Monoclonal antibody to acetylcholine receptor: cell line established from thymus of patient with Myasthenia gravis.

A human B cell line producing a monoclonal antibody to an antigenic determinant of acetylcholine receptors was established by cloning B cells that had been transformed in vitro by Epstein-Barr virus. The B cells were obtained from the thymus of a patient with myasthenia gravis. The antibody produced by the cell line precipitated acetylcholine receptors from denervated and innervated rat muscle and from human muscle, but did not show detectable response to the acetylcholine receptors from the electric organs of Narke japonica. The monoclonal antibody showed identical binding patterns in innervated and denervated rat muscles. Passive transfer of the monoclonal antibody into rats induced moderate muscle weakness and electromyographic changes characteristic of myasthenia gravis.

Multilineage potential of side population cells from human amnion mesenchymal layer.

Side population (SP) cells were isolated by FACS from a human amnion mesenchymal cell (AMC) layer soon after enzyme treatment. The yield of SP cells from AMC layer (AMC-SP cells) was about 0.1-0.2%. AMC-SP cells grew well with cell doublings of 40-80 days of culture. FACS profiles and immunocytostaining showed that AMC-SP cells were composed of two different cells immunologically: HLA I(-)/II(-) and HLA P/II(-). Oct-3/4 was detected in the nucleus of AMC-SP cells, when the culture was examined at the third, sixth, and 10th passages. RT-PCR showed that AMC-SP cells expressed the Oct-4, Sox-2, and Rex-1 genes. Immunocytochemistry revealed that all AMC-SP cells were vimentin+, CK19+, and nestin+. In addition, flow cytometry analysis showed that SP cells had high expression of CD13, CD29, CD44, CD46, CD49b, CD49c, CD49e, CD59, CD140a, and CD166 but low expression of CD 49d, and CD51. No evidence of expression was obtained for CD34, CD45, CD49a, CD56, CD90, CD105, CD106, CD117, CD133, CD271, or Flk-1. Upon appropriate differentiation protocols, AMC-SP cells differentiated to several cell lineages such as neuroectodermal, osteogenic, chondrogenic, and adipogenic cells. These results indicate that AMC-SP cells have multilineage potential to several cell lineages with unique immunological characteristics such as HLA I(-)/II(-) or HLA I+/II(-). AMC-SP cells should be of considerable value for regenerative medicine because they do not induce acute rejection after allotransplantation, they do not cause ethical issues, and there is no limit of supply.

Immunosuppressive factors from mastocytoma cells cultured in serum-free medium.

Immunosuppressive factors were isolated from culture fluids of DBA/2 mouse mastocytoma cells grown in serum-free RPMI-1640 medium by measurement of inhibitory activity on tritiated thymidine uptake of DBA/2 spleen cells responding to Escherichia coli lipopolisaccharide (LPS) and concanavalin A (ConA) and by comparison of the number of hemolytic antibody-forming cells in vitro after simultaneous addition of the factors with sheep red blood cells (SRBC). The culture fluids were separated into four fractions with immunosuppressive activities: F-I (mol wt, > 30,000), and F-II (mol. wt, 10,000-30,000), F-III (mol wt, 2,000-10,000), and F-IV (molwt, 700-2,000), F-IV specifically suppressed lymphocyte responses to E. coli LPS at concentrations of 50-200 microgram/ml. The other three fractions also showed immunosuppressive activities in both Con-A-induced and E. coli LPS-induced lymphocyte responses. The four fractions as well as crude culture fluids of mastocytoma cells expressed as immunosuppressive effect when injected into the peritoneal cavities of DBA/2 mice at doses of 24-180 microgram/day for 5 consecutive days. The fractions with a molecular weight equivalent to F-IV of mastocytoma culture supernatant were detected little, if any, in the supernatant from a nonmalignant cell culture. No suppressive effects of the fraction with a molecular weight greater than 2,000 (equivalent to F-I + F-II + F-III) from nonmalignant cell culture were found on lymphocyte responses to mitogens or SRBC at the concentrations used (100-200 microgram/ml).

