[Differential diagnosis and surgical management in chondrosarcoma of the jugular foramen]

Objective: To explore the diagnosis, surgical management and outcome of jugular foramen chondrosarcoma (CSA). Methods: Fifteen patients with jugular foramen CSA hospitalized in the Department of Otorhinolaryngology Head and Neck Surgery of Chinese PLA General Hospital from December 2002 to February 2020 were retrospectively collected,of whom 2 were male and 13 were female, aging from 22 to 61 years old. The clinical symptoms and signs, imaging features, differential diagnosis, surgical approaches, function of facial nerve and cranial nerves IX to XII, and surgical outcomes were analyzed. Results: Patients with jugular foramen CSA mainly presented with facial paralysis, hearing loss, hoarseness, cough, tinnitus and local mass. Computed tomography (CT) and magnetic resonance (MR) could provide important information for diagnosis. CT showed irregular destruction on bone margin of the jugular foramen. MR demonstrated iso or hypointense on T1WI, hyperintense on T2WI and heterogeneous contrast-enhancement. Surgical approaches were chosen upon the sizes and scopes of the tumors. Inferior temporal fossa A approach was adopted in 12 cases, inferior temporal fossa B approach in 2 cases and mastoid combined parotid approach in 1 case. Five patients with facial nerve involved received great auricular nerve graft. The House Brackmann (H-B) grading scale was used to evaluate the facial nerve function. Preoperative facial nerve function ranked grade Ⅴ in 4 cases and grade Ⅵ in 1 case. Postoperative facial nerve function improved to grade Ⅲ in 2 cases and grade Ⅵ in 3 cases. Five patients presented with cranial nerves Ⅸ and Ⅹ palsies. Hoarseness and cough of 2 cases improved after operation, while the other 3 cases did not. All the patients were diagnosed CSA by histopathology and immunohistochemistry, with immunohistochemical staining showing vimentin and S-100 positive, but cytokeratin negative in tumor cells. All patients survived during 28 to 234 months' follow-up. Two patients suffered from tumor recurrence 7 years after surgery and received revision surgery. No complications such as cerebrospinal fluid leakage and intracranial infection occurred after operation. Conclusions: Jugular foramen CSA lacks characteristic symptoms or signs. Imaging is helpful to differential diagnosis. Surgery is the primary treatment of jugular foramen CSA. Patients with facial paralysis should receive surgery in time as to restore the facial nerve. Long-term follow-up is necessary after surgery in case of recurrence.

[Pancreatic pseudocyst after pegaspargase treatment in six children]

Objective: To investigate the clinical characteristics and treatment of pancreatic pseudocyst after pegaspargase treatment in children. Methods: The clinical data of 6 children with pancreatic pseudocyst after pegaspargase treatment in the Department of Pediatrics in Peking University Third Hospital from July 2018 to February 2021 were analyzed retrospectively. Results: There were 4 males and 2 females, and their age of onset was 9.5 (5.8, 13.0) years. The total number of pegaspargase applications was 2.5 (2.0, 3.5) times. The course from the last dose of pegaspargase to the onset of pancreatitis was 11.0 (9.0, 17.2) days, and 42.5 (35.0, 129.5) days from the onset of pancreatitis to the diagnosis of pancreatic pseudocyst. Abdominal pain was the most prominent manifestation of pancreatitis (6/6). All of the 6 children were asymptomatic when pancreatic pseudocyst was noted, and were treated conservatively at first, but one case later developed intermittent abdominal distension or nausea after eating. All the cases had pancreatic pseudocyst enlargement during the conservative treatment. Three children were treated with endoscopic ultrasound-guided transgastric drainage, and the cyst disappeared from 10 days to 4 months after the operation. The other 3 children received endoscopic retrograde cholangiopancreatography (ERCP)-guided transpapillary drainage, but one of them turned to surgery due to pancreatic duct stricture, and in the rest 2 children the cyst disappeared at 1 and 3 months after operation respectively. Regarding safety issues, 1 child who received ERCP-guided transpapillary drainage had acute postoperative pancreatitis, which were improved after treatment, and the other 5 had no complications. Conclusions: Pancreatic pseudocyst after pegaspargase chemotherapy can be asymptomatic in the early stage, and should be diagnosed with a history of pegaspargase treatment and timely imaging examination. Conservative treatment is the first choice for asymptomatic pseudocyst. When the pseudocyst enlarges, different endoscopic drainage treatments are required according to whether the pseudocyst is connected with the main pancreatic duct.

Dysiscalarones A-E, scalarane sesterterpenoids with nitric oxide production inhibitory activity from marine sponge Dysidea granulosa

Dysiscalarones A-E (1-5), five new scalarane-type bishomoscalarane sesterterpenoids, were isolated from marine sponge Dysidea granulosa collected from the South China Sea, together with two known ones, honulactone A (6) and phyllofolactone I (7). The new structures were determined by extensive spectroscopic analysis including HR-ESI-MS and 1D and 2D NMR data, and their absolute configurations were assigned by single crystal X-ray diffraction analyses. The inhibitory activity of all the seven isolates on the production of nitric oxide (NO) stimulated by lipopolysaccharide (LPS) in mouse RAW 264.7 macrophages was evaluated. Of these metabolites, dysiscalarones A-B (1-2), honulactone A (6), and phyllofolactone I (7) showed inhibitory activities with respective IC₅₀ values of 16.4, 18.5, 2.6, and 3.7 μM, which suggested that the γ-methylated α,β-unsaturated γ-lactone might be the functional group. In addition, all the seven metabolites showed no significant cytotoxicity against lung cancer PC9 cell line at the concentration of 20 μM.

[Effect of oral administration of branched-chain amino acids supplementation on the mortality of patients with hepatocellular carcinoma: a meta-analysis]

Objective: To investigate the effect of oral administration of branched-chain amino acids (BCAA) supplementation on the mortality of patients with hepatocellular carcinoma (HCC) after treatment. Methods: Computer searching of PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, and Chinese Biomedical Literature Database was conducted to search for clinical controlled trials and randomized controlled trials (RCTs) on the effect of oral administration of BCAA on the mortality of patients with HCC. The retrieval time limit was from the time of the establishment of each database to December 30, 2019. Two researchers independently screened the literature and extracted the data. Another researcher assessed the risk of bias in the included studies and then used RevMan 5.3 software for meta-analysis. Results: A total of 14 studies were included with 1 179 patients. The overall results showed that oral administration of BCAA had no significant effect on the mortality of HCC patients at 1 year after treatment (RR=0.85, 95%CI:0.68-1.06, P=0.16), while the mortalities of patients at 3 years (RR=0.73, 95%CI: 0.61-0.88, P=0.000 7) and 5 years (RR=0.57, 95%CI:0.34-0.96, P=0.03) after treatment were significantly lower than those of the control group. The subgroup analysis showed that for radiofrequency ablation (RFA) patients, there was no significant difference in 1-year mortality between the BCAA group and the control group (RR=0.96, 95%CI:0.14-6.5, P=0.97), while 3-year mortality was significantly reduced (RR=0.59, 95%CI:0.43-0.81, P=0.001); for hepatectomy patients, there was no significant differences in 1 -and 3-year mortality between the two groups (RR=0.90, 95%CI:0.44-1.88, P=0.79; RR=0.97, 95%CI:0.71-1.33, P=0.85, respectively). In addition, as for albumin levels, BCAA supplementation significantly increased albumin levels without considering the treatment of HCC (SD=0.45, 95%CI: 0.29-0.90; P=0.000 1), but had no significant effect on hepatectomy patients (SD=0, 95%CI: -0.41-0.41, P=0.99). Conclusion: BCAA supplementation might improve liver reserve function and long-term prognosis of HCC patients, which was related to the surgical method. Supplementing BCAA reduced the long-term mortality of RFA patients, but had no significant effect on hepatectomy patients.

