Recombinant DNA Advisory Committee - 09/14-15/92 
submitted by the investigators are insufficient to conclude that this expression system can 
safely be used by laboratory workers. 
The actual protocol for obtaining gene expression with the proposed system is complex, 
involving 16 separate procedures. Some of these steps are extremely intricate, including 
electroporation, creating cDNA, mRNA, etc. There is a high likelihood that some 
investigators may not be able to get the system to work. In that case, investigators may 
tamper with the system beyond the procedures that have been outlined. In some 
instances, laboratory workers who are not knowledgeable enough to understand all of the 
complexities and requirements of particular biosafety levels may use the kit. 
Although this expression system may not be extremely hazardous to the investigators who 
purchase it, there remains the likelihood of pathogenicity if not handled under the 
proper containment conditions. 
Review-Dr. Hirano 
Dr. Hirano stated that she was in agreement with the comments made by Dr. Schaechter, 
in particular, the possible generation of infectious viral particles. The investigators have 
not supplied sufficient data to support the safety of this expression vector system despite 
the inclusion of three safety features that have been engineered into the system. 
Other Comments 
Dr. Post stated that he would like more background information regarding the 
classification of SFV as a BL3 agent. Ms. Buc requested that the investigators provide 
information about the disclosure of information to the purchaser. What kinds of 
warnings will be issued? What information will be included with the kit? Is there a 
manual? 
Dr. D. Miller asked if people who travel to Africa are capable of becoming infected by 
this agent and transport it back to the U.S? Dr. Schaechter explained that this is not an 
issue of concern. 
Presentation-Dr. Temple 
Dr. Temple presented a summary of new data that the RAC members did not review 
prior to the meeting. He explained that this new data may address the issue of 
generation of replication competent vims using this system. These experiments were 
designed to determine the combination frequency of the helper vims with the vector. 
"Leakiness" of viral particles occurs at a rate of 1 in 10 6 cells. The term "leakiness" 
refers to uptake by any means, including: (1) passive endosomal uptake, (2) exogenous 
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