Altered immunologic responsiveness in mastocytoma-bearing mice.

Immune responses to sheep erythrocytes were enhanced in mice bearing small mastocytomas soon after injection of a few tumor cells. In contrast, mice with larger tumors after transfer of a greater number of mastocytoma cells and those in the later stages of tumor development after transfer of small numbers of tumor cells showed moderately suppressed immune responses. Transfer of spleen cells from mastocytoma-bearing mice to irradiated recipients resulted in more antibody-forming cells as compared to transfer of splenocytes from normal donor mice. The addition of graded numbers of mastocytoma cells to a constant amount of normal spleen cells transferred to irradiated mice also resulted in enhanced responses and increased spleen weights in the recipients. This increase, in direct proportion to the number of mastocytoma cells transferred, also occurred when Escherichia coli lipopolysaccharide (a T-cell independent antigen) was used to immunize animals given spleen cells from normal mice and mastocytoma cells. Mastocytoma cell-free homogenates or X-irradiated tumor cells also heightened immune responses in recipient mice, which indicated that viable cells were not needed for the effect. Such homogenates, as well as the tumor cells per se, stimulated increased lactate dehydrogenase (LDH) activity in the sera of recipient mice. However, tumor cells passaged in tissue culture for several months, those derived from mice bearing a mastocytoma cell line with a low LDH-stimulatory activity, or UV-irradiated mastocytoma cells with a high LDH-stimulatory activity did not induce enhanced plaque-forming cell responses.

A simplified procedure for in vitro immunization of dispersed spleen cell cultures.

Dispersed spleen cell suspensions from normal mice were immunized with sheep erythrocytes in flat bottom vial tubes containing a relatively small amount of tissue culture medium fortified with a 'nutrient cocktail'. The magnitude of the number of antibody plaque forming cells appearing in such tube cultures was equivalent or greater than that obtained in Marbrook vessels in the Mishell--Dutton system. Omission of the nutrient cocktail on the day of culture initiation, or the use of round bottom vials, resulted in much lower PFC responses.

An enzyme-linked immunosorbent assay for antibodies against saline-soluble muscle components in myasthenia gravis.

An enzyme-linked immunosorbent assay (ELISA) system has been developed for measuring antibodies against rat skeletal muscle components solubilized with phosphate-buffered saline. With this assay, 53.8% (50/93) of sera from patients with myasthenia gravis (MG) was positive (the values over the mean plus 3 SD of 256 healthy individuals were considered significant). No sera from patients with neurological disorders other than MG gave positive values (0%; 0/60). No correlation between titers of antibody against the muscle components and those of anti-acetylcholine receptor antibody (r = 0.01) was found. These results indicate that our ELISA system is useful for diagnosing myasthenia gravis.

Axially chiral 1,7-naphthyridine-6-carboxamide derivatives as orally active tachykinin NK(1) receptor antagonists: synthesis, antagonistic activity, and effects on bladder functions.