[Relationship between gene polymorphism at rs2228055 locus in the exon region of interleukin-10 receptor A and susceptibility to food allergy in children]

Objective: To investigate the relationship between gene polymorphism of rs2228055 locus in the exon region of interleukin-10 receptor A (IL-10RA) and susceptibility to food allergy in children. Methods: This was a case-control study. The food allergy group had 150 children who were diagnosed with food allergy in the Pediatric Food Allergy Clinic of Peking University Third Hospital from August 1, 2017 to November 30, 2018. Another 150 healthy children attended Child Health and Development Center in the same hospital were selected as control group. The genotypes of rs2228055 locus in both groups were detected by PCR re-sequencing. And the genotypes and allele frequencies of rs2228055 locus were compared between these two groups, as well as between food allergy children with positive and negative allergen specific IgE, and between those with and without involvement of different organs. Using the computer virtual mutation to stimulate the changes of amino acid caused by change of rs2228055 locus allele, to analyze the effect of amino acid changes on the structure of IL-10RA. The chi-square test was used for comparison between groups. Results: (1) There were 92 males and 58 females in food allergy group, and 86 males and 64 females in control group, without any statistically significant difference (χ(2)=0.497, P=0.481). The ages of the two groups were 4.2 (0.1-15.0) and 8.0 (0.1-14.0) years old, respectively, the difference was statistically significant (Z=-6.109, P<0.01). (2) The genotype frequencies of rs2228055 locus in the food allergy group and the control group were as follows: AA accounted for 73 (48.7%) and 98 (65.3%), AG accounted for 62 (41.3%) and 42 (28.0%), and GG accounted for 15 (10.0%) and 10 (6.7%), respectively. The allele frequencies in the two groups were as follows: 208 (69.3%) and 238 (79.3%) for A, 92 (30.7%) and 62 (20.7%) for G, respectively. AG and GG genotype frequency and the allele G frequency in food allergy group were significantly higher than that in control group (χ(2)=8.501 and 7.862, P=0.014 and 0.005, respectively). (3) There were no significant differences in genotype frequencies and allele frequencies of rs2228055 locus of allergen-specific IgE-positive and negative food allergy children (all P>0.05). (4) There were no significant differences in genotype frequencies and allele frequencies of rs2228055 locus in the manifestations of skin, digestive system and respiratory system in food allergy children (all P>0.05). (5) The computer virtual mutation showed that the mutation energy was -0.08 without any increase in the stability of IL-10RA when the amino acid encoded by rs2228055 locus was changed from isoleucine to valine. Conclusions: The frequencies of genotype AG, GG and allele G of rs2228055 locus in the IL-10RA exon region in food allergy children are higher than that in non-allergic children, and those with the G allele are more likely to develop food allergy.

[Clinical study of psychological changes and post traumatic stress disorder in elderly patients with hip fracture]

Objective: To explore the psychological state and affected factors of elderly patients with hip fractures. Methods: A retrospective analysis of 156 elderly hip fracture patients(>65 years) admitted to the Department of Orthopaedics, the First Affiliated Hospital of Harbin Medical University from January 2016 to August 2019 was performed. General and psychological information were collected by questionnaire.General information included age, gender, education, whether surgery, length of stay.SCL-90, a self-assessment scale, was chosen as the psychological test to analyzed the elderly hip fracture patients' psychological status during hospitalization and the norms of SCL-90 in Chinese which were established in 1986 were used as the control group. The prognostic factors were examined by univariate and multivariate analysis. Results: Somatization, interpersonal sensitivity, depression, anxiety, paranoid factor scores, and total scores of the elderly hip fracture patients were significantly higher than control group(all P=0.00).Univariate analysis and logistic regression analysis showed that non-surgery treatment and more than 10 days of hospitalization were independent prognostic factors that affected the psychological state of elderly hip fracture patients (all P=0.00). Conclusion: Elderly patients hospitalized with osteoporosis and hip fractures are prone to have negative emotional and psychological changes.The length of hospitalization and the choice of treatment can affect patients' psychological state, suggesting that effective psychological intervention is necessary.

Spiroetherones A and B, sesquiterpene naphthoquinones, as angiogenesis inhibitors from the marine sponge Dysidea etheria

Spiroetherones A (1) and B (2), a pair of sesquiterpene naphthoquinones with an unprecedented “spiroetherane” carbon skeleton, were isolated from the marine sponge Dysidea etheria collected from the South China Sea.

[The influence of different thyroid stimulating hormone cut-offs to diagnose subclinical hypothyroidism during the first trimester of pregnancy]

Objective: To analyze the influence of different thyroid stimulating hormone (TSH) cut-offs to diagnose subclinical hypothyroidism (SCH) in the first trimester of gestation. Methods: A total of 896 pregnant women were enrolled in Peking University International Hospital between October 2016 and March 2018. Among them, 421 pregnant women with single fetus who were conformed to the criteria of National Academy of Clinical Biochemistry (NACB), without adverse pregnancy outcomes and obstetric complications, were selected to establish their self-sequential longitudinal reference ranges of thyroid function. Then, SCH was diagnosed in the first trimester, using different TSH cutoffs, such as the upper limit of the first trimester-specific reference range, 4.0 mU/L recommended by the 2017 Guidelines of American Thyroid Association (ATA), 5.17 mU/L (Roche reagent) recommended by 2012 Guidelines of Chinese Society of Endocrinology and Chinese Society of Perinatal Medicine, and 2.5 mU/L recommended by 2011 Guidelines of ATA, respectively. Results: The TSH reference range was 0.12-4.16 mU/L in the first trimester. Using TSH>4.16, 4.0, 5.17 and 2.5 mU/L to diagnose SCH in the first trimester, the prevalence rates were 4.35% (39/896), 5.92% (53/896), 1.56% (14/896) and 20.87% (187/896), respectively. There was no statistically significant difference between the prevalence rates of SCH using the TSH upper reference limit of 4.0 mU/L and 4.16 mU/L (P=0.134). When TSH was defined as>4.0 mU/L to diagnose SCH, the sensitivity, specificity and Youden index was 97.4%, 98.2%, and 0.956, respectively. Conclusions: The TSH upper reference limit of 4.0 mU/L recommended by 2017 Guidelines of ATA can be used as a cut-off to diagnose SCH in first trimester for the areas without trimester-specific reference ranges for TSH in China.

