Abstract
Immunosuppressive factor(s) in sera of six children with minimal change nephrotic syndrome (MCNS) were studied. (1) Phosphatidylinositol (PI) and DNA synthesis of peripheral blood mononuclear cells (PBMs) of healthy donor activated by lipopolysaccharide (LPS), Staphylococcus aureus Cowan I strain (SAC) or pokeweed mitogen (PWM) were suppressed by the sera of MCNS. Those suppressive activities were contained in the fraction of lipoproteindeficient serum (LPDS : d>1.25). (2) PI and DNA synthesis of PWM-activated T or non-T cells were also suppressed by sera of MCNS, especially by LPDS fraction. (3) Sterol biosynthesis of PBMs activated by LPS, SAC or PWM were suppressed by sera of MCNS. However, LPDS fraction of MCNS could not suppress the sterol biosynthesis. (4) The differentiation of B cells to IgM-secreting cells by PWM were suppressed by sera of MCNS and the suppressive activity was contained in the fraction of LPDS. However, it was not cleared whether the LPDS fraction of MCNS suppressed B cell differentiation itself or suppressed it secondly by suppressing the prolif erations of T or B cells.
