intolerance, occurs when the there is a failure to mount a complete immune response to an antigen. Anergy can occur in both T and B lymphocytes.
