IG isotypes

Snapper, C.M. and Paul, W.E. (1987) Interferon-gamma and B cell stimulatory factor-1 reciprocally regulate Ig isotype production. Science 236, 944-947. 

Mercuric chloride in the BN rat gives a lymphoproliferation in spleen and lymph nodes, including B and T helper cells, an increase in the number of Ig containing cells resulting in a rise in all serum Ig isotypes and an early thymic atrophy [196]. The kinetics of the increase in the serum level of various Ig isotypes were similar to that observed for IgE, suggesting spontaneous autoregulation, which could involve suppressor T cells [ 197, 198] and/or auto-anti-idiotypic antibodies [ 199]. 

CD4+ ] Provides help to b cells, including TFI2 ) Ig isotype switching... 

The source and quality of the lymphocytes and the antibody titer of the desired antibodies within an individual will influence the difficulty of producing antibodies from a library derived from that individual. The sources of lymphocytes that have been used successfully to produce human antibodies of the same specificity as the subject s serum antibodies have been peripheral blood lymphocytes from leukophoresis (20), thyroid lymphocytes (18,21), and lymphocytes from lymph nodes draining the site of the immune response (22) The serum reactivity of the donor should be analyzed in as much detail as possible in order to clone Ig isotypes and subclasses responsible for the response of interest. Subclass-specific antisera can be used in antigen-specific ELISA to achieve this. 

At least two separate reverse transcription reactions should be carried out, one to generate LC cDNA and another to generate HC (Fd) cDNA. At this point, the choice of the 3 -pnmers used will determine the range of Ig isotypes expressed in the library (for primers, see Table 1). For example, to generate a... 

Simultaneous staining In a simultaneous double stain, the primary antibodies can be applied simultaneously. The advantage of this method is that it is less time-consuming because the reagents can be mixed together. However, the technique can only be used, if suitable primary antibodies are available. Two methods can be adopted A direct method with directly-labeled primary antibodies, or an indirect method based on unlabeled primary antibodies raised in different host species, or of different Ig isotype or IgG subclass (4). 

An important issue in the neutralization assay is the amount of therapeutic protein product to add. This dose should be based on the dose-response curve of the protein in the assay. The reduction should be in the linear part of the curve and be significant enough to be reliably testable in the assay. The titer of the neutralization is often expressed in units. The highest dilution of the serum with a significant inhibition is defined to contain one neutralizing unit. Sometimes the activity is expressed in arbitrary units using an animal antiserum as reference. Further characterization of the antibodies may include evaluation of Ig isotype and affinity. Although alternative methods may be employed, the BIAcore assay has become the standard for these types of analyses. 

Figure 32.9. Schematic representation of Type I hypersensitivity. Induction Resident respiratory tract dendritic cells (DC) take and process antigen, mature, migrate to the draining lymph nodes, and present antigen to T lymphocytes. Activated T-lymphocytes, in turn, activate B-cell differentiation into antibody-producing plasma cells. IL-4 promotes Ig isotype class switching from IgM to IgE and promotes mast cell development. IgE is associated with mast cells. Elicitation Allergen crosslinks the mast-cell-bound IgE, thereby causing the release of preformed mediators and cytokines. (See Table 32.7.) Inflammation and bronchoconstriction occur.

Punnonen, J. and de Vries, J.E. (1994). IU13 induces proliferation, Ig isotype switching, and Ig synthesis by immature human fetal B cells. J. Immunol. 152, 1094-1102. 

Zhang K, Cheah H-K, Saxon A Secondary deletional recombination of rearranged switch region in Ig isotype-switched B cells. A mechanism for isotype stabilization. J Immunol 1995 154 2237-2247. 

Ig isotypes or classes of antibodies (IgA, IgD, IgE, IgG, IgM) generated under different circumstances. 

Ma CS, Pittaluga S, Avery DT et al 2006 Selective generation of functional somatically mutated IgMCD27, but not Ig isotype-switched, memory B cells in X-linked lymphoproliferative disease. Clin Invest 116 322—333... 

The immune system has three basic components humoral, cell-mediated, and innate (nonspecific) immime responses. Humoral immunity is primarily associated with B lymphocytes and the production of antibodies, also known as immimoglobulins (Ig). Differentiated B cells produce five Ig isotypes, each with unique stracture and function IgG, IgM, IgD, IgE, and IgA. For example, IgE is associated with allergic type 1 immediate hypersensitivity reactions, and IgA (a secretory antibody) is foimd in bodily secretions. 

Three isotypes, IgM, IgD and IgT (also called IgZ in zebrafish) have been identified in almost all studied species belonging to the main orders of teleost fish. The main exception is that IgT has not been found thus far in the channel catfish (I. punctatus) (Edholm et al, 2010,2011). IgM is the most ancient and the only isotype functionally conserved in all jawed vertebrates. IgD has been found in all jawed vertebrate groups except birds, indicating that it is also a primordial antibody class despite its highly plastic structure and unclear function in evolution (Edholm et al, 2010, 2011). Other Ig isotypes have evolved to play specialized roles either within mucosal or systemic compartments. In mammals and birds, the IgM, IgG and IgY isotypes have major roles in systemic responses, while IgA is the main player in mucosal areas. In amphibians, IgM and IgY play a prevalent role in systemic immunity whereas IgX is an isotype chiefly expressed in the gut (Flajnik, 2010). The fish IgT is a mucosal-epithelial Ig preferentially... 

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