VACCINE RESEARCH
Year:2017 | Volume:4 | Issue:1-2|Papers Count:7

Tuberculosis (TB) is one of the most important public health problems in the world and has been declared as a global emergency by the World Health Organization (WHO) in 1993. Bacillus Calmette-Gué rin (BCG) is one of the first developed vaccines to prevent TB. Unfortunately, BCG vaccine has had a limited duration of protection and has shown controversial and variable levels of efficacy, especially against pulmonary TB. On the other hand, efforts in production of new forms of this vaccine have been in vain and revaccination is not considered as a suitable strategy to control the disease. Considering that TB affects adults mostly between the ages of 15 and 59, pulmonary TB is more common than disseminated TB and BCG vaccine has had a minimal effect on the global burden of pulmonary TB. Before introducing a new, safe and effective vaccine, combined strategies in the field of control and treatment of TB rather than vaccination are necessary.

Introduction: Influenza viruses are the major respiratory pathogens worldwide and high-risk groups such as healthcare workers may develop severe forms of the disease. The purpose of this study was to evaluate the cost-effectiveness of influenza vaccination for 4 target groups including pregnant women, elderly people (aged over 65 years), healthcare workers and school-age children in Iran. Methods: A cost-effectiveness analysis using a decision tree model over a one-year time horizon for the influenza vaccination versus no vaccination in Iran was carried out according to the prospective of the Ministry of Health. Epidemiological data were extracted from the relevant local databases and the literature. The medical and community care costs with sampling of the patients in all 4 groups were estimated. Results: The results of the economic evaluation showed that in Iran, incremental costs per Disability-Adjusted-Life-Years (DALY) of influenza were estimated to be US$ 15, 069, US$ 104, 104, US$ 5, 685 and US$ 14, 983 for the pregnant women, the elderly people, the healthcare workers and the school-age children, respectively. Conclusion: The results of this study indicated that the implementation of influenza vaccination program might be cost effective only for the healthcare workers.

Introduction: Hepatitis C virus (HCV) is one of the most serious causes of cirrhosis, liver cancer and ultimately death, worldwide. The new direct-acting drugs are not accessible for many patients around the world and progress toward new therapeutic and anaphylactic vaccines design has not been fast enough. This study was aimed to prepare and assess a recombinant fusion protein core-NS3 (rC-N) of HCV with the accompaniment of d, l-polylactide-co-glycolide nanoparticles (PLGA NPs) as a nano-conjugated vaccine candidate. Methods: The rC-N protein containing the first domain of core and middle region of NS3 (residues 1095-1384) was loaded into PLGA NPs (rC-N/PLGA NPs) by NHS and DDC (equimolar: 0. 5 mM) as conjugating agents. The morphology and average of surface roughness (Ra) of PLGA NPs and rC-N/PLGA NPs were demonstrated by atomic force microscope (AFM). The particle sizes, polydispersity index (PDI) and zeta potential were measured by Zetasizer. Results: The morphology of the nanoparticles was spherical and their surface Ra was measured to be 7. 630 nm for PLGA NPs and 15. 72 nm for rC-N/PLGA NPs. The average size (160. 4 nm), zeta potential (-37. 6 mV) and PDI (0. 227) were also obtained for rC-N/ PLGA NPs. Conclusion: The surface Ra value of rC-N/PLGA NPs (15. 72 nm) which was twice more than PLGA NPs (7. 630 nm) confirmed a successful conjugation. The stability of nanoparticles behavior in the colloid was confirmed by the absolute value of zeta potential (|-37. 6|= 37. 6 mV) of rC-N/PLGA NPs. The spherical morphology, average size < 200, an absolute value of zeta potential > 30 mV, PDI < 0. 5 were confirmatory indications that rC-N/PLGA NPs could be considered as vaccine candidate. The rC-N/PLGA NPs construct should be further evaluated via in-vivo challenges and demonstration of targeted delivery to the antigen presenting cells.

