Gel-precipitating measles virus antibodies in subacute sclerosing panencephalitis: relation to oligoclonal IgG proteins in the cerebrospinal fluid and serum, and the occurrence of two separate fractions of antibody to virus nucleocapsids.

Two to five separate gel-precipitating (GP) antibody activities to sonicated measles virus cell pack antigen were detected by double immunodiffusion and immunoelectrophoresis of sera and cerebrospinal fluids (CSF) from patients with subacute sclerosing panencephalitis (SSPE). The major GP activity was identified as antibody to measles virus nucleocapsids, and a weaker activity as antibody to the virus haemagglutinin. The specificities of the other activities were not determined. Evidence is presented that measles GP antibody activities of both serum and CSF from patients with SSPE are carried by IgG proteins of restricted heterogeneity. Two separate and differently charged homogeneous IgG proteins with antibody activities to partially different measles nucleocapsid antigens were detected in about half the patients. The combined use of agarose electrophoresis and measles GP antibody immunoelectrophoresis of serum and CSF proved helpful in establishing rapidly the specific diagnosis of SSPE.