Serum cytotoxicity to oligodendrocytes in multiple sclerosis and controls: assessment by 51Cr release assay

In order to quantitate oligodendrocyte cytotoxicity induced by sera from patients with multiple sclerosis (MS) and control sera, we established a 51Cr release assay system using cultured oligodendrocytes as target cells. With this assay system, we detected serum-induced cytotoxicity in isolated oligodendrocytes in sera from patients with MS, other neurological diseases (OND) and normal individuals. Oligodendrocytes were much more susceptible than astrocytes. The serum cytotoxicity was abolished by heating sera at either 56 degrees C or 50 degrees C for 30 min, and disappeared in storage at 23 degrees C for 1 month or at 4 degrees C for 2 months. Addition of fresh guinea pig serum as a source of complement did not restore the cytotoxic effect. Although the serum factor cytotoxic to oligodendrocytes is not specific for sera from patients with MS, it is possible that it may damage oligodendrocytes if the blood-brain barrier is impaired, as occurs in MS.