Immunosuppressive therapies for inflammatory bowel disease

Inflammatory bowel disease (IBD) is comprised of Crohn’s disease and ulcerative colitis, both chronic inflammatory intestinal disorders of unknown etiology characterized by a waxing and waning clinical course. For many years, the drug therapy was limited to sulfasalazine and related aminosalicylates, corticosteroids and antibiotics. Studies suggesting that the pathophysiology of these disorders relates to a disregulated, over-active immune response to indigenous bacteria have led to the increasing importance of immunosuppressive drugs for the therapy of IBD. This review details the mechanisms of action, clinical efficacy, and adverse effects of these agents.

At the crossroad of conception and infection: initiatives for immunoglobulin-based contraceptive R & D

Better understanding of the immunological mechanisms implying the insemination and the infertility of some menand women is needed and crucial to the development of an effective immunocontraceptive method. To provide goodprotection against conception or infection, and avoid any possible and unexpected comlications which immunocontra-ceptive 'vaccine' may arise of , it seems the right time for scientists to create a virtually new thinking for this extremelyurgent and important issue. This conceptual article describes our original thoughts of the future development of im-munocntraceptives, preferably, based on immunoglobulins rather than vaccines, against human sperm specific antigensand seminal plasma immunosuppressive factors. Its general correctness, advantages and feasibility for fertility regula-tion and prevention of infection are discussed. (Asian J Androl 1999 Sep; 1: 87-93)

Effect of Diallyl Trisulfide on the Activation of T Cell and Macrophage－mediated Cytotoxicity

At high concentration (50 μg/ml), diallyl trisulfide (DATS) had an inhibitory effect on T cell activation (compared with control group, P<0.05). But at appropriate concentrations(3.125-12. 5 μg/ml). DATS augmented the activation of T lymphocytes by Con A (compared with control group, P<0. 01). The augmentation of T cell activation by DATS was related to its inhibitory effect on the production of nitric oxide (NO) by macrophages.In a wide range of concentrations (1-100 μg/ml) , DATS can inhibit the production of NO by macrophas,es (P<0.05,P<0.01). In addition, DATS can antagonize the inhibition of tumor-derived immunosuppressive factors produced by S180 cells and Ehrlich ascitic cancer cells on the activation of T cells, and reduce the inhibitory rate significantly (P<0.01). DATS, despite its inhibition of the production of NO by macrophages, can significantly enhance the production of hydrogen peroxide (H2O2 by macrophages.When macrophages were pretreated with DATS for 24 h, the cytotoxicity % of macrophages to three tumor cell lines was significantly higher than that in corresponding control group (P<0.05,P<0.01). In the presence of both DATS and LPS, the cytotoxicity of macrophages was further enhanced so that the cytotoxicity % of macrophages to tumor cells was significantly higher than either that in the presence of DAIS alone or that in the presence of LPS alone(P<0.05, P<0.01). These results indicate that DATS can augment the activation of T cells and enhance the anti-tumor function of macrophage, suggesting that DATS may be potentially useful in tumor therapy.

STUDY ON THE MECHANISM OF ESCAPING IMMUNE SURVEILLANCE IN HUMAN GLIOMAS

Objective: To study mechanisms by which human gliomas may escape immune surveillance Methods: The effect of supernatant (SN) obtained from cultured media of malignant glioma cell lines on the proliferation of phytohemagglutinin p stimulated peripheral blood lymphocytes (PBLs) from healthy subjects and patients with gliomas was examined by MTT assay The immunosuppressive factor which might be existed in the SN was identified by neutralization method with specific antibodies and Northern blot hybridization of glioma cells In addition, the cellular immunity of patients with gliomas and relevant hormone and catecholamine were determined Results: It was found that the malignant glioma cells could release an immunosuppressive factor in an autocrine fashion which was further identified as the transforming growth factor β 2 (TGF β 2) It was also demonstrated that the plasma levels of norepinephrine in glioma patients were significantly reduced and correlated well with the suppression of the patients' own cellular immunity Conclusions: Two distinct mechanisms by which human gliomas may evade immune surveillance: 1 The secretion of an immunosuppressive factor which was identified as TGF β 2; 2 The dysfunction of Neuro Immune modulation in the presence of cerebral gliomas