Abstract
Summary: By injecting rabbits with kidney suspensions from mice of different strains it is possible to obtain strain-specific immune sera. The strain-specificity may be demonstrated by agglutination of tanned erythrocytes which have been coated with soluble kidney components. The strain-specific antigens studied are water-soluble and probably proteins. They are present not only in kidney, but also in lung, liver, spleen and white cells. Testis and brain are poorer sources of these antigens and mouse erythrocytes and serum appear to be deficient in these substances. The strain-specific tissue antigens are thought to be distinct from blood group substances of mice.