Sensitive electrochemical enzyme immunoassay microdevice based on architecture of dual ring electrodes with a sensing cavity chamber

A novel electrochemical detection architecture was investigated for enzyme immunoassay sensors. Microchips with dual-ring working and counter electrodes, and a sensing cavity chamber were made on glass slides. The glass surface of the microchip was coated by 3-aminopropyltriethoxysilane (APTES). Goat IgG, as a example, was covalently captured on APTES-modified glass surfaces through glutaraldehyde (GA) as a cross-linker. Enzyme substrate, p-aminophenyl phosphate (PAPP) was prepared by electrolysis. The enzyme conversion from home-synthetic PAPP to p-aminophenol (PAP) was examined by differential pulse voltammetry (DPV). A competitive inhibition enzyme-linked immunosorbant assay (ELISA) was designed to test the system. Experimental results demonstrate that a detection limit of 118 fg/ml of goat IgG and a dynamic range of 118 fg/ml to 1.18 ng/ml, up to five orders of magnitude could be achieved. Due to its novel architecture design and electronic detection scheme, the method can be used to fabricate portable electrochemical ELISA lab-on-chip systems. The technology could have great potential in clinical diagnostic applications.

Inhibitory effect of C-type natriuretic peptide on L-type calcium channel currents in gastric antral myocytes of guinea pigs

The role of C-type natriuretic peptide (CNP) in the gastrointestinal tract is still unclear. This study was designed to investigate the effect of CNP on barium current (I(Ba)) through the L-type calcium channel in gastric antral myocytes of guinea pigs. The whole-cell patch clamp technique was performed in gastric antral myocytes isolated by collagenase in guinea pigs. CNP significantly inhibited I(Ba) in a dose-dependent manner at the concentrations of 0.001, 0.01, and 0.1 micromol/l, CNP inhibited I(Ba) to 81.56 +/- 2.48 %, 73.64 +/- 3.65 %, and 57.77 +/- 4.93 % of control at 0 mV, respectively. The values of steady-state half-inactivation voltage (33.6 +/- 2.6 mV and 33.8 +/- 3.4 mV, in control and CNP groups, respectively) or the half-activation voltage (-12.6 +/- 2.2 mV and 12.4 +/- 1.8 mV) of I(Ba) were not significantly changed (p > 0.05, n = 6). 8-br-cGMP (1 mmol/l) mimicked the effect of CNP on I(Ba), and the peak current of I(Ba) was inhibited from -403.84 +/- 61.87 pA to 318.94 +/- 67.17 pA (p < 0.05, n = 5). In the presence of LY83583 (0.1 micromol/l), a nonspecific inhibitor of guanylate cyclase, CNP (0.1 micromol/l)-induced inhibition of I(Ba) was partially blocked (n = 13, p < 0.05 ). However, when the cell was pretreated with zaprinast (0.1 micromol/l), an inhibitor of cyclic guanosine monophosphate (cGMP) sensitive phosphoesterase, the inhibitory effect of CNP on I(Ba) was significantly potentiated (n = 11, p < 0.05). KT5823 (1 micromol/l), a cGMP-dependent protein kinase (PKG) inhibitor, almost completely blocked CNP-induced inhibition of I(Ba). The results suggested that CNP can inhibit L-type calcium channel currents, and the inhibitory effect is mediated by pGC-cGMP-PKG-dependent signal pathway in gastric antral myocytes of guinea pigs.

Nasal administration of Schistosoma mansoni egg antigen-cholera B subunit conjugate suppresses hepatic granuloma formation and reduces mortality in S. mansoni-infected mice

Granulomatous inflammation in schistosomiasis is a delayed-type hypersensitivity reaction mediated by CD4+ T cells specific for parasite egg antigens (Ags). In an attempt to control T-cell responses leading to excessive harmful inflammation and granuloma formation, especially in the liver, BALB/c mice were intranasally (i.n.) treated with soluble Schistosoma mansoni egg Ags (SEA) conjugated to cholera toxin B subunit (CTB), a mucosa-binding protein with demonstrated capacity to suppress inflammatory T-cell functions after mucosal administration. Treatment with CTB-SEA significantly conjugate a reduced liver granuloma formation in infected mice associated with decreased SEA specific Th1- and Th2-type immune responses by liver leukocytes. Importantly, treatment with CTB-SEA conjugate also significantly reduced the mortality in chronically infected mice. In S. mansoni-infected large-granuloma forming CBA mice, i.n. treatment with purified Sm-p40, the major egg antigen, conjugated to CTB likewise significantly inhibited hepatic egg granuloma formation. A reduction of SEA-driven lymphoproliferation and of interferon (IFN)-gamma, interleukin (IL)-4 and IL-5 production, together with an increase in transforming growth factor (TGF)-beta1 production, were observed in splenic cells from CTB-Sm-p40-treated SEA-sensitized mice, as well as in liver leukocytes from CTB-Sm-p40-treated schistosome-infected mice. These results indicate that mucosal administration of SEA or purified Sm-p40 antigen in conjunction with CTB is highly effective in curtailing immunopathologic manifestations of schistosomiasis in vivo in infected hosts.

Enhanced immunological tolerance against allograft rejection by oral administration of allogeneic antigen linked to cholera toxin B subunit

A single oral intragastric administration of cholera toxin B subunit (CTB) conjugated to allogeneic thymocytes (ATC, 4 x 10(7) cells) under conditions allowing the CTB to bind the complex to GM1 ganglioside receptors was shown to be efficacious in inducing peripheral T cell tolerance associated with significant suppression of both primary and secondary accelerated rejection of heart allografts when tested in mice. Allogeneic in vivo delayed-type hypersensitivity (DTH), in vitro cytotoxicity responses, and mixed lymphocyte reactions (MLR) by T cells from mesenteric lymph nodes (MLN), popliteal lymph nodes (PLN), and spleen were significantly reduced in mice treated with the CTB-ATC conjugate, as were also the numbers of cells in these organs producing IL-2, IFN-gamma, or IL-4. In contrast, a marked increase in the production of IL-4 in Peyer's patches (PP) and of TGF-beta(1) in PLN was observed. The suppressive potential of T cells from PP and/or MLN after oral treatment with CTB-ATC was further evident by intraperitoneal transfer of such cells from CTB-ATC-treated animals to primed recipients, which led to marked suppression of both allogen-specific DTH and MLR responses. A critical role for PP in inducing peripheral tolerance after oral CTB-ATC treatment was indicated by the absence of tolerance induction in animals whose PP had been destroyed before treatment with CTB-ATC. The results indicate that the protection against allograft rejection by oral treatment with CTB-ATC is mediated by T cells and associated with a strong induction of IL-4 production at mucosal sites and TGF-beta(1) at the effector sites.

Oral administration of cholera toxin B subunit conjugated to myelin basic protein protects against experimental autoimmune encephalomyelitis by inducing transforming growth factor-beta-secreting cells and suppressing chemokine expression

The efficacy and mechanism of immunosuppression against experimental autoimmune encephalomyelitis (EAE) by oral low-dose administration of myelin basic protein (MBP) conjugated to cholera toxin B subunit (CTB) were investigated in Lewis rats immunized with MBP together with complete Freund's adjuvant 4 days before the start of treatment. Oral treatment with CTB-MBP conjugate gave almost complete protection against disease, an effect that was totally abrogated by including a low dose of cholera holotoxin (CT). The protection by CTB-MBP was associated with a dramatic reduction in the number of leukocytes staining for CD4, CD8, IL-2R or MHC class II in the spinal cord as examined by immunohistochemistry. The mRNA expressions of T(h)1 cytokines IFN-gamma, IL-12 and tumor necrosis factor-alpha, as well as of chemokines monocyte chemotactic protein (MCP)-1 and RANTES in the spinal cord were also reduced by 76-94%, as assessed by in situ hybridization. In contrast, transforming growth factor (TGF)-beta mRNA-expressing cells were strongly increased in the spinal cord from animals treated orally with the CTB-MBP conjugate. In the draining peripheral lymph nodes, the number of MBP-specific TGF-beta mRNA-expressing cells was also increased, whereas there was a decrease in cells expressing T(h)1 or T(h)2 cytokine mRNA. Protection against EAE could be transferred by injection of cells from the mesenteric lymph nodes of animals fed with CTB-MBP into naive animals exposed to encephalitogenic T cells. The results indicate that the protective anti-inflammatory effect by oral treatment with CTB-MBP conjugate is, to a large extent, due to the induction of TGF-beta-secreting suppressive-regulatory T cells and to local down-regulation of MCP-1 and RANTES in the spinal cord.

