[Specific substances of the thymus reacting with thymus-dependant antigens].

A fraction was isolated from the sulphate extract of rats and calfs thymus. This fraction reacts with sheep erythrocytes and rabbits IgG in the agglutination test. An identical fraction from the rats spleen and liver is not active in the same concentration. Active substance was purified by affinity chromatography on IgG cellulose column. The absorption spectrum of the purified substance in 220-300 nm region was studied at pH 7. This substance has not the absorption maxima in 280 nm. The sedimentation constant of the crude preparation is approximately 1.7 s. It supposed, that this substance is a specifical receptor of thymic cells.