Do Foreign Proteins Multiply in the Animal Body?

Abstract

If 2 cc. horse serum per kilo of body weight are injected subcutaneously, in minute divided doses, into a normal dog, and, if the absorption of the injected horse proteins into the canine circulation is followed by quantitative tests with rabbit precipitin, data are obtained that suggest a 100% absorption of the injected horse proteins into the blood stream by the end of 4 to 7 days, rising to a 200%, or even a 400% absorption by the 14th to 21st day. A 200% horse protein assay of the blood alone might well mean a 1000% or even 2000% alien protein content of the body as a whole.

This does not necessarily mean that the injected horse proteins multiply as a living virus in canine tissues, a biochemical metaphor thus far suggested solely for the bacteriophage. Among the conceivable alternate explanations are: (a) apparent multiplications due to hydrolysis or colloidal dispersion of the injected horse proteins, (b) the formation of pseudo-horse proteins as a result of denaturization of the body proteins of the injected dog, (c) the synthesis or liberation of antibodies of approximate horse protein specificity, and (d) toxic increases in some hypothetical non-specific precipitin reaction.

This paper represents selected data from over 50 experimental and control dogs.