Immunosuppression by embryonic liver cells.

Liver cells from embryonic and newborn mice were found to interfere with mixed lymphocyte culture (MLC) reactions measuring either cytotoxicity by 51Cr release from target cells or 3H-thymidine incorporation. In both experimental systems a suppression was noted when the stimulator cells were syngeneic or unrelated to the liver donor. In addition, 18-day embryonic and neonatal liver cells were found to interfere with production of antibodies to alpha-dinitrophenyl-poly-L-lysine (alpha-DNP-PLL) in vitro. These findings conform with the hypothesis that embryonic cells can actively suppress immune reactions and thereby prevent a possible response to self.