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Antibodies are produced by B cells in two ways: (i) randomly, and (ii) in response to a foreign protein or substance within the body. Initially, one B cell produces one specific kind of antibody. In either case, the B cell is allowed to proliferate or is killed off through a process called clonal deletion. Normally, the immune system is able to ...
AIRE is a transcription factor expressed in the medulla [broken anchor] (inner part) of the thymus. It is part of the mechanism which eliminates self-reactive T cells that would cause autoimmune disease. It exposes T cells to normal, healthy proteins from all parts of the body, and T cells that react to those proteins are destroyed.
Meanwhile, osteoclasts, cells involved with the dissolution and reabsorption of old bone tissue, are involved in the process of osteoclastogenesis. [ 11 ] There are several environmental risks factors that also contribute to the development of rheumatoid arthritis through epigenetic modifications induced by external stimuli, which include ...
This process is called promoter escape, and is another step at which regulatory elements can act to accelerate or slow the transcription process. Similarly, protein and nucleic acid factors can associate with the elongation complex and modulate the rate at which the polymerase moves along the DNA template.
The process of differentiation into memory B cells within the germinal center is not yet fully understood. [3] Some researchers hypothesize that differentiation into memory B cells occurs randomly. [ 6 ] [ 4 ] Other hypotheses propose that the transcription factor NF-κB and the cytokine IL-24 are involved in the process of differentiation into ...
The process of V(D)J recombination is mediated by VDJ recombinase, which is a diverse collection of enzymes. The key enzymes involved are recombination activating genes 1 and 2 (RAG), terminal deoxynucleotidyl transferase (TdT), and Artemis nuclease, a member of the ubiquitous non-homologous end joining (NHEJ) pathway for DNA repair. [4]
In addition to the formed antibodies in the body there remains a small number of memory T and B cells that make up the cellular component of the immunological memory. They stay in blood circulation in a resting state and at the subsequent encounter with the same antigen these cells are able to respond immediately and eliminate the antigen.
The process of transcription is a major source of DNA damage, due to the formation of single-strand DNA intermediates that are vulnerable to damage. [53] The regulation of transcription by processes using base excision repair and/or topoisomerases to cut and remodel the genome also increases the vulnerability of DNA to damage. [53]