APPENDIX E 
by standard laboratory practices. Examples of class 2 agents are various 
species of salmonella, agents causing ameobic dysentery, and mumps, measles and 
rubella viruses. Class 2 agents may be used in recombinant DNA experiments. 
The NCI classifies agents such as feline sarcoma and leukemia viruses, and 
woolly monkey fibrosarcoma virus as moderate risk. 
(2) Deliberate formation of recombinants containing the genes for 
toxins of very high toxicity. Examples of this class are botu I inus toxin 
or diphtheria toxin, and venoms from insects and snakes. 
(3) Deliberate creation from plant pathogens of recombinant DNAs that 
are likely to increase either the virulence of the pathogenic material or the 
range of species susceptible to the disease. 
(4) Certain of the possible beneficial applications of DNA recombinant 
research involve the creation of organisms with the ability to carry out 
useful environmental functions. Release of such organisms into the environ- 
ment may at some point be required to test their efficacy, and certainly 
to make use of them. The guidelines state that deliberate release of any 
organism containing a recombinant DNA molecule is not to be undertaken at present. 
(5) Transfer of a drug resistance trait to m icroorgan i sms that are not 
known to acquire it naturally if such acquisition could compromise the use 
of a drug to control disease agents in human or veterinary medicine or agricul- 
ture . 
(6) Experiments must be limited in scale to quantities of fluid less 
than 10 liters with recombinant DNAs known to make harmful products. The 
guidel ines state that the Advisory Committee may make exceptions to this 
rule for particular experiments deemed to be of direct societal benefit if 
Appendix E — 8 