Cyclic analogues of N-[3,5-bis(trifluoromethyl)benzyl]-7,8-dihydro-N, 7-dimethyl-5-(4-methylphenyl)-8-oxo-1,7-naphthyridine-6-carboxamide (1) having a 6-9-membered ring (6-9) were synthesized and evaluated for NK(1) antagonistic activities. The 8-membered ring compound with a beta-methyl group at the C((9))-position, (aR,9R)-7-[3, 5-bis(trifluoromethyl)benzyl]-8,9,10, 11-tetrahydro-9-methyl-5-(4-methylphenyl)-7H-[1,4]diazocino[2,1-g] [1, 7]naphthyridine-6,13-dione [(aR,9R)-8b], was atropodiastereoselectively synthesized by cyclization of a chiral intermediate, 10g. On the other hand, the 7-membered ring compound with a beta-methyl group at the C((9))-position [(9S)-7b] was obtained as an equilibrium mixture of atropisomers with a ratio of ca. 3:2 in solution at room temperature (measured by NMR in CDCl(3)). Compounds (9S)-7b and (aR,9R)-8b exhibited excellent antagonistic activities both in vitro [IC(50) (inhibition of [(125)I]BH-SP binding in human IM-9 cells) = 0.28 and 0.45 nM, respectively] and in vivo (iv and po). Significantly, the in vitro activity of (aR, 9R)-8b was ca. 750-fold higher than that of its enantiomer (aS, 9S)-8b, ca. 40-fold higher than its atropisomer (aS,9R)-8b, and ca. 20-fold higher than its diastereomer (aR,9S)-8b. The structure-activity relationships in this series, along with the X-ray analysis of (aR,9R)-8b, indicated that the stereochemistry around the -C((6))(=O)-N((7))-CH(2)Ar moiety is important for NK(1) receptor recognition. The NK(1) antagonists showed effects on bladder functions in guinea pigs upon intravenous injection: i.e., the antagonists increased the shutdown time of distension-induced rhythmic bladder contractions and the bladder volume threshold, and the effects on the shutdown time were found to correlate well with the NK(1) antagonistic activities. Compound (aR,9R)-8b has been identified as a potential clinical candidate for the treatment of bladder function disorders.

Novel, potent, and orally active substance P antagonists: synthesis and antagonist activity of N-benzylcarboxamide derivatives of pyrido[3,4-b]pyridine.

A series of 4-phenylisoquinolone derivatives were synthesized and evaluated for NK1 (substance P) antagonist activity. Highly potent antagonists, 4-phenyl-3-isoquinolone-N-benzylcarboxamides (11), were discovered from the structure-activity relationship studies on the isoquinolone-urea lead 1a. Optimization of the activity in this series resulted in the development of 5-phenyl-6-pyrido[3,4-b]pyridine-N-benzylcarboxamides (30) which are highly potent orally active NK1 antagonists. Among the compounds synthesized, N-[3,5-bis(trifluoromethyl)benzyl]-7,8-dihydro-N,7-dimethyl-8-oxo-5- (substituted phenyl)-6-pyrido[3,4-b]pyridinecarboxamides (30a,f,g) showed excellent antagonist activities with IC50 values (in vitro inhibition of [125I]-BH-SP binding in human IM-9 cells) of 0.21-0.34 nM and ED50 values (in vivo inhibition of capsaicin-induced plasma extravasation in guinea-pig trachea, iv) of 0.017-0.030 mg/kg. These compounds exhibited significantly potent activity upon oral administration with ED50 values of 0.068-0.17 mg/kg. Conformational studies on 30g indicated that the two stable conformers of 30g are quite similar to those of CP-99,994.

Axially chiral N-benzyl-N,7-dimethyl-5-phenyl-1, 7-naphthyridine-6-carboxamide derivatives as tachykinin NK1 receptor antagonists: determination of the absolute stereochemical requirements.

A potent and orally active NK1 antagonist, trans-N-[3, 5-bis(trifluoromethyl)benzyl]-7,8-dihydro-N, 7-dimethyl-5-(4-methylphenyl)-8-oxo-1,7-naphthyridine-6-carboxamide (1t), was shown to exist as a mixture of separable and stable (R)- and (S)-atropisomers (1t-A and 1t-B) originating from the restricted rotation around the -C(6)-C(=O)- bond; the antagonistic activities of 1t-A were ca. 6-13-fold higher than those of 1t-B. Analogues of 1t (3), which have (S)- and (R)-methyl groups at the benzylic methylene portion of 1t, were prepared and separated into the diastereomeric atropisomers, 3a-A, 3a-B and 3b-A, 3b-B, in enantiomerically pure forms. Among the four isomers of 3, the (aR, S)-enantiomer (3a-A) exhibited the most potent antagonistic activities with an IC50 value of 0.80 nM (in vitro inhibition of [125I]BH-SP binding in human IM-9 cells) and ED50 values of 9.3 micrograms/kg (iv) and 67.7 micrograms/kg (po) (in vivo inhibition of capsaicin-induced plasma extravasation in guinea pig trachea), while the activity of the (aS,R)-enantiomer (3b-B) was the weakest with an IC50 value of 620 nM. The structure-activity relationships in this series of antagonists indicate that the (R)-configuration at the axial bond and the stacking (or stacking-like) conformation between the two phenyl rings as shown in 1t-A and 3a-A are essential for high-affinity binding and suggest that the amide moiety functions as a hydrogen bond acceptor in the interaction with the receptor.

