June E. Osborn, M. D. - 2 
make M protein which conveys an anti-phagocytic resistance to the 
bearer. Pneumococci make a capsular polysaccharide which serves a 
similar function. Diphtheria bacilli are entirely innocuous unless 
they themselves are infested with a lysogenic phage, and even then 
proper iron concentrations and other environmental conditions are 
necessary before toxin production can proceed .... and so forth. It 
is interesting to note that even in the case of drug resistance where 
much of our new infectious disease problems lie, the multiply drug- 
resistant tubercle bacillus has reduced virulence as a correlative 
property. 
I have conducted this brief exercise in medical microbiology to 
establish several points: 
1) that emphasis on the human host working in the environment of 
potentially "new" microorganisms is appropriate; 
2) that dosage is an important element in known pathogenetic 
microbial disease and so sensible efforts at containment - with 
particular attention paid when microorganisms are at high con- 
centration - can be imposed with a degree of confidence; 
3) that known, highly virulent pathogens are in general the product 
of marvelous evolutionary adaptation which allows them to co-exist 
in the so-called "carrier state" far more often than to cause disease 
in their human host. (In this context, the proposal to deal with 
DNA from viral pathogens at a level of containment no higher than 
that appropriate to the parent virus seems eminently sensible). 
The broader point I would like to make is that biology in general, 
and infectious disease microbiology in particular, submit to the 
same rational analysis as do other arenas of science; and while 
unknowns remain, much hard data and experience can be brought to 
bear on such discussions as the present consideration of recombinant 
DNA research. 
I therefore want to voice my support for the revision of the 
guidelines currently proposed. 
Thank you. 
<June E. Osborn, M. D. 
Professor of Medical Microbiology 
and Pediatrics 
Associate Dean of the Graduate School 
(Biological Sciences) 
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