The Development of a Plasma Volume Expander G3 



precipitable material can be removed by trichloracetic acid precipita- 

 tion."' Peptide and conjugate have been found to be soluble over short 

 periods of time in the trichloracetic acid supernatant. After filtration 

 of the TCA mixture, however, the trichloracetic acid must be extracted 

 immediately with ether, both because it will eventually cause precipi- 

 tation of the peptide and because it forms an insoluble precipitate with 

 safranine. 'With these methods available, excretion rates and blood 

 levels were easily followed. As expected the conjugates were retained 

 in the blood stream much longer than the straight-chain peptides. 



At this interesting juncture it was decided that a "blood substitute" 

 was no longer urgently needed, as the transportation of chilled whole 

 blood to needed areas was practicable on a desirable scale. Further- 

 more, glutamyl peptide had suddenly acquired a new importance. It 

 seemed that the available conventional military, industrial, and scien- 

 tific forces might not suffice to meet the insatiable demands of war. 

 Man, with inhuman ingenuity, successfully met this challenge — some- 

 what to his later consternation. Among the new offerings at the time 

 was that of biological warfare, and the possibility arose that certain 

 knowledge and skills hitherto devoted to the benevolent purposes of 

 the healing art might be perverted to more destructive ends. It there- 

 fore became necessary to prepare defenses not only against the nat- 

 urally occurring epidemic concomitants of war, but also against the 

 possibility of man-made pestilence. The next phase of our work on 

 the peptide was to be under the auspices of Camp Detrick, Maryland, 

 then the center of biological warfare activity. 



The anthrax organism had achieved the high distinction of early 

 consideration as a suitable agent for biological warfare. Glutamyl 

 peptide, as already mentioned, was known to be a capsular component 

 of the anthrax organism and was thought in this capacity to be partly 

 responsible for its virulence. 



On this basis it was reasoned that antibodies to this peptide should 

 confer some degree of protection against infection by the anthrax 

 organism, and the development of a vaccine containing the glutamyl 

 peptide as the specificity-conferring component became desirable. It 

 had long been known that protective antipeptide antibodies were not 

 readily produced by anthrax vaccines prepared in the usual fashions, 

 nor. for that matter, by actual anthrax infection and recovery. It 

 was hoped, therefore, that a more potent, protective vaccine for humans 

 might be prepared by attaching the peptide as a haptene group to 

 human protein. In man this antigen should presumably produce anti- 

 bodies specific for this peptide. 