Identification of haemopoietic biglycan in hyperplastic thymus associated with myasthenia gravis.

Generally biglycan, a small proteoglycan, has been thought to play a role as an extracellular matrix and/or a reservoir for other factors, such as TGF-beta and collagens. Recently, we have found that a soluble 100 kDa biglycan, produced from the rat thymic myoid cells and the brain glial cells, predominantly stimulates growth and differentiation of monocytic lineage cells from various lymphatic organs, including microglias. In the present study, we attempted to identify biological significance of the corresponding molecules in human, using five myasthenic thymuses (three with hyperplasia and two with thymoma) that had been surgically removed for therapeutic purpose. With immunohistochemistry, many biglycan positive cells were detected in the germinal center of the three hyperplastic thymuses, but not in the two thymuses associated with lymphocytic thymoma. Biglycan purified from the hyperplastic thymuses by an immunoaffinity column was found as a monomer with apparent molecular size of 95-100 kDa and self associated oligomers of greater than 201 kDa. The purified biglycan markedly stimulated the growth and differentiation of monocytic cells from haemopoietic stem cells of the rat bone marrow. These results suggest that particular cells, which produce haemopoietic biglycan, play significant roles in generation and maintenance of the hyperplastic changes associated with myasthenia gravis.

Semi-quantitative immunohistochemical studies on Thy-1 antigen expressed by thymic myoid cells.

Thy-1 antigen expression in the rat thymic myoid cell line R615B2 (Thy-1(+] and R613Ad (Thy-1(-] was studied with a semi-quantitative immunohistochemical assay without disrupting the cell cultures. With this assay, the quantity of Thy-1 antigen on R615B2 cells was detected separately in the cytoplasm and on the cell surface by the use of appropriate fixatives such as chilled ethanol and methanol + 0.3% H2O2. Extracellular Thy-1 antigen was also found in the culture supernatant of R615B2 cells. More than half of extracellular Thy-1 antigen remained in the supernatant even after 100,000 X g centrifugation. No form of Thy-1 antigen was detected at significant levels in R613Ad cells.

Haemopoietic biglycan produced by brain cells stimulates growth of microglial cells.

We have recently found that soluble biglycan purified from rat thymic myoid cells had haemopoietic activity capable of inducing preferential growth and differentiation of monocytic lineage cells from various haemopoietic sources, including brain microglial cells. In the present study, to understand developmental mechanisms of microglial/monocytic cells in the brain, we have attempted to identify haemopoietic activity of the brain biglycan. The mRNA and the immunological epitope of biglycan were detected in the rat brain homogenates and several rat glial cell lines. Immunohistochemical study showed that several different types of brain cells produced biglycan. During development biglycan synthesis in the brain appeared to be increased. The brain haemopoietic biglycan was easily separated by DEAE-Sepharose chromatography from the macrophage colony stimulating factor (M-CSF) which was concomitantly produced from the brain cells. The brain haemopoietic biglycan, purified through immunoaffinity column, indeed stimulated growth of primarily cultured microglial cells. Taken together, these results suggest that the haemopoietic biglycan plays an important role in generating brain-specific circumstances for development of microglial/monocytic cells.

A practical enzyme immunoassay for anti-acetylcholine receptor antibodies in myasthenia gravis.

A practical enzyme immunoassay (EIA) has been developed for the measurement of anti-acetylcholine receptor (AChR) antibodies in sera from patients with myasthenia gravis (MG). This system is based on the double antibody technique, using denervated rat muscle AChR labeled with horseradish peroxidase-linked alpha-bungarotoxin (HRP-alpha BGT). This method has the following advantages compared to conventional radioimmunoassay (RIA): (1) HRP-alpha BGT is more stable than [125I]alpha BGT and can be used for at least one year without any loss of the binding activity to AChR and enzymatic activity, (2) the procedure avoids the use of radioactive isotopes, and (3) the equipment for our EIA is more economical than that for RIA.

