Isolation and partial characterization of "trace" proteins and immunoglobulin G from cerebrospinal fluid.

Human cerebrospinal fluid investigated byimmunoelectrophoresis with an antiserum against human cerebrospinal fluid has been shown to contain two proteins, which cannot be demonstrated in human serum (Clausen, 1961; MacPherson and Cosgrove, 1961; Hochwald and Thorbecke, 1962). These proteins will here be named fl-trace protein and y-trace protein according to Hochwald and Thorbecke (1962). Other investigators have found, however, from none to nine different precipitation arcs present in cerebrospinal fluid but not in serum when using the same technique (Dencker and Swahn, 1962; Dencker, 1963; Laterre and Heremans, 1963; Laterre, Heremans, and Carbonara, 1964). Because of the different results reported in the literature as regards the immunoelectrophoretic demonstration of proteins in human cerebrospinal fluid not observable in serum, the real existence of such proteins has to be doubted until they have been isolated and characterized in other ways than with immunoelectrophoresis only. Tourtellotte, Parker, and Haerer (1964), as well as Caspary (1965), have used anion exchange chromatography in order to isolate immunoglobulin G (7S y-globulin, IgG) from cerebrospinal fluid. However, these authors have not tested the fractions obtained for the presence of fl-trace protein and y-trace protein. As will be shown here the IgG fraction is always contaminated with the trace proteins after isolation by ion exchange chromatography on D.E.A.E.-cellulose. The present work confirms the finding of fl-trace protein and y-trace protein in human cerebrospinal fluid. In addition an isolation procedure for these proteins and for IgG from cerebrospinal fluid is described.