BACKGROUND: A human B-cell subpopulation which is identifiable by the expression of cell surface antigen Leu-1 (CD5) is known to be responsive for the antoantibody secretion. The exprimental autoimmune myasthenia gravis(EAMG) could be induced in animals by injecting AChR from electric eel and had the same clinical and pathophysiological characteristics with human myasthenia gravis(MG). The authors performed the study to compare the frequncy of CD5 positive B-lymphocytes in EAMGs with those in human MGs and to understand whether the EAMG showed the similar immunological feature as in human MG. METHOD: For EAMG the 50ug AChR from Torpedo Marmorata with Freund's adjuvant were injected to Lewis rats of 150-200mg three times. The CD5 positive B-lymphocytes from peripheral blood were double stained by the monoclonal PE conjugated anti-CD5 and FITC conjugated anti-rat CD45 antibodies in the EAMGs and by the PE conjugated ani-Leu-11(CD5) and FITC conjugated anti-human Leu-12(CD19) antibodies in human MGs. The expression of positive CD5 positive B-lymphocytes were calculated by the fluorescent activated cell sorter(FACS). RESULTS: The mean CD5 positive B-lymphocytes expression in four EAMGs was 15.05% with ranging from 10.2% to 20,0%, which was increased compared with those in control rats. The mean frequency of CD5 positive B-lymphocytes were 25.2+/-15.05% in human MG(N=25) and 16.0+/-13.5% in normal controls (N=20) respectively, which did not show any significant difference (P=0.08). However the expression of CD5 positive B-lymphocytes in human MGs was significantly correlated with the titer of anti-AChR antibody (P=0.04). CONCLUSION: The increased expression of CD5 positive B-lymphocytes might be associated with the EAMG pathomechansms, but their expression only showed possible correlation with the anti-AchR antibody titer with minimal role in pathogenetic process of human MG. Therefore it would be suggested that immunological process of EAMG (acute form of MG) be a little different from that of human MG, chronic form.
Animals ; Antibodies ; Antigens, Surface ; B-Lymphocytes* ; Electrophorus ; Fluorescein-5-isothiocyanate ; Freund's Adjuvant ; Humans* ; Myasthenia Gravis* ; Rats ; Torpedo

Myasthenia gravis is one of the typical organ specific autoimmune disease and the CD5+ B-lymphocytes are known to be associated with the secretion of autoimmune antibodies. The authors performed the study to establish an animal model of experimental autoimmune myasthenia gravis (EAMG) by immunizing the nicotinic acetylcholine receptor (AChR) and to understand CD5+ B-lymphocyte changes in peripheral blood of EAMGs. Lewis rats weighing 150-200 g were injected subcutaneously three times with 50 microg AChR purified from the electric organ of Torpedo marmorata and Freund's adjuvant. The EAMG induction was assessed by evaluating clinical manifestations. The CD5+ B-lymphocyte was double stained using monoclonal PE conjugated anti-CD5+ and FITC conjugated anti-rat CD45R antibodies and calculated using a fluorescence-activated cell sorter (FACS). In three out of ten Lewis rats injected with purified AChR, the EAMG models were established. The animals showed definite clinical weakness responded to neostigmine; they had difficulty in climbing the slope, or easily fell down from a vertical cage. The range of CD5+ B-lymphocytes of peripheral blood in the EAMG models was 10.2%-17.5%, which was higher than in controls. In conclusion, the EAMG models were successfully established and the CD5+ B-lymphocyte expression in peripheral blood increased in EAMGs. This provided indirect evidence of the autoimmune pathomechanism of human myasthenia gravis.
Animal ; Antigens, CD5/immunology* ; B-Lymphocytes/immunology* ; Disease Models, Animal ; Myasthenia Gravis/immunology* ; Myasthenia Gravis/chemically induced ; Rats ; Rats, Inbred Lew