PRODUCTION OF B-CELL DIFFERENTIATION FACTORS BY MOUSE PARENCHYMAL LIVER-CELLS

Previously we reported that most antibody secreting cells secreted IgA in the liver, Here we assessed the possibility that parenchymal liver cells (PLC) produced factors, transforming growth factor (TGF)-beta a nd IL-5, which participate in the differentiation of B cells to IgA-se creting cells. We showed that TGF-beta activity was present in the cul ture supernatant of PLC, and IL-5 activity was in the lysate of PLC. M oreover, it was confirmed that IL-5 protein produced by PLC was mainly localized in the cell membrane by histochemical staining. The finding s that both TGF-beta and IL-5 were produced by PLC should provide usef ul information concerning the fact that IgA-secreting cells were domin ant in the liver.