nbme1

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nbme1

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4 Posts

blueocean
Forum Senior
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Topics: 15
Posts: 195

10/18/06 - 07:04 AM

A 5-year-old boy with a history of recurrent ear infections receives his preschool booster immunization against diphtheria-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 hemagglutination 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 immunoglobulins

B) Immunoglobulin isotype switching

C) Recombination of heavy chain variable region genes

D) Recombination of light chain variable region genes

E) Somatic mutation of immunoglobulin genes

ManuNastai
Transilvanian..
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Topics: 55
Posts: 838

10/27/06 - 04:12 AM

B, has been discussed before

by the way: when is your exam?

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"Love is the only inflamation of the heart that drains in the vagina" (translation after Dr Petre Florescu, Professor of Pathology, UMF "Iuliu Hatieganu", Cluj Napoca

yasmeen
Forum Guru

Topics: 67
Posts: 936

11/02/06 - 07:09 PM

B ITS HYPER IGM SYND

ashfaque
Forum Newbie

Topics: 0
Posts: 142

11/06/06 - 04:56 AM

Answer B bc no class switching from IgM to Ig G No Opsonization plus repeated ear infection

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