The rate of fixation of complement at various temperatures

Abstract

This investigation embraces three types of complement-fixing substances: (1) those elicited in rabbits due to injection of purified proteins; (2) those produced in the same animals due to injection of bacteria, and (3) those found in the serum of syphilitic patients. The antigens employed in the first two cases were specific, while in the case of the syphilitic sera, non-specific; four different Wassermann antigens being employed with each serum. Three fixation temperatures—water-bath, room and ice-box—were resorted to. Some phases of this investigation are still in progress and in this preliminary report, the work with the purified proteins only will be reported, although our findings indicate that the rate of fixation of complement is the same, no matter what type of fixing antibody is used.

Two purified proteins were employed: Edestin obtained from hempseed and phaseolin obtained from the kidney bean. These were kindly furnished by Dr. Thomas B. Osborne. Two rabbits were immunized with edestin and two with phaseolin. In order to elicit quantitative differences in the antibody production in the rabbits, four modes of immunization were resorted to. The edestin rabbits were injected intravenously according to “Immunization Methods No. I and No. 2,” respectively, described by Kahn and McNeil in another paper. 1 The phaseolin rabbits were injected intraperitoneally. One rabbit received 100, 150, 200, 250 and 300 mgm. of phaseolin at 24-hour intervals, and the other 100, 150 and 200 mgm. of this protein at 24-hour intervals.

The complement fixation experiments were carried out in one tenth quantities of regular Wassermanns, otherwise in the usual manner, with 2 units of complement, 2 units of amboceptor and 0.1 C.C. of a standard 5 per cent. suspension of sheep-cells. The respective antigens were prepared by weighing out 10 mgm. of the protein and dissolving these in 10 C.C. of N/1000 NaOH to which was added 0.05 C.C. of N/IO NaOH.