MIXED AGGLUTINATION WITH TISSUE SECTIONS.

The mixed agglutination procedure was applied to tissue sections. Microtome sections of bovine tissue were placed on coverglasses, fixed by acetone or formalin, and incubated with various dilutions of rabbit antisera. The binding of antibodies to the tissue sections was detected by the addition of an indicator system composed of sheep erythrocytes sensitized by subagglutinating doses of the corresponding rabbit antiserum, and agglutinated by goat antiserum to rabbit serum. In positive reactions the indicator cells covered the tissue, whereas in negative tests, the erythrocytes detached and the tissue appeared uncovered. It was demonstrated that the method is capable of detecting both saline-extractable and saline-non-extractable antigens. In addition to species-specific antigens, organ-specific antigens of adrenal and brain were detected. The method was characterized by a very high sensitivity in detecting antibodies. Its possible application as a tool for investigations on tissue antigens and antibodies was discussed.