Abstract
The cross-reactivity of antibovine alkaline ribonuclease (RNase) rabbit antiserum or antibovine acid RNase rabbit antiserum with heterologous alkaline or acid RNase was studied immunochemically and immunohistochemically. Immunochemical cross-reactivity was determined quantitatively by the inhibitory effect of antiserum on enzyme activity of appropriate RNase from various sources, human, rat, etc. Antibovine alkaline RNase antiserum strongly inhibited the alkaline RNase activity of human, rabbit, rat, mouse or guinea pig liver. On the other hand, antibovine acid RNase antiserum inhibited the acid RNase activity of human, rat or mouse spleen only moderately. Sections from human, rabbit, rat, mouse or guinea pig pancreas and spleen were stained with either fluorescein-labeled antialkaline RNase or antiacid RNase antibody. Fluorescent staining results confirmed the results of the inhibitory effect, and the patterns were essentially identical with those observed in bovine pancreas or spleen, except in the islets of Langerhans in the rabbit pancreas, in which some substances in the cytoplasm of the α cells were observed to react with either rabbit γ-globulin or guinea pig γ-globulin; this reaction was diminished by the procedure of paraffin embedding.