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Thread: Q N^

  1. #1
    Asclepius1's Avatar
    Asclepius1 is offline Ultimate Member 537 points
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    Q N^

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    A 5-year-old boy with a history of recurrent ear infections receives his preschool booster immunization against diphthena-tetanus-pertussis He is participating in a community-sponsored study to determine the humoral immune response to tetanus toxoid (tt) His response is well below normal for age- and sex-matched children Peripheral B lymphocyte count and T lymphocyte count and function are within the reference range The antibody he makes is positive in both the passive hemagglutmation and complement-mediated lysis of tt-coated erythrocytes His antibodies do not opsonize tt-coated latex particles for phagocytosis and do not directly precipitate tt efficiently This child most likely has a defect in which of the following processes'?
    A) Affinity maturation of immunoglobulms
    B) Immunoglobulm isotype switching
    C) Recombination of heavy chain variable region genes
    D) Recombination of light chain variable region genes
    E) Somatic mutation of immunoglobulm genes

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    Asclepius1's Avatar
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    Re: Q N^

    Quote Originally Posted by Anonymous
    A 5-year-old boy with a history of recurrent ear infections receives his preschool booster immunization against diphthena-tetanus-pertussis He is participating in a community-sponsored study to determine the humoral immune response to tetanus toxoid (tt) His response is well below normal for age- and sex-matched children Peripheral B lymphocyte count and T lymphocyte count and function are within the reference range The antibody he makes is positive in both the passive hemagglutmation and complement-mediated lysis of tt-coated erythrocytes His antibodies do not opsonize tt-coated latex particles for phagocytosis and do not directly precipitate tt efficiently This child most likely has a defect in which of the following processes'?
    A) Affinity maturation of immunoglobulms
    B) Immunoglobulm isotype switching
    C) Recombination of heavy chain variable region genes
    D) Recombination of light chain variable region genes
    E) Somatic mutation of immunoglobulm genes
    b answer

  3. #3
    mital82 is offline Junior Member 510 points
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    ithink the answer is b.
    as the child has normail hemagglutination and complement mediated lysis. so we can conclude that it can recognize the tt antigen.so last 3 choices r wrong.
    also from normal hemagglutination and complement mediated lysis we can say igm is normal.
    and opsonization mainly by igG is deficient. so the antibody would not be able to switch the class.
    and that is why response is below normal.

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