Inhibition of experimental autoimmune myasthenia gravis by MHC class II binding competition peptides

150

P07.01 DETECTION O F IMMUNOREGULATORY B i l l AND IL-10 IN HUMAN ADULT M I C R O G L I A Kenneth Williams,t lining_ Uivestad, ~ and Montreal Neurolegleal ] [ ] ~ t ~ t ~ , I T h e ~ I n t ~ _ e t i o n - We ~ _ e x p r e ~ _ 'gn of B7 Ag(S) ~ IL-10 by human adult microglia and ~ interaction with T cells. Materials and lVldlmds - BT/BB-1 Ag expression was a~_tu~d in dissociated adult human gliM cell cultures using immunofluorescence and on froz¢~ sections from MS and control brains by immunocytochemistry. IL-10 production by microglia in vitro was assessed using RT-PCR and an IL-10 ELISA. An anti-BBl mAb, a CTLA-4 Ig fusion lm3te~, and rIL-10 and an anti-IL-10 Ab were used to assess B7 and IL-10 regulation ofT-cell responses. Results - Microgi/a but not astrocytes were B7/BB-l-positive in ~itro. Mioroggta in select MS brain lmions w e ~ also BT/BB-1positive. Microglia were positive for IL-10 mRNA and produced IL-10 following ~ ~mulation. Anti-B7 Abs ~ d rIL-10 inhibited Ag presentation by microgLia in primary and secondary cell responses. Anti-IL-10 mAb augmented such responses. Conclusion - B7 Ags and IL-10 provide poteatial mechanisms for microglia to serve as immune regulatory cells within the CNS.

P09.01

MONOCLONAL ANTIBODY (MAB) TO A COMPLEMENTARY PEPTIDE FOR TORPEDO ACETYLCHOLINE RECEPTOR (ACHR) RESIDUI~61-76 RECOGNIZES IDIOTYPE ANTIBODIES (ID-ABS): POSSIBLE UTILITY IN MYASTHENIA GRAVIS (MG) S. Ara~a 1, S.J. Oh 2, K. Takahashi 1, J.E Blalock 3 1 Division of Neurology, Institute of Neurological Sciences, Tottori University, Yonago, Japan. 2 Department of Neurology and 3 D e p a r t m e n t of Physiology a n d Biophysics, University of A l a b a m a at Birmingham, AL, USA. We h a v e p r e v i o u s l y r e p o r t e d that i m m u n i z a t i o n with c o m p l e m e n t a r y peptide (denoted RhCA 67-16) for Torpedo AChR 61-76 induces the formation of anti-ld Abs a n d protects against the d e v e l o p m e n t of e x p e r i m e n t a l a u t o i m m u n e MG (EAMG). A mAb to RhCA 67-16 (denoted TCM 240, IgG1, K) also r e c o g n i z e d the c o m b i n i n g sites of three mAbs which were p r e v i o u s l y r e p o r t e d by others to recognize the m a i n i m m u n o g e n i c region of the AChR a n d to cause EAMG. UsIng this mAb TCM 240, we analyzed sera of patients with MG b y ELISA. Serum samples (n=96) from MG patients showed h i g h e r titers (245+288), w h e n c o m p a r e d with ten n o r m a l controls (93+34). TCM 240 also detected significantly h i g h e r Id-abs in 63.696 of the sera from seronegative MG patients. These results suggest novel diagnostic a n d p e r h a p s t h e r a p e u t i c p r o c e d u r e s for MG t h r o u g h the i n d u c t i o n of anti-ld Abs by c o m p l e m e n t a r y p e p t i d e immunogens.

P08.02

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P09.03 ]NnnmmoN OF gXPmUMSNTAL AUTOm~UNe MYAST~NIA GRAVIS BY MHC C ~ H II~qD][NG~ ]N~'YIDI~ M.H.M. Waub~n~, Y.M.F. Orsus~, A.C.W.~. ~ , J.P.A. Wsgmmm'Hilbe~, W. van Iklemzu d M.H. De B m ~ ~UnDersRy o~ Uwecbl, Insflo~ of I ~ DLveases & Immunolosy. P.O. Box 80.16~,35087D Pu,ec&, T~e N m k ~ 4 m ~ . a U ~ y of l,~nbau~, Depa~onent o/ Im,'mmolosy, p.o. Box 616, 6200MD Maoatrkbt, The Netherlands. Inn~vearlon in eq~mueeml aumkemmme d b m m m b,l ,~ u~e of bil.IC b~ndin8

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P09.02 STRIATIONAL AUTOANTIBODIES IN MYASTENIA GRAVIS MODULATE CALCIUM-INDUCED CALCIUM RELEASE FROM SARCOPLASMIC RETICULUM

W01.01 GENETIC ANALY~S OF SUSCEIPrmlIIJTY TO EAE IN MICE

T Asaka. N lshisalm,K Iwasa and M Takamori Departments of Neurology and Biophysics, Kanazawa University School of Medicine,Kanazawa,Japan

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lntroductiou: Recently Mygland et al. reported that some patients of myasthenia gravis (MG) with thymoma have ryanodinc receptor (RyR) autoandbodles. We examined the effect of striational autoantthodies (StrAb) on calcium-indncedcalcium release (CICR) from sascoplasmicrettculum (SR) using calciumindicatorFura-2. Materials and Metheds: Serum samples were taken from 7 MG patients with thymoma and 10 without thymoma. Serum samples from MG patients with thymomahad and-acetylcholinereceptorautoantibodies(AChRAb)and StrAb, but samples from MG without thymoma had AChRAb only. RD cells, which were derived fromrhabdomyoma,were incubatedwith the serum and CICR was induced by external appticufionof mlllimolarcuff~ne. Results: Five of seven serum samples with StrAb and AChRAb blocked the caffeine-indncedCICR. On the otherhand, transient intracellolarcalcium rise was observed after incubation with serum having AChRAb only and with normal control serum. StrAb itself had no flmctionto release calcium from SR. Concluslea: These findings suggest that StrAb goes through the cell membrane and blocks ryanodtne receptor. StrAb may play a rule in the pathophysiologyof myasthonia gruvis through the modulation of excitation-contruclloncoupling by C1CR.

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