Journal ofNauroimmunology, 5 (1983)251-259 7.$1 Elsevier or~100155 Flow Microfluorometry Detects IgM Autoantibody to Oligodendrocytes in Multiple Sclerosis J.S. Pedersen, M. Walker, B,H, Toh, H.J. De Aizpurua, SJ. Lolait and C.C.A. Bernard * Dtp~tmem of Patholosyand ]nmumolo~,, Monash Unwersity MedicalScho~ Conunercial l¢o~ Praimm, Victoria 3181 (Australia) (Re~ived24 March,1983) (Revised, received 23 May, 1983) (A~'pted 14June,1983) Summary Freshly isolated canine oli8odendrocytes were reacted by indirect membrane immun0fluorescence with 44 sera from patients with multiple sclerosis (M~q). Using analysis by flow microfluorometry (FMF), we found significant IBM antibody binding to the surfaces of oli8odendroc~ in the MS sera. The fluorescence intensity of cell surface reactions for MS sera (F.I. > 40= 37.2 + 21.34~) was significantly different (P < 0.001) to that fcr 53 sera from norn~d subjects (10.0 + 8.975), 15 sera from patients with Murray Valley encephalitis (6.18 + 5.35), 22 with brain tumours (6.18 + 5.3~), 25 with SLE (13.42 + 11.65~), 7 with GBS (9.77 ± 3.9~) and 7 miscellaneous neurological disorders (6.87 + 3.04%). Cell surface bindins was restricted to olisodendrocytes and was absorbed out by oli8odendrocytes but not by liver cells or kidney cells. Oli8odcmdrocytes were identified by conventional histol- oKV, p ~ n t r a s t optics, electron microscopy (EM) and by cell surface reactions with anti-salactocerebroside, a sw~ific i_mmunocytological marker for cytes. A cell sort of the sinsle 0° FMFscatter peak followed by EM e~aminatkm confirmed that the reactive cells consisted exclusively of oli8odendrocytes. Viability of oli8odendrocytes before and after the staining reactions, was > 80~ as ~se,~d by trypanblue and fluorescein diacetate exclusion. The possfl:,ility that immne~ reactions mediated by the surface-reactive antibody with readily ___~cem_ "ble cell work v'u supported by the Australian Neurologkal Foundation, the Nsticaal HetP.k mad Mediad Reum~n Council of Australia (lqH and MRC} and the Natkmal Mtt~tiple Sdemm d Aaa~lia. C.C.A.~mun'dis a SmiorR e ~ Fellow of the NH and lt4~tC of AustraliL * N~olmmtmetol~ l ~ t o ~ , . La TmbeUt~venity, Victoria, Australia. 0165.5728/83/$03.00 © 1983~ Science PublishersB.V.