草分支杆菌疫苗治疗哮喘模型小鼠的实验研究

目的　研究草分支杆菌疫苗对哮喘模型小鼠的疗效及其作用机制。方法　将 18只BALB/c小鼠分为3组 ,每组各 6只 ,其中卵蛋白致敏哮喘组 (OVA组 )和草分支杆菌疫苗治疗组 (Utilin组 )皮下注射卵蛋白致敏制作哮喘模型 ,然后用卵蛋白激发 2次 ;阴性对照组 (NS组 )皮下注射生理盐水 (NS) ,然后NS激发 2次。Utilin组在激发前后分别给予草分支杆菌疫苗 0 .5 μg腹腔注射 3次 ,其他两组不作干预。 3组分别在第 2次激发后第 1、2、3、4周眼眶后静脉丛采血测OVA特异性免疫球蛋白IgE ,并于激发后第 4周处死小鼠测肺泡灌洗液 (BALF)中的细胞总数及嗜酸性粒细胞 (EOS)计数 ,肺组织病理切片观察形态学改变 ,并测定脾细胞培养上清液中OVA特异性IFN γ。结果　Utilin组BALF中细胞总数为 (2 9.5 1± 5 .81)× 10 4 /mL、EOS为 (2 .88± 0 .96 )× 10 4 /mL ,明显低于OVA组 [分别为 (4 0 .15± 6 .12 )× 10 4 /mL和 (6 .91± 1.92 )× 10 4 /mL],P <0 .0 5 ;Utilin组肺组织炎症反应较OVA组明显减轻 ;Utilin组脾细胞培养上清液中OVA特异性IFN γ的浓度为 (4 6 9± 86 )pg/mL ,明显高于OVA组 (193± 80 ) pg/mL ,P <0 .0 5 ;Utilin组激发后第 3周和第 4周OVA特异性IgE分别为 (0 .2 99± 0 .0 92 )(OD值 ) ,(0 .2 6 7± 0 .0     

Construction of Shuttle Expression Plasmid and Stable Expression of Foreign Gene in Mycobacteria and E．Coli

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Induction and expression of protective T cells during Mycobacterium avium infections in mice.

Mycobacterium avium is an opportunistic pathogen that infects individuals suffering from chronic lung disease or immunocompromised patients such as AIDS patients. Here we show that a highly virulent isolate of M. avium proliferated as extensively in T cell deficient as in immunocompetent mice. T cell deficient mice allowed a progressive growth of a less virulent AIDS-derived isolate of M. avium while immunocompetent mice arrested the growth of this isolate. Adoptive transfer of T cell enriched spleen cells between congenic strains of mice differing at the Bcg/Ity/Lsh locus showed that only naturally resistant BALB/c.Bcgr (C.D2) mice infected with the highly virulent strain of M. avium or the naturally susceptible BALB/c mice infected with the lower virulence isolate developed protective T cells and that these cells only mediated protection when transferred to naturally susceptible, but not to naturally resistant, mice. Both strains of M. avium proliferated in bone marrow-derived macrophages cultured in vitro and they were both susceptible to the bacteriostatic effects induced in the macrophages by crude lymphokines produced by concanavalin A-stimulated spleen cells.     

The mode of action of treatment by IgG of haemolytic anaemia induced by an anti-erythrocyte monoclonal antibody

Tolerization of pathogenic antigens is one of the experimental strategies that has been proposed to prevent autoimmune disease. We have investigated here whether neonatal intraperitoneal infection of Lewis rats with Mycobacterium bovis-BCG has any effect on the expression of adjuvant arthritis (AA), an autoimmune disease that is produced by immunization of the rats with dead mycobacteria in mineral oil (i.e. Freund's complete adjuvant (FCA)). We found that neonatal infection with 10⁸ viable BCG bacilli rendered all Lewis rats resistant to the expression of AA after FCA immunization. This BCG-induced protection from reactive arthritis was not seen in Lewis rats infected with smaller inocula (10⁶ BCG bacilli) or if the infection was performed after the neonatal period (e.g. at 3 weeks of age). Neonatal administration of 65-kD mycobacterial heat shock protein (hsp65, a key antigen in the etiopathogenesis of AA) failed to protect Lewis rats from AA; injection of lactoferrin (an autoantigen that may be involved in the physiopathology of autoimmune arthritis) to newborn Lewis rats decreased the severity of AA observed after FCA immunization of the animals. Western blotting revealed that Lewis rats that had acquired resistance to AA also showed changes in their repertoire of antibody specificities; among these alterations was decreased anti-hsp65 reactivity. We conclude that neonatal infection with BCG, but not hsp65 injection, renders Lewis rats resistant to AA and that the phenomenon is associated with change in the repertoire of specificities of circulating antibodies.     

Disease association of antibodies to human and mycobacterial hsp70 and hsp60 stress proteins.

