Effect of the removal of lipids on specific precipitation.

Horse antisera to rabbit albumin and globulins and to Type III pneumococci were extracted at low temperatures with alcohol-ether. The precipitin reactions given by these sera deprived of lipids were studied by quantitative analytical methods. With longer periods of standing and slightly higher speeds of centrifugation than those usually required for lipid-containing sera, precipitation may be made complete in immune sera from which the lipids have been removed. The function of lipids in immune reactions is discussed, as well as the effects on antibody globulin of the procedures used in their removal.