2 
Dr. Gottesman, Chair, called the meeting of the Recombinant DNA Advisory 
Committee (RAC) Working Group on Tbxins to order at 9:00 a.m. on August 16, 
19R5. 
Dr. Gottesman said the current National Institutes of Health (NIH) Guidelines 
for Research Involving Recombinant DNA Molecules require specific RAC review 
and NIH and Institutional Biosafety Committee (IBC) approval of certain oc pen- 
man ts before initiation. Among these experiments are those involving deliberate 
formation of recombinant IN As containing genes for the biosynthesis of toxic 
molecules lethal for vertebrates at an LD 50 of less than 100 nanograms per 
kilogram body weight. A specific appendix referring to the cloning of toxins 
was constructed in 1980 by the Working Group on Tbxins. That appendix, entitled 
"Containment Conditions for Cloning of Genes Coding for the Biosynthesis of 
Molecules Tbxic for Vertebrates," specifies the contairment to be used for the 
deliberate cloning of genes coding for the biosynthesis of molecules toxic for 
vertebrates. The appendix was based on a consideration of the pharmacological 
toxicity of the toxin and specifies that experiments involving cloning of the 
genes for toxins such as botulinum toxins, tetanus toxin, diphtheria toxin, 
and Shigella dysentenae neurotoxin must be reviewed by the RAC and have NIH 
and IBC approval before initiation. 
Dr. Gottesman said three proposals involving two of these toxins are on the 
working group agenda for the August 16, 1985, meeting: (l) a request for per- 
mission to clone Shiga-like toxin (SLT) structural genes from bacterial species 
classified in the families Enterdbactenaceae or Vibnonaceae according to 
Berqey's Manual of .Systematic Bacteriology (Attachment II) ; (2) a proposal to 
remove from Biosafety Level 4 (BL4) containment K-12 host- vector systems 
expressing a hybrid gene encoding a-melanocyte stimulating hormone (a-MSH) and 
portions of diphtheria toxin (Attachment III); and (3) a request for permission 
to construct a hybrid molecule in which the gene coding for interleukin - 2 
(IL-2) is joined to a segment of the gene encoding the A subunit and portions 
of the B subunit of diphtheria toxin. The hybrid gene would be cloned in E. 
coli K-12 host- vector systems (Attachment II). 
Request for Permission to Clone Shiga-like Toxin Genes 
Dr. Gottesman said Dr. Alison O'Brien of the Uniformed Services University of 
the Pfealth Sciences (USUHS) was requesting permission to clone SLT structural 
genes (defined either by nucleotide sequence homology with SLT gene probes 
frcm FL ooli or by antigenic cross- reactivity of their gene products with 
purified FL coli SLT) frcm bacterial species classified in the families Entero- 
bactenaceae or Vibnonaceae according to Bergey's Manual of Systematic Bacteri- 
ology into FL coli K-12 under the conditions specified in Federal Register 
Volume 49, Number 179. Dr. O'Brien had previously sought and had obtained 
permission from the NIH to clone SLT from FL coli in EL coll K-12 host-vector 
systems. The language of that permission appeared in Federal Register 49, 
Number 179, and was incorporated into the NIH Guidelines as Appendix F-IV-H. 
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