ISOLATION AND CHARACTERIZATION OF IMMUNOREGULATORY FACTORS FROM NORMAL HUMAN-SERUM .1. PRELIMINARY BIOCHEMICAL AND BIOLOGICAL CHARACTERIZATION OF IMMUNOSUPPRESSIVE FACTORS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 118  (2) , 505-513
Abstract
Normal human serum inhibited the mitogenic effects of bacterial [Escherichia coli] lipopolysaccharide and Con A [concanavalin A] on mouse spleen lymphocytes and reduced the in vitro antibody response to SRBC [sheep red blood cells] by these cells. Immune suppression occurred without loss of lymphocyte viability. Fractionation of normal human serum resulted in isolation of several immunoenhancing and immunoinhibitory fractions. Electrophoretic analysis of the immunoinhibitory fractions revealed a complex array of serum proteins. The most prominent proteins on polyacrylamide electrophoresis stained for proteins and carbohydrate. The heterogeneity of immunoinhibitory fractions were further substantiated by their differential susceptibility to trypsin, periodate and 2-mercaptoethanol treatment. Heterogeneity of the fractions was related to difference in their biologic activity as expressed in their effects on mitogenicity and immunogenicity of LPS in mouse splenic cultures. Normal human serum apparently contains several immunoregulatory factors with differing biochemical characteristics and cellular sites of action.