Toshikazu Shirai

Specificity of mouse hybridoma antibodies to DNA

Utilizing the somatic cell hybridization technique, we established 12 clones of mouse hybridoma from MRL/Mp-lpr/lpr(MRL/1) and NZB X NZW(B/W F1) mice, which produce antibodies reacting mainly with ssDNA (anti-ssDNA) and 2 clones from B/W F1 mice, which produce antibodies reacting with both ssDNA and dsDNA (anti-ss/dsDNA). By means of a competitive inhibition radioimmunoassay with synthetic polynucleotides, the anti-ssDNA antibodies were classified into 5 types, in terms of the DNA base specificity. The anti-ss/dsDNA antibodies had polyspecific reactivity to a wide range of polynucleotides, including synthetic RNA.

IgE Associated nephropathy in a patient with subcutaneous eosinophilic lymphoid granuloma (Kimura's disease)

A patient with subcutaneous eosinophilic lymphoid granuloma (Kimuras disease) associated with a high serum IgE level and a marked blood eosinophilia, had a glomerulonephritis with electron dense deposits in mesangial, paramesangial, subendothelial, intramembranous and epimembranous areas. By immunofluorescence, all the glomeruli showed predominant depositions of IgE and IgG along the paramesangial areas and capillary walls together with complement components. The germinal centers in the lymph follicles formed in both the subcutaneous granuloma and the kidney interstitium also contained mainly IgE and IgG but no complement components. These features of this disease suggest that the glomerular lesion is one of the systemic manifestations of Kimuras disease.

Subpopulation of T Cells Sensitive to Natural Thymocytotoxic Autoantibody (NTA) of New Zealand Mice: I. Distinct Cytotoxic Sensitivity of Functional T Cell Subsets to NTA and Anti‐Thy‐1 Antibodies

NZB mice produce a natural thymocytotoxic autoantibody (NTA) capable of specifically injuring thymocytes and T cells. NTA‐reactive antigen (NTA‐A) shows a different density distribution among T cells, and partial killing with NTA and complement can eliminate T cells bearing NTA‐A in high density. Thy‐1 antigen is similar to NTA‐A in this respect. To determine the effects of NTA and anti‐Thy‐1 on distinct functional subsets of T cells, Con A‐induced suppressor T cell (Con A‐Ts) activity against the allogeneic mixed lymphocyte reaction (MLR), responding T cell (TMLR) activity in the allogeneic MLR, and Con A‐induced cytotoxic T cell (Con A‐Tc) activity were examined simultaneously in BALB/c spleen cells before and after partial elimination of NTA‐ and anti‐Thy‐1‐sensitive T cells. Treatment with NTA and complement resulted in a marked reduction in Con A‐Ts activity, a significant increase in TMLR activity and a slight and inconstant decrease in Con A‐Tc activity. Since Con A‐generated Ts were much less sensitive to NTA, the NTA‐sensitive T cells involved in Con A‐Ts activity appear to be precursors or promoters of the Con A‐Ts. In contrast, the precursors of Con A‐Tc seem to be relatively resistant to NTA. The increase in TMLR activity caused by NTA suggests the possibility that NTA is less cytotoxic for TMLR and cytotoxic for some suppressor T cells in allogeneic MLR. The monoclonal anti‐Thy‐1 antibody showed no such preferential cytotoxic effects on the three T cell functions. The NTA‐sensitive T cells, in contrast to anti‐Thy‐1‐sensitive T cells, were reduced gradually during Con A stimulation. All these findings indicate that NTA‐A not only differs from Thy‐1 antigen but that it appears to be a unique T cell antigen.

ANTI‐ACETYLCHOLINE RECEPTOR ANTIBODIES IN MYASTHENIC SERUM AND THYMUS: THEIR CORRESPONDENCE AND DISCREPANCY WITH CLINICAL CONDITIONS

The author reported the relationship between the titers of antiacetylcholine receptor ( AChR) antibodies, clinical state and findings of single fiber electromyography in a series of myasthenic patients using two theoretically different assay systems in order to elucidate their correspondence and discrepancy with clinical conditions. One hundred and forty-one myasthenic patients out of 210, namely 65%, showed positive result by immunoprecipitation method, assuming that the antibody recognizes antigenic determinants other than toxin binding sites in AChR protein, thus constitutes of “noninhibitory” antibody. We adopted a new classification of patients into familial and non-familial types, the latter being divided into thymoma and nonthymoma groups. In the nonthymoma group the patients were classified into four types; ocular, generalized mild, moderate and severe types. Serial changes of the titers of anti-AChR antibody assayed by immunoprecipitation method showed close and parallel fluctuation associated with clinical changes; namely, yearly decrease after complete thymectomy, monthly decrease during steroid therapy, and abrupt changes during myasthenic crisis. We obtained positive results in 53 out of 70 (73%) myasthenics using the concanavalin A Sepharose method, assuming that the antibody recognizes the neurotoxin binding site and/or sugar chain on AChR. There was more loose correlation of the inhibitory activity of the “inhibitory” antibody with the clinical state, comparing with the case in “noninhibitory” antibody. Comparative and simultaneous assays in 81 myasthenic patients using the immunoprecipitation and concanavalin A method were carried out. In 20 cases of the ocular type, the titers of both antibodies were low comparing with other myasthenic groups. In 16 cases of thymoma, there was a significant correlation at the 5 % level between both antibody titers. On the contrary, in 45 cases of generalized nonthymoma, they were diverse and scattered without significant correlation to each other. These data suggested that there may be different types of immune responses producing heterogeneous anti-AChR antibodies depending upon the types of myasthenia gravis and/or clinical conditions. This could elucidate part of the occasional discrepancies between the antibody titers and clinical symptoms.