Isotypic determinants

Gould HJ, Beavil RL, Vercelli D IgE isotype determination epsilon germline gene transcription, DNA recombination and B cell differentiation. Br Med Bull 2000 56 908-924. 

Fear DJ, McCloskey N, O Connor B, Felsenfeld G, Gould HJ Transcription of Ig germline genes in single human B cells and the role of cytokines in isotype determination. J Immunol 2004 173 4529-4538. 

Due to experimental difficulties, little is known about the initial phase of class switching. Specific inductive stimuli for switching have not even been hypothesized for mammalian cells except for the isotype determination by IL-4. 

Several commercial kits are available to measure isotypes as well as specific anti-isotype reagents for mouse, rat, and human mAbs. The kits are expensive and care should be made to justify the need for isotype determination at any particular stage. Kits are based on various formats ... 

It seems clear that the existence of distinct isotypic determinants is due to specific conformational features of the constant region of the heavy chains of immunoglobulins. Unlike for some other protein systems, however, such as myoglobin (Atassi, 1975) and lysozyme (Atassi et al., 1976 Lee and Atassi, 1977a,b Atassi and Lee, 1978a,fo Atassi, 1978), the location of the various determinants has not been precisely mapped and correlated with particular structural features. 

The IgG molecules of all rabbits share antigenic determinants which are absent, for example, from bovine IgG. These are the isotypic determinants. (The IgG molecules of the two species share other antigenic specificities.)... 

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