Structural homology between microbial and human stress proteins has been postulated to be a basis for autoimmunization in chronic inflammatory diseases. Therefore, we estimated by ELISA titration the antibody levels to mycobacterial (M) and human (H) recombinant hsp70 and M-hsp65 heat-shock proteins in sera of patients with Crohn's disease (n = 29), ulcerative colitis (n = 20) and nontuberculous mycobacterial disease of the lungs (n = 20). Antibodies to H-hsp60, separated by two-dimensional gel electrophoresis, were tested in six sera of each group of patients. In Crohn's disease, antibody titres to the M-hsp65 antigen without detectable H-hsp60 binding were significantly elevated in 52% of the patients. In contrast titres to both M-hsp70 and H-hsp70 were demonstrable and correlated, but increased over control values only in four (14%) patients. The antibody pattern in ulcerative colitis was found to be quite different: anti-H-hsp60 binding was demonstrable in most patients, although anti-M-hsp65 titres were not elevated. Furthermore, 25% of patients had significantly elevated titres to M-hsp70, but not to H-hsp70. In non-tuberculous mycobacterial pulmonary disease, about 50% of patients had elevated titres to both hsp65 and hsp71 mycobacterial antigens but not to the corresponding human proteins; patients with Mycobacterium xenopi infection had the highest titres in this group. These results demonstrate the existence of distinct disease-associated patterns in the human antibody response to stress protein antigens. However, these data are not sufficient to imply sensitization with mycobacteria in patients with inflammatory bowel diseases, since certain epitopes of heat-shock proteins are shared by several bacterial genera.     

Epitope focus, clonal composition and Th1 phenotype of the human CD4 response to the secretory mycobacterial antigen Ag85

Lymphoproliferation of healthy donors was tested against mycobacterial antigens (PPD, Ag85, Ag85 peptides). All PPD responders recognized the secretory antigen Ag85 and the peptide specificity for Ag85B was defined. Peptide 91-108 was recognized by 85% of donors. In addition, all CD4 T cell lines generated from 12 donors against PPD or Ag85 responded to 91-108. When this peptide was used to generate T cell lines, the cells responded also to tuberculins from atypical mycobacterial species. Thus the cross-reactive peptide behaved as quasi-universal. The analysis of TCR-BV gene usage by cell lines showed that most Ag85-specific T cells correspond to 91-108-specific clonotypes. Intracytoplasmic staining of cell lines after phorbol myristate acetate stimulation resulted in dominance of interferon-gamma (IFN-gamma)-IL-4 double-positive cells, whereas antigen stimulation resulted in production of IFN-gamma only. The data show that peptide 91-108 is the major focus of the CD4 response to mycobacterial antigens in peripheral blood mononuclear cells and in T cell lines from PPD responders.     

Cell-mediated immune responses to mycobacterial antigens in patients with pulmonary tuberculosis and HIV infection

Lymphocyte proliferation and cytokine responses induced by a panel of mycobacterial antigens were compared in Portuguese donors with pulmonary tuberculosis (TB) with or without HIV co-infection, HIV⁺ patients and healthy Mantoux-positive controls. Control donors showed stronger proliferative responses than any of the patient groups, with secreted antigens (Mycobacterium tuberculosis (Mtb) 30 kD and short-term culture filtrate proteins (ST-CFP)), purified protein derivative (PPD) and Mtb H37Rv Sonicate (MtbS) inducing the strongest proliferation. Patients with pulmonary TB showed lower proliferation to PPD or to the 30-kD antigen. Responses to all the antigens (PPD, ST-CFP, MtbS, 70 kD, 65 kD, 38 kD, 30 kD and 10 kD) were higher in TB/HIV patients with CD4 counts 200 CD4⁺ T cells/mm³ compared with HIV alone (CD4 200 T cells/mm³), but were lost in both TB/HIV and HIV patients when CD4 counts fell below 200 T cells/mm³. Measurements of interferon-gamma (IFN-γ) in culture supernatants revealed that PPD, 30 kD, MtbS and ST-CFP induced the strongest Th1 response. Analysis of mRNA for IFN-γ, IL-4 and IL-10 confirmed that IFN-γ production was maintained in patients with pulmonary TB without any concomitant increase in IL-4 or IL-10 mRNA expression, although expression of IL-10 mRNA was increased if HIV infection was present. These results reveal that IFN-γ production is retained in pulmonary TB patients to a broad range of mycobacterial antigens, and that no switch to IL-4 production is seen even with HIV infection. Secreted antigens, and in particular ST-CFP, were the best inducers of IFN-γ secretion, confirming their role in protective responses to Mtb.     

Fecal Excretion of Mycobacterium leprae,Burkina Faso

Mycobacterium leprae was detected by optical microscopy, fluorescent in situ hybridization, and molecular detection in feces collected for the diagnosis of Entamoeba coli enteritis in a leprosy patient in Burkina Faso. This observation raises questions about the role of fecal excretion of M. leprae in the natural history and diagnosis of leprosy.