Identity of Precipitin and Complement Fixing Substances in Syphilitic Sera. I.

Abstract

Whether or not different types of antibodies are identical is still one of the classical questions in immunology. In this country, Zinsser 1 is the outstanding champion of the “unitarian” hypothesis. The identity of precipitins and complement fixing substances in syphilitic sera is being championed in Germany, especially by Jacobstahl. 2 He was the first to show that the precipitate produced by extract antigen and syphilitic serum possesses the property of fixing complement, while the supernatant fluid remaining after removal of the precipitate lacks this complement fixing property.

The question of the identity of complement fixing and precipitin substances in syphilitic serum has recently been indirectly revived through the efforts of several workers to evolve a combined precipitation—complement fixation method in syphilis. Thus, in the case of the Sachs-Georgi test, Kafka, 3 Keining 4 and others have attempted to add complement to the resulting precipitate of this test and carry out a complement fixation reaction. The results, however, have been variable, due undoubtedly to the technical nature of the Sachs-Georgi reaction and the prolonged incubation which it requires.

It was believed that the Kahn test5 might be suitable for the study of the identity of precipitin and complement fixing substances in syphilitic sera. This test gives immediate precipitation reactions on mixing serum with antigen. By adding the hemolytic system to the serum antigen mixture of the completed test, it was believed that immediate complement fixation reactions might also be obtained. If the complement-fixing and precipitin substances are identical, there should be parallelism between the complement fixation and precipitation results. If not identical, little or no parallelism should exist.

Procedure of combined precipitation-complement fixation test: Kahn tests were performed with syphilitic and non-syphilitic sera in the regular manner.