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We constructed a food-grade expression system harboring a F1S1 fusion protein of Bordetella pertussis to be produced in Lactococcus lactis NZ3900 as a new oral vaccine model against whooping cough, caused by B. pertussis. F1S1 was composed of N-terminally truncated S1 subunit of pertussis toxin and type I immunodominant domain of filamentous hemagglutinin which are both known as protective immunogens against pertussis. The recombinant L. lactis was administered via oral or intranasal routes to BALB/c mice and the related specific systemic and mucosal immune responses were then evaluated. The results indicated significantly higher levels of specific IgA in the lung extracts and IgG in sera of mucosally-immunized mice, compared to their controls. It was revealed that higher levels of IgG2a, compared to IgG1, were produced in all mucosally-immunized mice. Moreover, immunized mice developed Th1 responses with high levels of IFN-γ production by the spleen cells. These findings provide evidence for L. lactis to be used as a suitable vehicle for expression and delivery of F1S1 fusion protein to mucosa and induction of appropriate systemic and mucosal immune responses against pertussis., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Effective vaccination against pathogens, which enter the body through mucosal surfaces, requires the induction of both mucosal and systemic immune responses. Here, mucosal as well as systemic immune responses in the lung and spleen of BALB/c mice which were orally vaccinated with a single dose of alginate-encapsulated bacille Calmette-Guerin ( BCG) were evaluated. Twenty weeks after immunization, the vaccinated mice were challenged intranasally with BCG. Twelve weeks after immunization and 5 weeks after challenge, the immune responses were evaluated. Moreover, immune responses were compared with those of mice that were vaccinated with free BCG by subcutaneous (sc) and oral routes. Twelve weeks after the immunization, serum IgG level was higher in the sc-immunized mice, while serum IgA level was higher in the orally immunized mice with encapsulated BCG. Significant productions of both IgG and IgA were only detected in lungs of mice orally immunized with encapsulated BCG. Proliferative and delayed-type hypersensitivity responses and IFN- γ production were significantly higher in mice immunized orally with encapsulated BCG, compared to mice immunized orally with free BCG. After challenge, the levels of IFN- γ were comparable between sc-immunized mice with free BCG and orally immunized with encapsulated BCG; however, significantly less IL-4 was detected in mice which had received encapsulated BCG via oral route. Moreover, significant control of the bacilli growth in the lung of the immunized mice after intranasal challenge with BCG was documented in mice vaccinated with encapsulated BCG. These results suggest that oral immunization with alginate-encapsulated BCG is an effective mean of inducing mucosal and systemic specific immune responses. [ABSTRACT FROM AUTHOR]

Background: Hepatitis B vaccination has been included in routine immunization of all individuals according to WHO recommendations since 1991. Despite successful coverage, 3-5% of recipients fail to mount a desirable protection level of Ab. Vaccine failure results from: emergence of mutation, immune failure of individuals, decrease in vaccine potency, and etc. The quality of Hepatitis B vaccine should be evaluated by a reliable method. Methods: The amount of vaccine antigen was measured through the in vitro assay of Hepatitis B vaccines which consists of multiple dilutions of the reference material and samples. The preparations were evaluated by Elisa to determine the amount of HBsAg. The data were analyzed by parallel-line analysis software. The in vivo assay was performed by inoculating multiple doses of the reference and sample preparations in Balb/c mice. A control group was also inoculated with vaccine matrix. Four weeks later, the mice sera were evaluated to determine the presence of antibodies against Hepatitis B by Elisa method. The data were analyzed by Probit analysis software. Results: Both methods were set up in our laboratory by which different batches of Hepatitis B vaccine were evaluated. It was observed that In vivo and In vitro methods provide comparable results. Therefore we can use the in vitro method for routine testing of HB vaccine quality control. Conclusion: In vitro method can be used in place of In vivo method because of its time and cost-effectiveness. Moreover, since no animals are used in in vitro method, it complies well with the 3R concept (Reduction, Refinement, and Replacement of animal testing) and the current tendency to use alternative method. [ABSTRACT FROM AUTHOR]