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 α-dinitrophenyl-poly-L-lysine (α-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.