Role of bradykinin in the vascular permeability response induced by carrageenin in rats.

1 Bradykinin in carrageenin-induced inflammatory pouch fluid was measured by an enzyme immunoassay method. 2 The bradykinin showed a single peak in the 30-60 min period after the challenge and then decreased quickly, and there was a correlation between the bradykinin level and exudation of fluorescein-labelled bovine serum albumin in the first 60 min period. 3 Captopril (an inhibitor of kininase II) elevated both the bradykinin level in the inflammatory pouch fluid and vascular permeability, while DL-2-mercaptomethyl-3- guanidinoethylthiopropanoic acid (an inhibitor of kininase I) had no effect. 4 Soybean trypsin inhibitor (SBTI) inhibited the vascular permeability response in parallel with the decrease in the bradykinin level. 5 A bradykinin-degrading activity appeared in the pouch fluid within 1 h after the challenge and increased with time. 6 In the period of 3.5-4 h, bradykinin levels were suppressed below the sensitivity limit of the assay, i.e. 0.07 nm ml-1, in spite of active generation. This was because degradation of bradykinin was very rapid in this late stage. Nevertheless, bradykinin still played a definite role in sustaining a high level of vascular permeability response in the late stage in conjunction with prostaglandins.

Isolation of a Ca-dependent erythrolytic protein (perforin) from cytotoxic T-lymphocytes.

A Ca-dependent erythrolytic protein (perforin) was isolated from a cytotoxic T-cell line (CTLL2). Cellular extracts were fractionated on DEAE-cellulose and hydrophobic Phenyl-Sepharose columns. Lytic activity was tightly bound to the hydrophobic column and was eluted with 50% ethyleneglycol. The erythrolytic activity was dependent on the concentration of Ca2+ ions, and heparin accelerated the lysis of erythrocytes by perforin 10-fold, with a half maximal concentration of 12 ng/ml. The activity was strongly inhibited by micromolar concentrations of heavy metal ions, such as Zn2+ and Fe2+, and glycylarginine-methylcoumarinamide (Gly-Arg-MCA) in the presence of 100 ng/ml heparin.

Astrocyte growth enhanced by culture supernatant of a cloned rat thymic myoid cell.

A conditioned medium (CM) from a cloned rat thymic myoid cell (IT-45R92) was used to investigate a possible relationship between the thymus and brain. CM stimulated the DNA synthesis of the cultured perinatal rat brain cells and spleen myelo-lymphoid cells but not that of the other types of cells including dorsal root ganglia, spinal cord, heart muscle, skeletal muscle, kidney, liver, skin, and thymic fibroblasts. CM appeared to stimulate glioblasts to differentiate into mature astrocytes that have a characteristic intracellular fibrous structure and a glial fibrillary acidic protein. These results indicated that thymic myoid cells release (a) 'cytokine(s)' for the astrocytes and myelo-lymphoid cells, similar to a 'lymphokine' (glia cell stimulating factor, GSF) produced by murine and human lymphocytes stimulated with mitogens.

Antibodies against saline-soluble components of skeletal muscle in myasthenia gravis.

Antibodies against phosphate-buffered-saline extracts (SE) of non-acetylcholine receptor (AChR) skeletal muscle antigens were found in patients with myasthenia gravis (MG). The antigenicity of SE was distributed in three fractions with molecular masses of over 200 kDa, 90-150 kDa and 7-14 kDa on gel filtration. These fractions shared common antigenicities. Further analysis of 90-150 kDa fractions on sodium dodecyl sulphate polyacrylamide gel electrophoresis showed five major bands, ranging from 105 kDa to 275 kDa. The antibodies against SE were detected in 52% (58/112) of the MG patients; incidence and titres were higher in the thymoma group (n = 21; 90% and 0.872 respectively) than in the non-thymoma group (n = 91; 43% and 0.200, P less than 0.001). In patients without a thymoma, these antibodies were frequently observed in late-onset disease and the severe generalized form (P less than 0.01). In 4 of 7 ocular MG patients without anti-AChR antibodies, low but appreciable levels of anti-SE antibodies were found. In 73% (11/15) of generalized MG patients treated with prednisolone and thymectomy, anti-SE antibody titres changed in association with those of anti-AChR antibodies and with the clinical course. Both antibody titres increased synchronously in patients who developed crises.

