Anaphylactic Detoxication of Specific Proteins. ∗

Abstract

In the preceding paper 1 we report evidence that marked chemical alterations take place in specific foreign proteins on injection into the animal body, and that certain important immunological adaptations are due to these altered or denaturized proteins, rather than to the primary proteins originally injected. We have obtained further evidence in support of this by a study of the altered anaphylactic toxicity of specific foreign proteins on intravenous injection into normal, hypersensitive and immune dogs.

Measured quantities of horse serum were injected intravenously into these animals, and at varying intervals after this injection quantitative blood transfusions were made into partially exsanguinated anaphylactic recipients. The following is a summary of our results to date:

(1) Normal Dogs. Quantitative transfusions into anaphylactic recipients at any time within 6 hours after intravenous injection of 2 cc. horse serum per kg. of body weight into normal dogs invariably show the circulating blood to have a greater anaphylactic toxicity than that of control amounts of unaltered horse serum. This increase suggests the possibility that the initial change in the injected horse serum in normal dogs is an increase in the number of specific protein molecules by hydrolysis or colloidal dispersion, though other explanations of this increased toxicity are of course possible.

Transfusions at the end of 24 hours show a toxicity approximately equal to that of the control horse serum dose. A slight reduction in toxicity is noted by the end of 48 hours. A toxicity equal to about a quarter of the control dose is noted at the end of 3 days. There is no recognizable anaphylactic toxicity at the end of 4 days.

Quantitative titrations with rabbit precipitin show that there is little or no reduction in the amount of circulating horse protein in the injected normal dog at the end of 4 days.