Mechanism of the Positive Cephalin-cholesterol Flocculation Reaction in Hepatitis.

An alteration of the blood serum proteins in patients with catarrhal jaundice has been amply established by the development of a positive cephalin flocculation (1). A standard emulsion composed of cephalin and cholesterol, which remains stable in 0.2 ml. to 0.1 ml. normal serum, diluted 1: 21, tends to flocculate and precipitate when added under identical conditions to the serum of patients with catarrhal jaundice. As the disease subsides, the positive reaction returns to negative. The mechanism of the reaction has not been adequately explained. We have shown in unpublished experiments that a positive reaction is accompanied by the absorption of globulin by the emulsion particles, since rabbits immunized intravenously with washed flocculated material develop precipitins for the globulin components of both the euglobulin and pseudoglobulin fractions of human serum. The intensity of the precipitin reaction is the same with normal serum and with that from hepatitis, indicating that the absorbed protein does not differ antigenically from the globulin of normal serum. The mechanism of the cephalin-cholesterol flocculation reaction has been investigated (2) and it was found that the gamma globulin fraction of the serum was the sole component giving a positive flocculation, and further that there was no difference in the flocculating power of the gamma globulin fraction obtained electrophoretically from a normal serum giving a negative reaction and the gamma globulin obtained from a hepatitis serum giving a strongly positive reaction. It was inferred that the negative flocculation obtained with normal sera was due to the inhibiting action by some other component of the serum. Complete inhibition of the reaction was not obtained with the albumin fraction in the proportions used by these observers, although inhibition of the colloidal gold reaction, which showed many points of similarity, was obtained with electrophoretically separated albumin. The present report is an extention of the studies mentioned above, including the use of gamma globulin and albumin in amounts comparable to those occurring in 0.1 ml. of whole serum.