FTIR differentiation based on genomic DNA for species identification of Shigella isolates from stool samples.

Shigellosis is one of the major public health concerns in developing and low-income countries caused by four species of Shigella. There is an apparent need to develop rapid, cost-effective, sensitive and specific methods for differentiation of Shigella species to be used in outbreaks and health surveillance systems. We developed a sensitive and specific Fourier-transform infrared spectroscopy (FTIR) based method followed by principal component analysis (PCA) and hierarchical clustering analysis (HCA) assays to differentiate four species of Shigella isolates from stool samples. The FTIR based method was evaluated by differentiation of 91 Shigella species from each other in clinical samples using both gold standards (culture-based and agglutination methods) and developed FTIR assay; eventually, the sensitivity and specificity of the developed method were calculated. In summary, four distinct FTIR spectra associated with four species of Shigella were obtained with wide variations in three definite regions, including 1800-1550 cm-1, 1550-1100 cm-1, and 1100-800 cm-1 distinguish these species from each other. In this study, we found the FTIR method followed by PCA analysis with specificity, sensitivity, differentiation error and correct differentiation rate values of 100, 100, 0 and 100%, respectively, for identification and differentiation of all species of the Shigella in stool samples.

Adjuvanticity effect of sodium alginate on subcutaneously injected BCG in BALB/c mice.

Bacillus Calmette-Guerin (BCG) is the only available vaccine against tuberculosis. The research for an improved vaccine is currently a very active field of investigation. In the present study, adjuvanticity effect of sterile sodium alginate on subcutaneous BCG vaccination in BALB/c mice was investigated. Mice were vaccinated subcutaneously with BCG plus alginate and the immune response and protective effect were compared to those of mice vaccinated with BCG alone by the same route. Proliferative and delayed-type hypersensitivity responses, IFN-gamma, specific anti-mycobacterium total IgG, IgG1 and IgG2a production were significantly higher in mice immunized subcutaneously with BCG plus alginate in comparison with results of mice immunized with BCG alone. Following systemic infection with BCG, mice vaccinated with BCG plus alginate had lower mean bacterial count compared to those vaccinated with BCG alone. The immune responses induced by subcutaneous administration of BCG plus alginate were significantly better than the responses induced by standard BCG vaccination.

Oral administration of BCG encapsulated in alginate microspheres induces strong Th1 response in BALB/c mice.

Bacille Calmette-Guerin (BCG) is one of the first vaccines administered to the newborns in developing countries. As an alternative to parenteral administration of vaccines, oral vaccines offer significant logistical advantages. Successful oral immunization, however, requires that vaccine antigens be protected from gastric secretions. In the present study, BALB/c mice were vaccinated orally with BCG encapsulated in alginate microspheres and the immune responses and protective effect were compared with those of mice vaccinated with free BCG by subcutaneous and oral routes. Proliferative and delayed-type hypersensitivity (DTH) responses and IFN-gamma production were significantly higher in mice immunized orally with encapsulated BCG in comparison with results of mice immunized orally with free BCG. Following systemic infection with BCG, mice vaccinated with encapsulated BCG had lower mean bacterial count compared to those vaccinated orally with free BCG. The immune responses induced by oral administration of encapsulated BCG were equal to or better than the responses induced by standard BCG vaccination.

T Cell Tolerance Following Bacterial Glutamic Acid Decarboxylase (GAD) Feeding in Streptozotocin-Induced Diabetes.

BACKGROUND: Autoimmune type 1 diabetes mellitus is caused by the T-cell mediated immune destruction of the insulin-producing beta-cell in pancreatic islets of Langerhans. The specificity of the auto-antibodies and of the auto-reactive T cells has been investigated, in which several auto-antigens were proposed. OBJECTIVE: The purpose of this study was to determine whether glutamic acid decarboxylase (GAD) feeding would induce oral tolerance of either the T cell or B cell compartment in streptozotocin (STZ) diabetic rats. METHODS: Experimental rats were fed 2 mg/kg of GAD (extracted from Escherichia coli) 14 days before being given intra-peritoneal injections of streptozotocin (STZ, 30 mg/kg body weight for 5 consecutive days). Of the two control groups, one was the diabetic control, which underwent STZ injections without being given the GAD; and the second was the normal control group. Systemic responses were compared between the three groups. T cell responses were assessed by a proliferation assay of spleen cells, and those of the B cell, by enzyme-linked immunosorbent assay ELISA for anti-GAD specific Abs in serum. RESULTS: 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. CONCLUSION: We concluded that GAD feeding induces systemic T cell tolerance in STZ-induced diabetes.

Immune Response Following Oral Immunization with BCG Encapsulated in Alginate Microspheres.

BACKGROUND: Different methods have been used for BCG vaccination. Alginate microspheres are useful in delivery of vaccines to the gastrointestinal tract by oral route. OBJECTIVE: To compare the immune response following oral microencapsulated and subcutaneous (SC) route administration of BCG vaccine in BALB/c mice. METHODS: 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. RESULTS: The best result was achieved using oral microencapsulated form in comparison with oral BCG alone. CONCLUSION: Delivery of oral BCG with alginate microspheres is an effective way to induce immune response in BALB/c mice.