Selective inhibition of DNA synthesis by a protein released from spleen cells

Abstract

Spleen cells cultured release proteins into the culture medium, some of which shows both binding activity to single stranded DNA (ss-DNA) and inhibitory activity to 3H-thymidine incorporation into cells. The inhibitory protein of DNA synthesis was purified to near homogeneity by ammonium sulfate precipitation, ss-DNA-cellulose affinity chromatography, and gel filtration chromatography. The molecular weight of the major band of this protein, as estimated by sodium dodecyl-sulfate gel electrophoresis, was approximately 14,000. The effect of the protein was compared with various cell lines and primary cell culture, and it was found that the protein strongly inhibited DNA synthesis of HeLa, L, and HEp2 cells, but only inhibited to a minor extent synthesis of Ehrlich cells and primary culture of mouse embryo.

The influence of spleen size on liver regeneration after major hepatectomy in normal and early cirrhotic liver

“…Does the regeneration capacity of cirrhotic liver decrease? During liver regeneration, a protein released from the spleen cells has an inhibitory effect on the DNA synthesis of liver cells (9). In splenectomized rat, the liver regeneration increases after hepatectomy, suggesting that the inhibitory protein is present in the spleen (10, 24).…”

“…As the disease progress, the size of the liver decrease while the size of the spleen increases. Previous studies have suggested that humoral factors in the normal spleen could suppress regeneration of residual liver after hepatectomy (8–10). Furthermore, hepatectomy in chronic liver diseases can induce significant hypersplenism (11).…”