EXTRACTION AND PURIFICATION OF ACTIVE IGG FROM SSPE AND MS BRAIN

Immunoglobulin (Ig) G was purified from soluble and membrane fractions of postmortem subacute sclerosing panencephalitis (SSPE) brain, multi ple sclerosis (MS) brain plaque-periplaque white matter, and normal hu man brain (NHB) white matter. After homogenization in 0.32 M sucrose a nd removal of cell debris and nuclei by low-speed centrifugation, solu ble and crude membrane fractions were separated by ultracentrifugation . After removal of sucrose by dialysis, IgG was isolated from the solu ble fraction by protein A affinity chromatography. IgG was obtained fr om the membrane fraction by elution at low pH and purification from th e eluate by protein A chromatography. Whereas very little IgG was in N HB white matter, significant levels of IgG were recovered from both SS PE and MS brain. Both immunocytochemical staining of measles virus-inf ected cells in tissue culture and protein immunoblotting of virus-infe cted cell lysates showed that the IgG from SSPE brain contained activi ty specific for measles virus protein. The abundance, purity and funct ional activity of IgG extracted from SSPE and MS brain indicate that I gG extracted from the brain of humans with an inflammatory disease of unknown etiology can be used to identify its corresponding antigen. (C ) 1997 Elsevier Science B.V.