[A study of low temperature catalyst for Sabatier reaction]

Objective. To develop a low temperature catalyst for the Sabatier CO2 reduction of the atmospheric regeneration system and lower the start-up temperature of the Sabatier reaction. Method. A low temperature catalyst was designed from the considerations of the active composition, the choice of the carrier, the production method and condition of the catalyst. Then the performance of the newly developed low temperature catalyst was tested. Result. A new low temperature catalyst for the Sabatier reaction using Ru as the active composition and using r-Al2O3 as the carrier was developed. The start-up temperature was lower than 110 degrees C and the start-up time was 8 min; The conversion efficiency of the lean component (H2 or CO2) was over 95 percent when the temperature of the reactor was from 200 degrees C to 300 degrees C; The reaction product water was nearly colorless, transparent and neutral. Conclusion. The test results showed that the goals of the design are achieved and it is worthwhile to make further studies on the low temperature catalyst.

Prolonged oral treatment with low doses of allergen conjugated to cholera toxin B subunit suppresses immunoglobulin E antibody responses in sensitized mice

BACKGROUND

Oral tolerance is a long recognized method for inducing systemic immunological tolerance. However, large doses of antigen and frequent administrations are often required. By linking the antigen to the nontoxic mucosa-binding B subunit of cholera toxin (CTB), the required amount can be dramatically reduced. We have previously shown that mucosal administration of small amounts of antigens coupled to CTB can suppress peripheral Th1 cell-reactivity and associated inflammatory immunopathology in both naive and systemically-immunized animals. Induction of oral tolerance by repeated feeding of relatively small doses of antigen has, in some cases been shown to involve the generation of regulatory Th2-like CD4+ T cells, and hence could promote rather than suppress type I immunoglobulin (Ig) E-mediated allergic responses.

OBJECTIVES

We examined whether oral prophylactic or therapeutic administration of a model allergen coupled to CTB would modulate allergen-specific IgE responses in high IgE responder Balb/c mice.

METHODS

Ovalbumin (OVA) was used as a model allergen. Mice were treated perorally with free or CTB-coupled OVA before or after systemic priming with alum-adsorbed OVA. Allergen-specific IgE levels in serum were measured with the passive cutaneous anaphylaxis test at various time-points.

RESULTS

Oral administration of a single low dose of CTB-linked OVA, prior to systemic sensitization and challenge with OVA, suppressed allergen-specific serum IgE antibody responses. Treatment with comparable doses of free OVA was much less effective. Most importantly, oral treatment with CTB-OVA conjugate could also suppress an already initiated IgE antibody response, but to achieve such a 'therapeutic effect', administration of multiple low doses of conjugate over a long time was required. Oral treatment with CTB-OVA conjugate could also effectively suppress antigen-specific Th1-mediated delayed-type hypersensitivity. Thus treatment with a CTB-conjugated model allergen can affect a broad range of T-cell-driven immune responses, even in antigen-experienced animals.

CONCLUSION

These results may impact on the development of therapeutic vaccines against type I allergies.

[Safety analysis for astronaut and the personal protective equipment]

Objective. To analyze and study astronaut and his personal equipment safety. Method. Three of the most widely used approaches, failure mode and effect analysis (FMEA), fault tree analysis (FTA) and system hazards analysis (SHA) were used. Result. It was demonstrated that astronaut and the personal equipment are subjected to various potential hazards, such as human errors, astronaut illness, fire or space suit emergency decompression, etc. Their causes, mechanisms, possible effects and criticality of some critical potential hazards were analyzed and identified in more details with considerations of the historic accidents of manned spaceflight. And the compensating provisions and preventive measures for each hazard were discussed. Conclusion. The analysis study may be helpful in enhancing the safety of the astronaut and its personal protective equipment.

Treatment of experimental autoimmune arthritis by nasal administration of a type II collagen-cholera toxoid conjugate vaccine

OBJECTIVE

To assess the efficacy of intranasal administration of microgram amounts of type II collagen (CII) coupled to cholera toxin B subunit (CTB) with respect to the development of collagen-induced arthritis, even when given after the onset of clinically evident arthropathy.

METHODS

DBA/1 mice were immunized with CII to induce arthritis and were subsequently treated with CTB-CII, CTB-conjugated ovalbumin, or CII alone. The incidence and severity of arthritis were assessed clinically and histologically.

RESULTS

Treatment with CTB-CII conjugate effectively suppressed leukocyte infiltration into the synovium and prevented bone erosion. Comparable doses of unconjugated CII administered by the same route were relatively ineffective. Protection with nasal CTB-CII vaccine was associated with decreased production of interleukin-4 (IL-4), IL-6, and interferon-gamma and with reduced CII-specific IgG1 and IgG2a antibody responses in regional lymph nodes.

CONCLUSION

Nasal treatment with CTB-CII appears to result in decreased peripheral Th1 and Th2 responses to collagen. These results suggest that intranasal vaccination with CTB-CII may offer an effective immunotherapeutic means for the control of chronic polyarthritis.

Mucosal immunity and tolerance: relevance to vaccine development

The mucosal immune system of mammals consists of an integrated network of lymphoid cells which work in concert with innate host factors to promote host defense. Major mucosal effector immune mechanisms include secretory antibodies, largely of immunoglobulin A (IgA) isotype, cytotoxic T cells, as well as cytokines, chemokines and their receptors. Immunologic unresponsiveness (tolerance) is a key feature of the mucosal immune system, and deliberate vaccination or natural immunization by a mucosal route can effectively induce immune suppression. The diverse compartments located in the aerodigestive and genitourinary tracts and exocrine glands communicate via preferential homing of lymphocytes and antigen-presenting cells. Mucosal administration of antigens may result in the concomitant expression of secretory immunoglobulin A (S-IgA) antibody responses in various mucosal tissues and secretions, and under certain conditions, in the suppression of immune responses. Thus, developing formulations based on efficient delivery of selected antigens/tolerogens, cytokines and adjuvants may impact on the design of future vaccines and of specific immunotherapeutic approaches against diseases associated with untoward immune responses, such as autoimmune disorders, allergic reactions, and tissue-damaging inflammatory reactions triggered by persistent microorganisms.

