OBJECTIVE LIFE SCIENCE
SIGNALLING IMMUNOLOGY CANCER
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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IgM
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IgA
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IgD
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IgG
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IgE
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Detailed explanation-1: -IgM is the first antibody secreted by the adaptive immune system in response to a foreign antigen. Monomeric IgM is a heterotetramer of approximately 180 kDa. However, the secreted form of IgM exists predominantly in a pentameric configuration with a molecular weight greater than 900 kDa.
Detailed explanation-2: -In the present study, IgG was absorbed before detection of IgM and IgA in two different IFA assays. Accordingly, the sensitivity of the IgM and IgA assays after IgG absorption, rather than the biology of the host response, might contribute to this phenomenon.
Detailed explanation-3: -The first antibodies to be produced in a humoral immune response are always IgM, because IgM can be expressed without isotype switching (see Figs 4.20 and 9.8). These early IgM antibodies are produced before B cells have undergone somatic hypermutation and therefore tend to be of low affinity.