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Glossary of scientific and technical terms in bioengineering and biological engineering
Published in Megh R. Goyal, Scientific and Technical Terms in Bioengineering and Biological Engineering, 2018
Somatic hypermutation is a high frequency of mutation that occurs in the gene segments encoding the variable regions of antibodies during the differentiation of B lymphocytes into antibody producing plasma cells.
Molecular Analysis of Immunity
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
B cells have one major function in vivo—the production of antibodies. All antibodies consist of paired heavy and light polypeptide chains, and exist in five different classes—IgM, IgD, IgG, IgA and IgE. IgG is by far the most abundant immunoglobulin, and is also the most important when it comes to protection against pathogens such as viruses and bacteria. An IgG molecule comprises four polypeptide chains, two light chains and two heavy chains, arranged so that they form a flexible Y-shape.1 The variable (V) regions of the antibody that may contribute to the antigen-binding site are formed from the amino-terminal ends, whereas the constant (C) regions determine the isotype.113-115 The great diversity of antibody molecules is generated through the recombination of a great number of gene segments. These segments rearrange during B cell development to form complete V domain exons in much the same way as TCR rearrangement.116-118 The analysis of their function is relatively straightforward, and limited to the analysis of serum antibody levels and diversity of antigenic specificity. The repertoire of antibodies is enormous, at least 1011 individual specificities in humans, achieves its remarkable diversity by a number of means.119 Most importantly, V regions are encoded through the somatic recombination of a multitude of different gene segments (V, D and J) which come together to increase the potential diversity of each complete encoded V region.116-118 The V domains of heavy chains comprise variable (V), joining (J) and diversity (D) gene segments, whereas the V domains of light chains comprise only variable (V), joining (J) gene segments. There are two light chain loci, λ and κ.120-122 Random insertions and deletions occur where these gene segments join,123 and further random mutations occur after an immunoglobulin has been expressed through somatic hypermutation seen after B cell stimulation.124,125 The most variable part of the V domains which contact the antigen are made up from three hypervariable regions (HV1, 2 and 3), also known as complementarity determining regions (CDRs), which are present in each heavy and light chain. Thus, the incredible diversity in antibody recognition is in part generated by the combinatorial diversity of the CDRs. The analysis of such rearrangements is relatively straightforward and consists of PCR and RT-PCR amplification of genomic and expressed Ig sequences, using primers that bind to consensus sequences within variable and constant regions of the heavy and light chains.126-128 When combined with DNA sequencing, ongoing Ig gene rearrangement may be monitored. Furthermore, as with CDR3 spectratyping for TCR genes, CDR3 length analysis may be performed in this way for Ig genes to give a measure of the breadth of the B cell antibody repertoire. Figure 8 shows a scheme of light chain rearrangement (upper panel) and heavy chain rearrangement (lower panel).
Hybrid Cuckoo Search with Clonal Selection for Triclustering Gene Expression Data of Breast Cancer
Published in IETE Journal of Research, 2023
P. Swathypriyadharsini, K. Premalatha
The immune system is a group of cells, tissues, and organs that function together to defend the body against foreign invaders [21]. Clonal selection depicts how antibodies behave and what they can do in the acquired immune system [22]. Clonal selection algorithm is a form of artificial immune system inspired by the clonal selection theory, which describes how B and T lymphocytes enhance their response to antigens over time, a process known as affinity maturation [23]. This algorithm concentrates on the Darwinian theory, such as selection being influenced by antigen–antibody affinity, replication by cell division, and variation by somatic hypermutation [23]. The main features of Clonal Selection Algorithm are The number of clones, which is proportional to the antibody’s affinity with respect to the antigens;The rate of mutation, which is inversely proportional to affinity
Scheduling batch processing machine problem with non-identical job sizes via artificial immune system
Published in Journal of Industrial and Production Engineering, 2018
Step 2. For each antibody, somatic recombination and somatic hypermutation are used. If the new objective function is smaller than the old one, replace the antibody; otherwise, repeat C times to somatic hypermutation for IgG, IgE, or IgA to be a new type of antibody. If the new objective function is smaller than the old one, replace the antibody.
A complete immunoglobulin-based artificial immune system algorithm for two-stage assembly flowshop scheduling problem with part splitting and distinct due windows
Published in International Journal of Production Research, 2019
After cognate interactions, somatic hypermutation is carried out to produce variant B-cell receptors which may be better than the original B-cell receptors or not. According to the cognate interactions, the scheduled product position remains unchanged, while the unscheduled product position randomly rearranges.