Nature of kininase activity in the exudate in kaolin-induced inflammation of the air pouch type in rats.

Experimental inflammation was induced by injection of a suspension of kaolin in carboxymethylcellulose solution into a subcutaneous air pouch preformed on the back of rats. Endogenous bradykinin generated in the inflammatory pouch declined quickly unless kininase inhibitors were administered into the pouch. Bradykinin injected into the pouch brought about no significant increase in plasma exudation in the pouch unless kininase inhibitors were administered simultaneously. Although kininase I and II activities were present in normal rat serum, kininase II rather than kininase I was mainly responsible for the degradation of bradykinin in rat serum. In the pouch challenged with the kaolin suspension and vehicle, kininase II originating from the pouch wall tissue played a predominant role in the degradation of bradykinin while the role of kininases derived from the blood and inflammatory cells was minor.

Possible site of action of TAK-637, a tachykinin NK(1) receptor antagonist, on the micturition reflex in guinea pigs.

TAK-637((aR,9R)-7-[3,5-bis(trifluoromethyl)benzyl]-8,9,10, 11-tetrahydro-9-methyl-5-(4-methylphenyl)-7H-[1,4]diazocino[2,1-g] [1,7]naphthyridine-6,13-dione) is a novel tachykinin NK(1) receptor antagonist that has been shown to inhibit the micturition reflex in guinea pigs. The aim of this study was to clarify its mechanism of action in guinea pigs. TAK-637 inhibited the spinal vesico-vesical reflex induced by electrical stimulation of the proximal cut end of the pelvic nerve in spinal animals, but not bladder contractions induced by electrical stimulation of the distal cut end of the nerve. Furthermore, TAK-637 had no effect on carbachol- or electrical field stimulation-induced contractions of isolated bladder muscle strips in an organ bath, whereas drugs used for abnormally frequent micturition inhibited both contractions. These results suggest that TAK-637 inhibits the micturition reflex by acting, at least in part, on the spinal cord, and its mechanism of action clearly differs from those of antimuscarinics or spasmolytics.

Effects of TAK-637, a tachykinin receptor antagonist, on the micturition reflex in guinea pigs.

The effects of a new tachykinin NK(1) receptor antagonist, (aR, 9R)-7-[3,5-bis(trifluoromethyl)benzyl]-8,9,10, 11-tetrahydro-9-methyl-5-(4-methylphenyl)-7H-[1,4]diazocino[2,1-g] [1, 7]naphthyridine-6,13-dione (TAK-637), on the micturition reflex were compared with those of drugs used for abnormally frequent micturition or incontinence. TAK-637 showed a characteristic effect on the distension-induced rhythmic bladder contractions in guinea pigs. The systemic administration of TAK-637 decreased the number but not the amplitude of the distension-induced rhythmic bladder contractions. A similar effect was observed in animals in which the spinal cord had been severed. TAK-637 also inhibited the micturition reflex induced by topical application of capsaicin onto the surface of bladder dome. From these results, it is concluded that TAK-637 inhibits sensory transmissions from the bladder evoked by both physiological and nociceptive stimuli by blocking tachykinin NK(1) receptors, possibly at the level of the spinal cord. On the other hand, the other drugs such as oxybutynin, tolterodine, propiverine, and inaperisone showed no effects on the frequency of the distension-induced rhythmic bladder contractions but decreased the contraction amplitude. Therefore, TAK-637 may represent a new class of drugs, which would be effective for abnormally frequent micturition without causing voiding difficulties due to decreased voiding pressure.