22 
(2) E. ooli K-12 and its suppcesaor-free sib x2705, for use 
In oon^mction with; virulent lanbda vectors including but not 
limited to Charon 4A; temperate bacteriophage lambda vectors 
X YBQS CI857 and XZEQ6 cI857 ; plasmid cloning vector pBR322; and the 
ocemid cloning vectors pJC75-37, pJC75-58, pJC76, pJC77, and pHC79. 
(3) E. OTli X 2001 and its suppressor- free sib x 2363, for use in 
conjunction with all of the vectors emmerated in part two 
forx 1984 and x2705 plus the cosmid vector pJC78. 
Dr. Friedman said that an ^ working group held a telephone con- 
ference cedi on January 21, 1982, to discuss this request; that 
discussion is sutmvirized in Attachment II. He then suggested that 
RAC eveduate part one of the proposal separately. He said the ad hoc 
working group agreed that the systems described in part one, x2^7 and 
x2281 with the virulent bacteriophage lanbda vectors, meet E3C2 certifi- 
cation criteria. The major safety feature of these systems resides in 
the vectors rather than in the host; nonetheless, the hosts meet the 
EK2 requirements specified in the Guidelines. 
Cr. Maas requested an explanation of how the suppressor^ free sibs would 
be used. Dr. Qottesman said the suppressor^ free sibs would be used to 
test the virus for reversion; they wcxdd not be used for propagating 
cloned material . 
Dr. Talbot suggested that a motion be offered on the first part of the 
propos^d. Priednan moved that strains x2447 and x2281 in part one 
of the proposal be apprcved for use with those lantxte vectors certified 
for use in DP50 on the condition tlat the suppressor- free strain not 
be used as a propagation host. 
Mr. Thornton called the vote. By a vote of eleven in favor, none 
opposed, and two abstentions, the cotmdttee approved the motion. 
Dr. Friedman suggested that parts two and three of the proposed be dis- 
cussed together as both ha\« the same problems. In addition to requesting 
permission to utilize virulent lambda phage as vectors. Dr. Curtiss 
requests, in parts two and three, certification for lysogenizing lanbda 
phage and for plasmid and cosmid vectors. 
cr. Friecknan said Cr. Curtiss presented no data, as required 
for EK2 certification, on the lysogenizing phages or for the cosmid 
vectors. In order to approve plasmid vectors, data from triparentcd 
matings must be evaluated, however. Dr. Curtiss supplied no data 
pertinent to triparent£d. natings in strains xl^®^ x2705 nor for 
x2001 and x2363. 
Dr. Qottesman explained the rationale behind the EK2 approval pro- 
cedure. There eure two considerations: (1) whether the host could 
establish and spread in the ervirorment, and (2) whether the organism 
could disseminate recombinant DNA to secondary hosts. She explained 
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