Intranasal administration of a Schistosoma mansoni glutathione S-transferase-cholera toxoid conjugate vaccine evokes antiparasitic and antipathological immunity in mice

Mucosal administration of Ags linked to cholera toxin B subunit (CTB) can induce both strong mucosal secretory IgA immune responses and peripheral T cell hyporeactivity. In this study, intranasal (i.n. ) administration of CTB-conjugated Schistosoma mansoni 28-kDa GST (CTB-Sm28GST) was found to protect infected animals from schistosomiasis, especially from immunopathological complications associated with chronic inflammation. Worm burden and liver egg counts were reduced in infected animals treated with the CTB-Sm28GST conjugate as compared with mice infected only, or with mice treated with a control (CTB-OVA) conjugate. However, a more striking and consistent effect was that granuloma formations in liver and lungs of mice treated with CTB-Sm28GST were markedly suppressed. Such treatment was associated with reduced systemic delayed-type hypersensitivity and lymphocyte proliferative responses to Sm28GST. Production of IFN-gamma, IL-3, and IL-5 by liver cells was also markedly reduced after i.n. treatment of CTB-Sm28GST, whereas IL-4 production was not impaired. Intranasal treatment of infected mice with CTB-Sm28GST increased IgG1-, IgG2a-, IgA-, and IgE-Ab-forming cell responses in liver in comparison with treatment with CTB-OVA, or free Sm28GST. Most importantly, mucosal treatment with CTB-Sm28GST significantly reduced animal mortality when administered to chronically infected mice. Our results suggest that it may be possible to design a therapeutic vaccine against schistosomiasis that both limits infection and suppresses parasite-induced pathology.

[The present status and development of thermal control system of spacesuits for extravehicular activity]

With the extension of extravehicular activity (EVA) duration, the need for more effective thermal control of EVA spacesuits is required. The specific schemes investigated in heat sink system for EVA are discussed, including radiator, ice storage, metal hydride heat pump, phase-change storage/radiator and sublimator. The importance and requirements of automatic thermal control for EVA are also discussed. Existed automatic thermal control for EVA are reviewed. Prospects of further developments of thermal control of spacesuits for EVA are proposed.

Treatment of experimental autoimmune encephalomyelitis by feeding myelin basic protein conjugated to cholera toxin B subunit

Oral administration of autoantigens can prevent and partially suppress autoimmune diseases in a number of experimental models, Depending on the dose of antigen fed, this approach appears to involve distinct yet reversible and short-lasting mechanisms (anergy/deletion and suppression) and usually requires repeated feeding of large (suppression) to massive (anergy/deletion) amounts of autoantigens to be effective. Most importantly, this approach is relatively less effective in animals already systemically sensitized to the fed antigen, such as in animals already harboring autoreactive T cells and, thus, presumably also in humans suffering from an autoimmune disorder. We have previously shown that feeding a single dose of minute amounts of antigens conjugated to cholera toxin B subunit (CTB) can effectively suppress delayed-type hypersensitivity reactions in systemically immune animals. We now report that feeding small amounts of myelin basic protein (MBP) conjugated to CTB either before or after disease induction protected rats from experimental autoimmune encephalomyelitis. Such treatment was as effective in suppressing interleukin 2 production and proliferative responses of lymph node cells to MBP as treatment involving repeated feeding with much larger (50- to 100-fold) doses of free MBP. Different from the latter treatment, which led to decreased production of interferon-gamma in lymph nodes, low-dose oral CTB-MBP treatment was associated with increased interferon-gamma production. Most importantly, low-dose oral CTB-MBP treatment greatly reduced the level of leukocyte infiltration into spinal cord tissue compared with treatment with repeated feeding of large doses of MBP. These results suggest that the protection from experimental autoimmune encephalomyelitis achieved by feeding CTB-conjugated myelin autoantigen involves immunomodulating mechanisms that are distinct from those implicated by conventional protocols of oral tolerance induction.

Lyme neuroborreliosis: evidence for persistent up-regulation of Borrelia burgdorferi-reactive cells secreting interferon-gamma

The T-cell response to the aetiologic pathogen Borrelia (B.) burgdorferi in patients with Lyme neuroborreliosis (LN) and in control patients with other neurological diseases was examined by enumerating B. burgdorferi-reactive T cells secreting interferon-gamma (IFN-gamma) with an ELIspot assay. LN patients had elevated numbers of B. burgdorferi-reactive IFN-gamma secreting cells in blood and approximately 20-fold enriched in the cerebrospinal fluid (CSF). A positive correlation existed in CSF between B. burgdorferi-reactive IFN-gamma secreting cells and B cells secreting anti-B. burgdorferi IgG antibodies. The up-regulation of antigen-specific IFN-gamma secreting cells persisted in peripheral blood up to at least 9 months and in the CSF for at least 4 months after termination of treatment with antibiotics, when the patients were mostly free from clinical signs and symptoms due to LN. How IFN-gamma interplays with other cytokines and influences the pathogenesis of LN remains to be studied.

Recommended diagnostic criteria for occupational chronic lead poisoning

The present study aims to recommend the normal upper limit, the acceptable upper limit, the subclinical lead absorption and intoxication diagnostic criteria in an effort to re-evaluate the current national diagnostic criteria for the occupational chronic lead poisoning. The study was conducted on 330 lead exposed workers and 100 non-exposed controls based on the determination of blood and urinary lead, porphyrin metabolism indices, as well as other indices under a nationwide quality control program. The data were subsequently treated by the curve fitting, multi-step transformation to Gauss distribution, and discriminant analysis with the aid of a SAS software package. The relationships between the air lead and blood lead level with certain biological parameters indicative of excessive lead exposure and poisoning were well established. The sensitivity, specificity, accuracy, false positive and false negative results of these critical values were also fully evaluated. This study would be useful for the amendment of the new edition of the national diagnostic criteria for the occupational chronic lead poisoning in China and would provide new approaches for similar investigations.

Cholera toxin B subunit: an efficient transmucosal carrier-delivery system for induction of peripheral immunological tolerance

Oral administration of antigens, including allergens and autoantigens, may be an efficient way to prevent diseases associated with untoward immune responses to self- and non-self-antigens. However, this approach has met with limitations because it usually requires repeated administrations of large doses of antigen and is less efficient in an already immune host, and the effect is of short duration. We report that a single oral administration of minute amounts of particulate or soluble antigen coupled to the B subunit of cholera toxin (CTB) can markedly suppress systemic immune responses in naive and in systemically immune animals. Both early (2-4 hr) and late (24-48 hr) delayed type-hypersensitivity reactivities were strongly suppressed after feeding a single dose of CTB-conjugated antigen. Serum antibody responses were also decreased, although moderately, after oral administration of CTB-conjugated antigen. This strategy of tolerance induction, based on oral administration of small amounts of antigens conjugated to a mucosa-binding molecule, may find broad applications for preventing or abrogating untoward immune responses.

Optic neuritis and multiple sclerosis: the T cell repertoires to myelin proteins and MBP peptides change with time

Autoreactive T cells recognizing myelin basic protein (MBP), proteolipid protein (PLP) and MBP peptides have been described in multiple sclerosis (MS) and optic neuritis (ON), but their role in disease pathogenesis, if any, is unknown. A consistency of the T cell repertoire over the course of MS and ON should facilitate the development of specific immunotherapies. We have examined the T cell responses to autoantigens in two consecutive blood specimens taken from patients with ON and MS, and in two consecutive CSF specimens obtained from ON patients. As read-out numbers of T cells responding to antigen stimulation by the secretion of interferon-gamma were estimated. Pronounced differences in occurrence and numbers of T cells recognizing MBP, MBP peptides with the amino acid sequences 63-88, 110-128 and 148-165, and PLP were noticed in individual ON and MS patients over the course of disease. The MBP peptide among those three included, that was predominantly recognized by T cells in the individual patient, also varied over the course. The quantitative and qualitative changes of the myelin antigen-specific T cell response in MS and in ON, the latter to a certain extent reflecting the situation in early MS, do not favor the future useful development of specific immunotherapies in these diseases.

