Disease Associated with Immune System
DiGeorge's syndrome is characterized by the lack of a thymus The mouse model closest to this human disease would be a

recombinant mouse for CD3
nude mouse
knock-out mouse for a thymus
knock-out mouse for RAG-1 and RAG-2

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Disease Associated with Immune System
X-linked hyper IgM syndrome, resulting in high levels of serum IgM and low levels of serum IgG, is caused by a defect in CD40L expression. The specific immune event that would be prevented by a defective CD40L would be

failure of Th2 cells to provide co-stimulation for B cell proliferation
activation of B cells by T-independent antigens
failure of B cells to provide co-stimulation for Th2 activation
failure of Th2 cells to provide co-stimulation for B cell isotype switching

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Disease Associated with Immune System
Difficulties with somatic gene therapy arise from all of the following except

inserting a gene so that it will function properly
GVHD caused by mature T cells in the transplanted cells
limited life span of more mature hematopoietic cells
transducing genetic material into stem cells

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Disease Associated with Immune System
To treat HIV infections using drugs, the major problem is that

the drugs that are good inhibitors cannot by synthesized
the drugs are rapidly degraded
the drugs interfere with normal digestion
the virus particles with altered (mutant) proteases arise

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