star1
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Poliovirus can be grown in cultured monkey kidney cells through repeated passages, resulting in virus that is no longer neurovirulent. This virus can be used as a vaccine because it has become
A) attenuated
B) defective
C) inactivated
D) latent
E) recombinant
Normal healthy children are able to mount diverse antibody responses to several thousands of different antigens. This process is based primarily on which of the following DNA mechanisms?
A) Amplification
B) Conformation
C) Recombination
D) Repair
E) Replication
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
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| robin082006
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A
C
B
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The Key to Succeed is Patience.
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| doc179
Forum Guru
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 agree
A
C
B
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| Cedrick
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Cool questions Star I will remmeber them
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| Cedrick
Forum Fanatic
Topics: 320
Posts: 1,935
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A Attenueated
C.-Recombiantion
B.-Immunoglobulin isotype switching
I left my self a reminder oh it is like men in black 
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| truedeam59
Forum Elite
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Could you explan the 3rd answer
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| Chrales
Forum Newbie
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The disease of Q3 is Hyper IgM Syndrom: a genetic defect caused by a mutation in the gene for CD40 ligand on T4-lymphocytes (-->the CD 40 is on B-Lymphocytes)
The CD40 ligand is needed to help the B-Cells to switch the Immunglobulin Isotype from IgM to IgG,IgA or IgE.
The result are recurrent otitis media, sinusitis, pneumonias, and diarrhea.
The only 2 Isotypes that can opsonize antigens are IgM and IgG. Thus, if IgG can no longer be produced, opsonizing antigens will be impaired (but not absent).
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| twesting2173
Forum Senior
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note also that with hyper IgM, the excess IgM can bind to circulating cells and cause cytopenias.
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| Musuq
Forum Guru
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Posts: 425
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Agree with the answers, nice explanation about X-linked hyper IgM syndrome
A Attenueated
C.-Recombiantion
B.-Immunoglobulin isotype switching
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| Palaniappan
Forum Senior
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Please explain about the difference between attenuated,latent and inactivated....I always make mistakes in these areas
Thanx
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| star1
Forum Guru
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Posts: 827
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Attenuated = you make such changes in the cell that its still active but cant cause disease. I said cell in case of bacteria or particle in case of virus.
Latent = virus is active and can cause disease but it is present in a state of rest and waiting for the favourable condition to come. eg CMV in dorsal root ganglion
Inactivated = you have killed the cell and thus inactive to cause disease
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| MRMAVERICK
Forum Guru
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Posts: 749
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| yasmeen
Forum Guru
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Posts: 940
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A
C
B
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| Palaniappan
Forum Senior
Topics: 30
Posts: 148
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Hi ,Based on this question,I have few queries..
*Is IG M involved in opsonisation?
*What is the signi=ficance of passive hawem agglutination in immuno deficiency..?
Thanx
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