IgA class switching

Harriman, G., Bradley, A., Das, S., Rogers-Fani, P., and Davis, A. (1996). IgA class switch in I alpha exon-deficient mice. Role of germline transcription in class switch recombination./. Clin. Invest. 97, 477-485. 

Class switching When the complete heavy chain gene shown in Fig. 4 is transcribed, it generates a heavy chain for an IgM antibody since it is always the first C segment after the recombined VDJ (in this case CJ that is transcribed. To switch to making a heavy chain for a different antibody class, say IgA, the lymphocyte DNA has to undergo yet another recombination event that moves Ca next to... 

Neuroimmunological reactions. The humoral immune response in CNS is different from the immune response usually observed in blood. As a main difference, we find no switch from the IgG-class response to a more speciflc IgG-class response in the course of inflammatory disease. The pattern of intrathecal IgG/IgA/IgM synthesis remains rather constant and depends on the causes, pathophysiology, and localization of the disease process (R4). 

Antibodies of the IgG, IgA and IgE classes are made later than IgM during a primary immune response, but account for most of the antibody that is made during a memory response. Although isotype switching and affinity maturation are independent processes, they usually occur simultaneously (Fish et al., 1989), so that the increased affinity of bivalent antibodies of isotypes other than IgM is rapidly enhanced. IgG antibody is the predominant isotype in plasma and lymph, while IgA antibody predominates at mucosal surfaces and in secretions from these surfaces. 

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