Autoimmune T cell repertoire in optic neuritis and multiple sclerosis: T cells recognising multiple myelin proteins are accumulated in cerebrospinal fluid

Monosymptomatic unilateral optic neuritis is a common first manifestation of multiple sclerosis. Abnormal T cell responses to myelin components including myelin basic protein (MBP), proteolipid protein (PLP), and myelin-associated glycoprotein (MAG) have been implicated in the pathogenesis of multiple sclerosis. Antigen-reactive T helper type 1 (Th1)-like cells that responded by interferon gamma (IFN-gamma) secretion on antigen stimulation in vitro were counted. Untreated patients with optic neuritis and multiple sclerosis had similarly raised levels of T cells recognising MBP, PLP, and MAG in peripheral blood. Such T cells were strongly enriched in CSF. None of these myelin antigens functioned as immunodominant T cell antigen characteristic for optic neuritis or multiple sclerosis. The autoimmune T cell repertoire was not more restricted in optic neuritis (as an example of early multiple sclerosis). The autoreactive T cell repertoires differed in blood compared with CSF in individual patients with optic neuritis and multiple sclerosis. No relations were found between specificity or quantity of autoreactive T cells in blood or CSF, and clinical variables of optic neuritis or multiple sclerosis, or occurrence of oligoclonal IgG bands in CSF. The role of raised MBP, PLP, and MAG reactive Th1-like cells found in optic neuritis and multiple sclerosis remains unexplained.

Multiple sclerosis: occurrence of myelin basic protein peptide-reactive T cells in healthy family members

Genetic factors influence the susceptibility to multiple sclerosis (MS). This disease is accompanied by augmented T cell responses to CNS myelin components such as myelin basic protein. To evaluate the familial occurrence of such T cell autoreactivity, we have studied 12 MS families including 37 healthy first-degree relatives for occurrence of numbers of interferon-gamma (IFN-gamma) secreting cells among blood mononuclear after culture in presence of myelin basic protein (MBP), eight synthetic MBP peptides and the control antigen acetylcholine receptor (AChR). There were no differences between MS patients and healthy family members regarding frequencies of autoreactive T cells recognizing MBP, the eight different MBP peptides or AChR. None of the MBP peptides predominated as T cell antigen among the MS patients or their unaffected family members. In some families the highest number of MBP peptide reactive T cells were found among unaffected family members. No correlation was observed between numbers of MBP or MBP peptide reactive T cells in various subjects and their HLA-DR-DQ phenotypes. In conclusion, this study has revealed the presence of MBP and MBP peptide reactive T cells of similar frequencies in MS patients and their healthy family members.

Immunopharmacologic modulation of experimental allergic encephalomyelitis: low-dose cyclosporin-A treatment causes disease relapse and increased systemic T and B cell-mediated myelin-directed autoimmunity

Therapies with immunosuppressive drugs in autoimmune experimental diseases often down-regulate disease but sometimes may lead to paradoxical disease exacerbation. To elucidate possible mechanisms behind such phenomena the effects were studied of mitoxantrone (Mx) and cyclosporin A (CsA) given at high and low doses on clinical course, and on autoreactive T- and B-cell responses in actively induced experimental allergic encephalomyelitis (EAE) in Lewis rats. Treatment with Mx and high dose CsA abrogated EAE and decreased dramatically the measured immune responses compared to vehicle-treated control EAE rats. Low-dose CsA treatment caused a disease relapse 20-30 days post immunization (p.i.). This relapse was accompanied by increased numbers of cells spontaneously producing IFN-gamma in the CNS and regional lymph nodes. Furthermore, anti-myelin and anti-MBP secreting cells were increased as were numbers of primed T cells that produced IFN-gamma in response to myelin antigens. It was concluded that these aspects of the myelin autoreactive immune response correlated well with clinical disease and are useful in evaluating immunotherapeutic intervention. Low-dose CsA treatment may interfere with systemic down-regulatory mechanisms acting on both T- and B-cell myelin-directed autoimmunity.

Number of interleukin-4- and interferon-gamma-secreting human T cells reactive with tetanus toxoid and the mycobacterial antigen PPD or phytohemagglutinin: distinct response profiles depending on the type of antigen used for activation

The enzyme-linked immunospot (ELISPOT) assay has been proven to be an efficient and sensitive method for the enumeration of single cells secreting antibodies or cytokines. Here we have used this method to determine the number of interleukin-4 (IL-4)- and interferon-gamma (IFN-gamma)-producing cells in vitro secondary responses to tetanus toxoid (TT) and the mycobacterial antigen (purified protein derivative; PPD) or the mitogen phytohemagglutinin (PHA). PHA-induced IL-4 and IFN-gamma secretion was well correlated suggesting polyclonal activation of cells. This was not the case with the specific antigens, where PPD preferentially induced IFN-gamma- and very few IL-4-producing cells, while TT-induced both IL-4 and IFN-gamma. These differences are probably a reflection of the types of immunity the two antigens induce, mycobacteria preferentially inducing a cell-mediated T helper type 1 (Th 1) type of immunity, while immunity to tetanus is an antibody-dependent, Th 2 type of response. In individuals recently boosted with TT, a significant increase in both IL-4- and IFN-gamma-producing cells in response to TT was seen at day 7 after boost, followed by decline. This was in contrast to what was seen in response to PPD where an increase of IFN-gamma-producing cells after the TT boost at day 7 persisted for at least 14 days. These results suggest that after an in vivo boost both antigen-specific and nonspecific T cells are activated and that antigen-specific cells home to other organs and therefore may be difficult to demonstrate in the circulation. Our data show that the ELISPOT assay is a powerful tool for determining the frequency of cells secreting cytokines. The assay has several advantages over other assays since it is sensitive, measures the number of actually secreting cells, and avoids the problems of binding of cytokines to their cell-bound or soluble receptors.

[The experience in the treatment of acute necrotic pancreatis]

24 case patients with acute necrotic pancreatis underwent dynamic CT examination at our hospital from 1990, of those patients suspected of pancreatic infection were performed direct bacteriologic sampling by CT-guided percutaneous aspiration. According to CT and bacterial results, we decided to whether operate or not. Meanwhile, multi-organ monitored and support therapy underwent. ANP mortalities reduced from 20.5% to 12.5%. We suggest that the dynamic CT and CT-guided aspiration is a safe, and rapid technique for distinguishing pancreatic infection from severe sterile pancreatitis, and may prove helpful in reducing the high morbidity and mortality associated with pancreatic infection.

