Further studies in serum sickness

Abstract

In a previous paper, 1 I showed by anaphylactic methods that the blood of human beings who had received large injections of therapeutic horse serum contained not only horse serum, but antibodies thereto, at some stage of the serum sickness. Since that time I have approached the same problem by means of the precipitation method, which is very much the more delicate method for the purpose. Remnants of horse serum in the blood are demonstrated by precipitation with the serum of a rabbit immunized to horse serum. Antibodies to horse serum are demonstrated by precipitation of horse serum by the human serum. By this method it has been possible to demonstrate the presence of horse serum in the blood from the time of injection up to more than twenty-one days thereafter, in constantly diminishing amount. Antibody is, as a rule, demonstrable within seven to ten days after the therapeutic injection, and in increasing amounts thereafter, for at least two to three weeks. As a rule, antibody can be demonstrated either at the onset of the serum sickness or within one or two days thereafter. Thus, these two factors coexist in the blood throughout the serum sickness, and even for some days after its subsidence.

The bearing of these facts upon the interpretation of serum sickness is not easy to determine. In the first place, it is not probable that the coexisting antigen and antibody correspond to one another; in all likelihood they represent different fractions of the complex antigen, namely horse serum. According to present conceptions, the antigen is progressively neutralized by the antibody, both of the cells and of the circulating blood. Reasoning by analogy, this neutralization, when it takes place within the blood, produces no symptoms of any kind.