Immunochemical and Electrophoretic Properties of Oestrous Rabbit Uterine Fluid Proteins Obtained by Uterine Ligation

Summary. Fluids were obtained from 185 rabbit uteri 1 to 20 weeks after uterine ligation. The uterine fluid proteins were concentrated with an ultrafilter and characterized by diffusion in agar gel, moving boundary electrophoresis, and immunoelectrophoresis. Eight electrophoretic components were identified by means of moving boundary electrophoresis. One which migrated as a pre-albumin and another which migrated as an alpha-globulin were not found in blood sera. Agar-gel diffusion tests revealed thirteen antigenic components in uterine fluid. Three precipitin lines appeared to be specific to uterine fluid after absorption of guinea-pig antisera to rabbit uterine fluid with rabbit blood sera. However, at least five antigens which could not be found in blood sera were identified in uterine fluid by means of immunoelectrophoresis. The mobilities of two were similar to prealbumins and the mobilities of the remaining three were similar to beta-globulins. The results indicated that at least two classes of proteins, which do not exist in rabbit blood serum, may be found in uterine fluids obtained by ligation.