Effect of recombinant human transforming growth factor β1 on immune responses in patients with chronic hepatitis B

— Studies were undertaken to examine the effect of recombinant human transforming growth factor beta 1 (rTGF-β1) on cellular and humoral immune responses of peripheral blood mononuclear cells (PBMC) from patients with chronic hepatitis B. The addition of TGF-β1 caused a significant dose-dependent inhibition of hepatitis B (HB) core Ag-stimulated interferon-γ and antibody to HB core Ag production and proliferation of PBMC from chronic hepatitis patients and HB-immune donors. TGF-β1 also induced a significant reduction in pokeweed mitogen-stimulated IgG and IgM production, as well as phytohemagglutinin p-stimulated proliferative response of PBMC. The degree of inhibition of TGF-β1 did not differ between antigen-specific and -nonspecific cellular and humoral immune responses, and between control individuals and patients. Pretreatment study with TGF-β1 showed that the activities of T cells, B cells and monocytes were similarly inhibited. Further, TGF-β1 inhibited activities of HLA class I antigen-matched cytotoxic T cells from patients with chronic hepatitis B for HBV DNA-transfected HepG2 cells in a 51Cr release assay. The results suggest that TGF-β1 may play a role in the regulation of antigen-dependent and -independent immune responses in patients with chronic hepatitis B.