24 
clause should H(2 certification criteria be changed. He v#ondered 
tether would qualify as an 0(2 host inder the new criteria. 
Ck:. Levine replied that those questions would have to be considered 
by the CK2 wor)cing group. Che possibility would be to accept, as a 
naxinun pemissible level, the sirvival \mlues of x^^^^ hunan 
gut. Alternatively, the wor)cing group may have to deal with the 
possibility that x^^^^ ^ debilitated in the human gut as 
anticipated. Ckr. Liberman pointed out that other systems have been 
decertified, and urged that the EX2 working group ree/aluate xl776's 
status as an QC2 certified vector. 
Dr. Gotteanan suggested parts two and three of Ckr. Curtiss' request 
should be deferr^ as: (1) the infonution provided is not adeqiBte 
to evaluate the host-vector systems vis-a-vis the EX2 criteria, and 
(2) if the EX2 criteria is reconsidered, reconsideration would have 
important implications fior Cr. Qartiss' proposed. 
Cr. Friedman moved that the fotr hosts (xl984, x2705, x^OOl, and x2363) 
be eccepted for use with the virulent lanfxla vectors cxi cxxtUtion that 
the suppressor^ free strains not be used em propagation hosts. Consider^ 
ation of cosmid, plasmid and lysogenic lamb^ vectors is deferred 
ir:til more information is obtained. Maas seconded the motion. 
Mr. Thornton called the motion. By a vote of eleven in favor, none 
opposed, and focr abstentions, the RAC approved the motion. 
Dr. Levine said that 
"Vhereas QC2 systems imply and are meant to result in a high 
degree of oontaiment, and 
"Vhereas bacterial hosts in such systans are meant to be highly 
defective in their ability to survive in the environment, as well 
as in manmalian intestine, and 
■Vhereas the guidelines fior EX2 criteria were designed before much 
credible scientific data on these points were available, and 
■Ti^iereM data have recently come to light from human feeding 
experiments with 0(2 hosts with and without plaanid pGR322 that 
demonstrated increased persistence of the host containing plasmid 
pBR322,- 
he would move that the certification criteria £br EK2 host-vector systems 
be reconsidered by the EK2 working group specifically to consider 
making human feeding studies vhich ^eld the most relevant data, one 
of the criteria. 
Dr. Ahmed asked if the working group would report to RAC. Mr. Thornton 
said it would. It was stated that vhile many RAC menbers would agree 
to have the certification criteria reconsidered by the EK2 working 
( 353 ) 