Cord blood contains high numbers of autoimmune T cells recognizing multiple myelin proteins and acetylcholine receptor

To analyze Ag-specific T cell autoimmunity in the newborn, umbilical cord blood cells of newborns were investigated by an immunospot assay for occurrence and numbers of cells secreting IFN-gamma after short-term culture in presence of myelin basic protein (MBP), proteolipid protein, myelin associated glycoprotein, nicotinic acetylcholine receptor and the synthetic MBP amino acid sequences 1-20, 63-88, and 110-128. These Ag were chosen because they represent putative targets for autoimmune attack in multiple sclerosis and myasthenia gravis. Surprisingly, numbers of T cells recognizing MBP, proteolipid protein, MBP peptides, and acetylcholine receptor were high in cord blood of newborns compared to peripheral blood of patients with neurologic diseases. No immunodominant T cell epitope could be discerned among the Ag included. The responses to purified protein derivate and PHA were lower among cord blood cells than peripheral blood cells of adults. Parallel enumeration of autoimmune T cells in cord blood and peripheral blood obtained from corresponding mothers at delivery, revealed that the high cell numbers in newborns were not a result of contamination from the mothers blood. The high numbers of T cells recognizing nervous system myelin proteins and acetylcholine receptor in cord blood could have importance for the mechanism and timing of tolerance induction, and also reflect excessive myelination and receptor maturation at birth.

Cord blood contains high numbers of autoimmune T cells recognizing multiple myelin proteins and acetylcholine receptor

To analyze Ag-specific T cell autoimmunity in the newborn, umbilical cord blood cells of newborns were investigated by an immunospot assay for occurrence and numbers of cells secreting IFN-gamma after short-term culture in presence of myelin basic protein (MBP), proteolipid protein, myelin associated glycoprotein, nicotinic acetylcholine receptor and the synthetic MBP amino acid sequences 1-20, 63-88, and 110-128. These Ag were chosen because they represent putative targets for autoimmune attack in multiple sclerosis and myasthenia gravis. Surprisingly, numbers of T cells recognizing MBP, proteolipid protein, MBP peptides, and acetylcholine receptor were high in cord blood of newborns compared to peripheral blood of patients with neurologic diseases. No immunodominant T cell epitope could be discerned among the Ag included. The responses to purified protein derivate and PHA were lower among cord blood cells than peripheral blood cells of adults. Parallel enumeration of autoimmune T cells in cord blood and peripheral blood obtained from corresponding mothers at delivery, revealed that the high cell numbers in newborns were not a result of contamination from the mothers blood. The high numbers of T cells recognizing nervous system myelin proteins and acetylcholine receptor in cord blood could have importance for the mechanism and timing of tolerance induction, and also reflect excessive myelination and receptor maturation at birth.

Autoreactive T and B cell responses to myelin antigens after diagnostic sural nerve biopsy

To study whether nervous tissue trauma provokes myelin antigen autoreactive T and B cell responses in humans we examined consecutive blood samples from 7 patients with polyneuropathy undergoing diagnostic sural nerve biopsy and 8 control patients undergoing other types of minor surgery. The antigen-specific T cells were assessed by enumerating cells secreting interferon-gamma (IFN-gamma) in response to the myelin components P0, P2, myelin basic protein (MBP) and myelin associated glycoprotein (MAG), and to 4 selected MBP peptides. B cell mediated immunity was assessed by counting numbers of cells secreting antibodies directed against the myelin proteins. On day 7 after biopsy, there were 3-10-fold increased numbers of T and B cells reactive with P0, P2, MBP and MAG in blood of polyneuropathy patients compared to controls, while levels of cells recognizing purified protein derivate or responding to phytohemagglutinin (PHA) did not differ significantly. Comparison of prebiopsy levels on day 0 with post-biopsy levels on day 7 in the polyneuropathy patients revealed a significant increase in T cells recognizing P0, P2 and MAG, and in B cells secreting IgG antibodies against P0 and P2. On day 14 after nerve biopsy these differences were no longer seen. We suggest that in patients with polyneuropathy, sural nerve biopsy with the ensuing wallerian degeneration and myelin breakdown causes transiently increased levels of circulating myelin autoreactive T and B cells. It remains to be determined if this has a physiological role in nerve trauma responses and/or affects the clinicopathological course of the peripheral neuropathy.

T cells recognizing multiple peptides of myelin basic protein are found in blood and enriched in cerebrospinal fluid in optic neuritis and multiple sclerosis

The cause of multiple sclerosis (MS) is unknown. Recently reported abnormal T-cell responses to several myelin proteins and myelin basic protein (MBP) peptides in peripheral blood constitute one line of evidence that autoimmune mechanisms could be involved in the pathogenesis of the disease. Monosymptomatic unilateral optic neuritis (ON) is a common first manifestation of MS and important to examine for a possible restriction of the T-cell repertoire early in the disease. T-cell activities to MBP and the MBP amino acid sequences 63-88, 110-128 and 148-165 were examined by short-term cultures of mononuclear cells from cerebrospinal fluid (CSF) and blood in the presence of these antigens, and subsequent detection and counting of antigen-specific T cells that responded by interferon-gamma (IFN-gamma) secretion. Most patients with MS and ON had MBP and MBP peptide-reactive T cells in CSF, amounting to mean values of between about 1 per 2000 and 1 per 7000 CSF cells and without immunodominance for any of the peptides. Numbers were 10-fold to 100-fold lower in the patients' blood. Values were similar in ON and MS, and no evidence was obtained for a more restricted T-cell repertoire in ON. The MBP peptide-recognizing T-cell repertoire was different in CSF than in blood in individual patients with ON and MS, thereby giving further evidence for an autonomy of the autoimmune T-cell response in the CSF compartment. No relations were observed between numbers of autoreactive T cells and presence of oligoclonal IgG bands in CSF or abnormalities on magnetic resonance imaging of the brain in ON or clinical variables of MS. The high numbers of MBP and MBP peptide-reactive T cells could play a role in the pathogenesis of ON via secretion of effector molecules, one of them being IFN-gamma, as well as in the transfer of ON to MS.

The T-cell repertoire in myasthenia gravis involves multiple cholinergic receptor epitopes

Antibodies against the alpha-subunit of the acetylcholine receptor (AChR) are found in most patients with myasthenia gravis and are considered to contribute to the receptor damage which leads to the characteristic signs and symptoms of the disease. This B-cell response is T-cell driven. Elevated T-cell reactivities to AChR and its alpha-subunit have been described in myasthenia gravis, and AChR alpha-subunit peptide reactive T-cell lines and clones preferentially recognizing certain defined sequence segments have been reported, thereby disclosing the possibility of specific immunotherapy. We have defined the T-cell repertoire to AChR, its alpha-subunit and the synthetic peptide sequences 100-117, 113-130, 143-163, 161-179, 207-225, 221-240, and 235-255 of the alpha-subunit in an immunospot assay which is based on secretion of interferon-gamma (IFN-gamma) by individual memory T cells upon stimulation with specific antigen in short-term cultures. Most patients with myasthenia gravis displayed T-cell reactivities to 1 to 6 different peptides. The mean numbers of T cells recognizing individual peptides varied in the myasthenia gravis patients between 1 per 77,000 and 1 per 167,000 peripheral blood mononuclear cells. None of the seven peptides evaluated could be identified as an immunodominant T-cell epitope, and any of them was found to dominate in individual patients. The numbers of T cells reacting with AChR and recombinant human AChR alpha-subunit were slightly higher (mean numbers 1 per 26,000 and 1 per 50,000 mononuclear cells, respectively). Such cells, as well as AChR alpha-subunit peptide reactive T cells, were also found in patients with other neurological diseases and in healthy subjects, but at lower frequencies and numbers. In myasthenia gravis, the elevated numbers of memory T cells recognizing multiple AChR alpha-subunit peptides may be crucial for the development of the disease, and the IFN-gamma released by such T cells might be important for its perpetuation.

