T-cell tolerance following bacterial glutamic acid decarboxylase [GAD] feeding in streptozotocin-induced diabetes

Autoimmune type 1 diabetes mellitus is caused by T-cell mediated immune destruction of the insulin-producing a-cell in pancreatic islets of Langerhans. Specificity of the auto-antibodies and of the auto-reactive T-cells has been investigated, in which several auto-antigens were proposed. To determine whether glutamic acid decarboxylase [GAD] feeding would induce oral tolerance of either T-cell or B-cell compartment in streptozotocin [STZ] diabetic rats. Rats in the experimental group were fed 2 mg/kg of GAD [extracted from Escherichia coli] 14 days before intra-peritoneal injections of streptozotocin [30 mg/kg body weight for 5 consecutive days]. Two control groups were considered: diabetic control group, which underwent STZ injections without receiving GAD, and normal control group. Systemic response was compared between the three groups. T-cells response was assessed by a proliferation assay of spleen cells and those of the B-cells by enzyme-linked immunosorbent assay [ELISA] for anti-GAD specific antibodies in serum. Compared with the diabetic control group, a significant reduction was observed only in the proliferative response of spleen cells, but not in the level of anti-GAD antibody. GAD feeding induces systemic T-cell tolerance in STZ-induced diabetes

Immune response following oral immunization with BCG encapsulated in alginate microspheres

Different methods have been used for BCG vaccination. Alginate microspheres are useful in delivery of vaccines to the gastrointestinal tract by oral route. To compare the immune response following oral microencapsulated and subcutaneous [SC] route administration of BCG vaccine in BALB/c mice. Alginate microspheres were produced by an internal emulsification method within olive oil. Four groups of mice were studied, including two groups receiving oral gavages of microencapsulated and free BCG, one receiving SC injection of BCG, and a control group. T cell proliferation, specific anti-BCG total IgG, and IgG subclasses [IgG1 and IgG2a] were compared between groups 5 and 12 weeks after vaccination. The best result was achieved using oral microencapsulated form in comparison with oral BCG alone. Delivery of oral BCG with alginate microspheres is an effective way to induce immune response in BALB/c mice

T Cell vaccination as a tool in the treatment of collagen induced arthritis in albino rats

Background: The effectiveness of T cell vaccination has been demonstrated in a variety of animal models of both induced and spontaneous autoimmune diseases. The purpose of this study was to test the T cell vaccination protocol to treat and prevent collagen induced arthritis [CIA] in a rheumatoid arthritis model

Methods: CIA was induced by an intradermal injection of an artheritogen substance at the right paw of each female Albino rat under ether anesthesia. T cells were achieved from spleens of syngeneic rats that developed full clinical features of CIA. Rats suffering from CIA were divided in case groups [4 rats/group] based on the degrees of their disease and were injected intraperitoneally once with a suspension of T cells to investigate the effects of autoreactive T cells on CIA. To investigate the preventive effects of autoreactive T cells on CIA, 12 normal rats were injected intraperitoneally once either with a suspension of T cells or PBS, respectively. The results were evaluated by clinical observation, histopathological and radiographic findings

Results: Intraperitoneal inoculation of T cells to rats suffering from CIA, suppressed the development of CIA in case rats in stage 2 of the disease but not the other case rats. Rats who received T cells as prevention, showed the mild signs of disease. Injection of artheritogen substance to the case rats didn't result in development of CIA but the control rats, showed signs of CIA

Conclusion: The results of this pilot study demonstrate that CIA presentations and signs can be subsided or suppressed by autoreactive T cells. The vaccination is most effective before onset of the disease and in early phases of CIA. Modifying and improving the protocol using more cases is recommended