Attachment II - Page 10 
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What tests have been used and what is the sensitivity 
of the tests? 
(b) If a virus, how is it prepared from the CNA construct? In 
what cell is the virus grcwn (any special features)? What 
medium and serum are used? How is the virus purified? What 
is its structure and purity? What steps are being taken 
(and assays used with their sensitivity) to detect and 
eliminate any contaminating materials (nucleic acids, pro- 
teins, etc.) or contaminating viruses or other organisms in 
the cells or serum used for preparation of the virus stock? 
(2) Describe any other material to be used in preparation of 
the material to be administered to the patient. For exanple, 
if a viral vector is preposed, what is the nature of the 
helper virus or cell line? If carrier particles are to be 
used, what is the nature of these? 
2. Preclinical studies, including risk -assessment studies 
Describe the experimental basis (derived frem tests in cultured 
cells and animals ) for claims about the efficacy and safety of the 
preposed system for gene delivery. 
a. Laboratory studies of the delivery system 
(1) What cells are the intended recipients of gene therapy? 
If recipient cells are to be treated in vitro and returned 
to the patient, hew will the cells be characterized before 
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