فهرست مطالب khosrow issazadeh

Bacterial spores are among the most efficient vaccine delivery vehicles. Because of their safety and efficacy, Bacillus subtilis spores are increasingly used in this regard. The negatively charged surfaces of the spores allow antigens to be adsorbed onto these structures. In this study, a candidate vaccine against Salmonella enterica serovar Typhi was adsorbed onto B. subtilis spores and the immunogenicity of the formulation was investigated in BALB/c mice.

This work was performed during 2018-2019 in Islamic Azad University of Lahijan. FliC protein was recombinantly expressed in E. coli BL21 (DE3) cells and purified by affinity chromatography. On the other hand, B. subtilis strain PY79 (ATCC1609) was cultured in DSM medium and after the sporulation, FliC protein was adsorbed onto the spores in three different pH values (4, 7 and 10) and the adsorption was verified using dot-blot assay. FliC-adsorbed spores were then administered to BALB/c mice through the subcutaneous route. Mice immunization was evaluated by serum IgG assessment and challenge study.

FliC protein was successfully expressed and purified. Sporulation was controlled by phase-contrast microscopy. Serum IgG assay showed significant stimulation of the mice's humoral immune system. Immunized mice were able to resist bacterial infection.

The results showed the efficiency of spores as natural adjuvants for the stimulation of mice immune system. The formulation can be exploited for the delivery of recombinant vaccines against bacterial pathogens.

 Globally, Salmonella enterica serotype Typhi is responsible for more than 10 million enteric fever cases, annually. Because of the emergence of multidrug-resistant strains of many bacteria, including Salmonella Typhi, vaccination may be a preferred strategy to combat infectious diseases. In the present study, the efficiency of flagellin protein as a recombinant vaccine candidate was evaluated in BALB/c mice.

For this aim, flagellin protein was expressed in E. coli BL21 (DE3). Mice were grouped into two groups: test and control. The test group was immunized by the intraperitoneal administration of recombinant protein in combination with Freund's adjuvant. Following the completion of the immunization period, the mice were challenged by IP injection of 10 LD50 of live Salmonella Typhi and subsequent culture of their spleens and livers.

Flagellin protein expression was confirmed by SDS-PAGE and Western blotting. ELISA showed the proper stimulation of the humoral immunity of the immunized mice. The bacterial count decreased significantly in the spleens and livers of the immunized animals in comparison to the control ones.

Findings of this study show the efficiency of flagellin recombinant protein in protecting mice against Salmonella Typhi.

The Streptomycetes are gram positive bacteria with a filamentous form that present in a wide variety of soil including composts, water and plants. The most characteristic of Streptomycetes is the ability to produce secondary metabolites such as antibiotics. They produce over two-thirds of the clinically useful antibiotics of natural origin (e.g., neomycin and chloramphenicol. Another characteristic of Streptomycetes is making of an extensive branching substrate and aerial mycelium.Carbon and nitrogen sources, oxygen, pH, temperature, ions and some precursors can affect production of antibiotics. This review also addresses the different methods to study the antimicrobial activity of Streptomyces sp. Because of increasing microbial resistance to general antibiotics and inability to control infectious disease has given an impetus for continuous search of novel antibioticsall the word.