T cell responses to human recombinant acetylcholine receptor-alpha subunit in myasthenia gravis and controls

Antibodies against the nicotinic acetylcholine receptor (AChR) of the neuromuscular junction are detectable in most patients with myasthenia gravis (MG) and assumed to participate in the destruction of the AChR, thereby, causing the characteristics signs and symptoms of the disease. The extent and importance of T cell responses to AChR and its subunits in MG are still unsettled. We have now examined T cell reactivities using human recombinant AChR-alpha subunit as antigen. Upon recognition of appropriate antigen in an MHC-class II-restricted fashion, memory T cells secrete interferon-gamma (IFN-gamma). Adopting this principle in an immunospot assay we found that 73% of MG patients had recombinant human AChR-alpha subunit-reactive T cells at a median value of 1 per 56,000 blood mononuclear cells, while only 27% of the MG patients responded to the alpha subunit in a conventional lymphocyte proliferation assay. This compares with even lower numbers of AChR-reactive T cells and 14% positivity in the proliferation assay among control subjects. The T cell responses to the control antigens purified protein derivative and myelin basic protein did not differ between MG and controls, underlining the specificity of an augmented T cell reactivity to AChR-alpha subunit in MG. Alpha Subunit-specific T cell lines and clones propagated from patients with MG and healthy controls yielded a high proportion of alpha subunit-reactive T cells in the IFN-gamma immunospot assay. Their appearance was inhibited by the addition of monoclonal anti-MHC class II antibodies, demonstrating that an MHC-restricted T cell response was measured. Our data underline that the AChR-alpha subunit is a major T cell autoantigen in MG.

Myasthenia gravis: T and B cell reactivities to the beta-bungarotoxin binding protein presynaptic membrane receptor

Antibodies against acetylcholine receptor (AChR) can be detected in most patients with myasthenia gravis (MG) and are considered to be involved in the immunopathogenesis of this disease. AChR are isolated from crude receptor preparations by binding to alpha-bungarotoxin (alpha-BuTx). Patients with MG have also antibodies against a second protein tentatively named presynaptic membrane receptor (PsmR), which has been isolated from crude receptor utilizing beta-bungarotoxin (beta-BuTx). PsmR could represent another antigen besides AChR relevant for the development of MG. We have now evaluated the T cell reactivity to PsmR in MG and controls by analysing the frequencies of cells which in response to PsmR in short-term cultures secreted interferon-gamma (IFN-gamma). The B cell response to PsmR was analysed in parallel by counting cells secreting anti-PsmR antibodies. Most patients with MG had PsmR reactive T cell in blood with a median number of about 1 per 44,000 mononuclear cells. Cells secreting anti-PsmR antibodies belonging to the IgG and IgA isotypes, less frequently of the IgM isotype were detected in most MG patients. A positive correlation was found between T cells reactive with PsmR and anti-PsmR IgG antibody secreting cells. PsmR reactive T and B cells were also detected in control patients, but at much lower numbers. Our results indicate that MG is accompanied by T as well as B cell responses to PsmR, in addition to the previously recognized responses to AChR. It remains to be shown whether these PsmR reactivities are of pathogenetic importance in MG.

Virus-reactive and autoreactive T cells are accumulated in cerebrospinal fluid in multiple sclerosis

Elevated numbers of B cells--plasma cells secreting antibodies to measles and mumps virus, and to myelin associated glycoprotein (MAG), one of several putative myelin autoantigens--have previously been reported in cerebrospinal fluid (CSF) from patients with multiple sclerosis (MS), while it is unknown if corresponding T cell reactivities occur. We have defined the T cell reactivities to measles and mumps virus and to MAG in an immunospot assay which is based on the detection of secretion of interferon-gamma (IFN-gamma) by single cells upon stimulation with specific antigen in short term cultures. Patients with MS had higher numbers of MAG-reactive T cells in blood compared to controls, while no differences were observed for measles or mumps virus-reactive T cells. In CSF, elevated numbers of MAG-reactive T cells and also of measles- and mumps-reactive T cells were found in patients with MS compared to other neurological diseases. A strong accumulation of antigen-reactive T cells was observed in the MS patients' CSF compared to blood. The magnitude of these T cell reactivities did not correlate with clinical MS variables. The T cell repertoire in MS thus includes, besides myelin basic protein, proteolipid protein and myelin oligodendrocyte glycoprotein, also MAG and, in addition, measles and mumps virus. It is not clear whether these T cell reactivities accumulated in the CSF have importance for the pathogenesis of MS or reflect phenomena secondary to myelin damage, or result from both these alternatives.

Conjugal multiple sclerosis: immunogenetic characterization and analysis of T- and B-cell reactivity to myelin proteins

We describe two families with conjugal multiple sclerosis. Onset of symptoms in the husbands occurred 11 and 17 years after onset of relapsing/remitting symptoms in their wives. There were no similarities regarding clinical manifestations of MS within each family. Evaluation of T-cell repertoire by enumeration of cells secreting interferon-gamma in response to proteolipid protein (PLP), myelin basic protein (MBP), and to various synthetic MBP peptides revealed similar patterns of T-cell reactivity within the families both in MS-affected parents and unaffected children. Genomic HLA-DR-DQ typing showed that T-cell reactivity was independent of HLA class II phenotype. Analysis of B-cell responses in blood showed low numbers of cells secreting IgG, IgA, or IgM antibodies against MBP, PLP, myelin-associated glycoprotein, and myelin-oligodendrocyte glycoprotein both in MS-affected and unaffected family members. In conclusion, our study of two families with conjugal MS has shown a dominant T-cell response against the same MBP peptide within the family both in MS-affected parents and unaffected children, and this T-cell response seems to be independent of the HLA class II phenotypes of the family members.

Autoreactive T and B cells responding to myelin proteolipid protein in multiple sclerosis and controls

The pathogenesis of multiple sclerosis (MS) could involve an autoimmune response to proteolipid protein (PLP). Immunization of experimental animals with this major myelin protein can lead to experimental allergic encephalomyelitis. To identify a possible role of PLP as target antigen in MS, we evaluated T cell immunity to PLP in blood and cerebrospinal fluid (CSF) from patients with MS and controls by counting cells which in response to PLP in short-term cultures secreted interferon-gamma. The PLP-specific B cell response was analyzed by counting cells secreting anti-PLP antibodies. PLP-reactive T cells were detected in blood of most MS patients (mean value 1 per 20,408 mononuclear cells), and at 41-fold higher numbers in CSF (mean 1 per 500 CSF cells). Anti-PLP IgG antibody-secreting cells were detected in blood from most MS patients (mean 1 per 30,303 cells), but such cells were 49-fold more frequent in CSF (mean 1 per 625 cells). PLP-reactive T and B cells were also detected in blood and CSF from control patients, but at much lower numbers. A strong and persistent autoimmune response to PLP as well as to other myelin proteins, enriched in CSF, is proposed to be pathogenetically important in MS.