A study of the serum of complement-deficient guinea pigs

H. D. Moore 1 has described a race of guinea pigs that are naturally deficient in complement: the deficiency is inherited. A number of these animals were obtained from Dr. F. A. Rich of the Vermont State Agricultural Experiment Station and the sera of four were separately examined as to the presence of the components of complement. The findings were identical in all of the sera.

Both the mid-piece and the end-piece of complement are present. There is lacking only the so-called “third-piece,” which is the thermostable element of complement that is destroyed by cobra-venom and absorbed by yeast cells and bacteria.

By itself, the complement-deficient serum produces no hemolysis when used in a quantity 40 times that of the minimal completely heomlytic quantity of normal serum. When mixed with a small quantity of inactivated normal serum (guinea pig or human) the complement-deficient serum hemolyses in about three times the minimal hemolytic quantity of normal guinea pig's serum.

The third piece of complement is not identical with the lipoid cytozyme (thrombokinase), since the blood of the complementdeficient guinea pigs clots normally. The third piece of complement is not absorbed out of normal serum by six volumes of ether.