Introduction: Extracellular vesicles (EVs) are bacterial products with diverse biological roles. Like many microorganisms, Mycobacterium kansasii as a nontuberculous mycobacteria (NTM), can naturally release EVs. The aim of the present study was the extraction and biological evaluation of M. kansasii as a vaccine candidate against mycobacterial pulmonary infections. Methods: After bacterial culture of the standard species of M. kansasii, the EVs extraction was done by density gradient ultra-centrifugation method and biological evaluations of EVs were performed by SDS-PAGE and electron microscopy. Endotoxin safety of the EVs was evaluated by LAL test. Results: SDS-PAGE result showed more than 5 prominent protein bands (60-180 kDa). The intactness of the vesicles was verified by electron microscopy through which the spherical configuration of EVs with diameter of 200-300 nm could be observed. The amount of lipopolysaccharide (LPS) contamination existing in EVs was in the specified application range of biological products. Conclusion: EVs were prepared with acceptable quality composition with intact conformational structure throughout the extraction procedure. The extracted EVs had the initial requirements as an immunogenic molecule, such as safety, stability, inexpensiveness and antigens possession which based on the similarities between M. kansasii and M. tuberculosis, make them a suitable candidate for future prophylactics, therapeutic, detection and adjuvants studies against mycobacterial pulmonary infections.

Introduction: Human papillomavirus (HPV) 16 E7 protein is expressed constitutively by HPV-infected tumor cells. Mutant versions of E7 are considered as safer candidates for immunotherapy of cervical cancer. Different strategies including formulation with adjuvants are used to induce a potent immune response against antigenic proteins. Methods: In this experimental study, we used Escherichia coli as a host to recombinantly express wild-type E7 and its mutant non-oncogenic form as E7GGG. We formulated both antigens with Montanide ISA 266 adjuvant and evaluated IFN-γ and IL-4 cytokines and antibody levels and also tumor regression in tumor-harboring C57BL/6 mice. Results: It was demonstrated that formulation of E7 and E7GGG antigens with Montanide ISA 266 resulted in a Th2-biased immune response. In the therapeutic mouse model, these formulations resulted in significant tumor regression compared to the control group. Conclusion: The formulation of the wild-type E7 and mutant E7GGG with Montanide ISA 266 might not be an optimal approach to regress TC-1 induced tumor; however, such combinations might be considered as an additive approach for stimulating the immune responses.

Introduction: Influenza virus has several conserved peptides which have the capacity to be used as suitable candidates for appropriate and stable vaccine production against different types of influenza viruses. One of these peptides is HA2, the hemagglutinin stalk domain which mediates the membrane fusion and is conserved amongst different sub-types of influenza virus. This peptide is a good candidate for participation in vaccine structure to induce immunity and antibody production. The ensued antibody may hamper the membrane fusion and subsequently the virus propagation. Methods: The peptide sequence of HA2 from influenza virus A/Tehran/18/2010 (H1N1) was analyzed using in silico tools in order to evaluate its physicochemical properties and identification of its best immunogenic sites. The confirmed sequence was amplified and cloned into a pET28a vector and the recombinant protein was over-expressed prokaryotically and confirmed by Western blotting. Results: The bioinformatics data showed that HA2 peptide stability and immunogenicity. The generated HA2 construct was confirmed by PCR, endonuclease restriction enzyme analysis and sequencing. The expression of HA2 was confirmed by SDS-PAGE and Western blot analysis. The results on the cell lysate demonstrated the high expression of HA2 subunit of the influenza virus hemagglutinin. Conclusion: One of the disadvantages of the current flu vaccines is that they cannot produce efficient broad-spectrum cellular and humoral immune responses against all subtypes of the virus due to the genetic variation of the virus. Therefore, such a conserved protein is potentially a good candidate for production of a broad-spectrum vaccine to prevent influenza epidemics and pandemics.

Introduction: Due to the role of neutralizing antibodies which can prevent human cytomegalovirus (HCMV) infection, most of the efforts have been focused on designing vaccines capable of eliciting protective humoral immunity. The aim of this study was to evaluate the antibody response of BALB/c mice to a truncated HCMV glycoprotein B produced in insect cells using Baculovirus Expression Vector System (BEVS). Methods: The ectodomain of HCMV gB coding sequence was synthesized and the recombinant protein was expressed in Spodoptera frugipedra (Sf9) insect cell line using BEVS. The expression of the recombinant HCMV gB was verified using an HRP-conjugated polyclonal antibody, specific for HCMV gB. The levels of antibody responses and characterization of the subclasses of IgG antibodies were evaluated after vaccination of the mice. Results: The expression of truncated HCMV gB protein (~ 70 kDa) in the infected insect cells was verified by Western blot analysis. Measurement of IgG subclasses showed the dominance of IgG1 subclass response among all of the IgG subclasses (P < 0. 05) while the titers of IgG2a and IgG2b were approximately the same. Conclusion: This study demonstrated that BEVS could be used as an efficient approach for the expression of this truncated protein. The results also showed the use of this recombinant protein as a subunit vaccine could induce a significant antibody response, tilted toward IgG1.