Intranasal administration of immunogenic poly-epitope from influenza H1N1 and H3N2 viruses adjuvanted with chitin and chitosan microparticles in BALB/c mice.

OBJECTIVES: Prevalence of influenza virus, creates the need to achieve an efficient vaccine against it. We examined whether the predicted antigenic epitopes of HA, NP, and M2 proteins of the influenza H1N1 and H3N2 viruses accompanied by chitin and chitosan biopolymers might be relevant to the induction of effective proper mucosal responses. MATERIALS AND METHODS: The construct was prepared using B and T cell predicted epitopes of HA, NP, and M2 proteins from the influenza H1N1 and H3N2 viruses by considering haplotype "d" as a dominant allele in the BALB/c mice. Intranasal immunization with purified LPS free recombinant protein together with chitin and chitosan microparticles as adjuvants was administered at an interval of 2 weeks in thirty-five BALB/c female mice which were divided into seven groups. Ten days after the last immunization, humoral and cellular immune responses were examined. RESULTS: Elevated systemic IgG2a, IgA, and mucosal IgA revealed a humoral response to the construct. An increase in the number of IFN-γ-producing cells in re-stimulation of splenocytes in the culture medium by poly-tope as well as rise in the concentrations of IL-6, IL-17, and TNF-α along with the regulatory response of IL-10, presented the capacity of the designed protein to provoke significant immune responses. The neutralization test ultimately confirmed the high efficacy of the protein in inhibiting the virus. CONCLUSION: The results support the fact that immunogenic poly-tope protein in the presence of chitin and chitosan microparticles as mucosal adjuvants is able to induce humoral and cell-mediated responses in BALB/c mice.

PEGylated single-walled carbon nanotubes as co-adjuvants enhance expression of maturation markers in monocyte-derived dendritic cells.

Aim: This study investigated the application of phospholipid-PEGylated single-walled carbon nanotubes (PL-PEG-SWCNTs) as a safe co-adjuvant for the commercial recombinant hepatitis B virus vaccine to enhance induction of monocyte-derived dendritic cells (MDDCs) differentiation and activation in vitro as an immune response initiator cell to prompt a long-term immune response after a single dose injection. Methods: Immature MDDCs were exposed to PL-PEG-SWCNTs alone and in combination with hepatitis B vaccine. Results & conclusion: Study results confirm the enhanced expression of maturation markers in human immature MDDCs after PL-PEG-SWCNT exposure. The results suggest that PL-PEG-SWCNT is an efficient co-adjuvant for the commercial recombinant hepatitis B virus vaccine to enhance dendritic cell response stimulation in vitro.

The development and evaluation of a multi-epitope antigen as a serodiagnostic marker of Toxoplasma gondii infection.

BACKGROUND: Toxoplasma gondii (T. gondii) is a ubiquitous protozoan parasite which causes a serious disease called toxoplasmosis. The high prevalence of T. gondii infection has attracted a great deal of interest in its diagnosis and treatment. The use of pure antigens shows high sensitivity and specificity, but challenges such as cross-reactivity remain diagnostic difficulties. OBJECTIVES: The aim of this study was to use 3 surface antigens (SAGs) of T. gondii to design gene-encoding a multi-epitope and immunogenic protein as a serodiagnostic marker. MATERIAL AND METHODS: The multi-epitope antigen was expressed using Escherichia coli BL21 (DE3) cells and purified using affinity chromatography. To evaluate acute toxoplasmosis, 95 human sera with anti-T. gondii IgG, 25 human sera without anti-T. gondii IgG and 6 serum samples with nosocomial infections were collected and submitted to an enzyme-linked immunosorbent assay (ELISA) analysis. The potential of purified protein as a diagnostic marker of T. gondii infection was also investigated using ELISA analysis. RESULTS: The western blot analysis for both protein expression and purification confirmed that the protein was expressed and purified successfully. The results of validation showed a sensitivity of 72.6% and a specificity of 90.3% for recombinant ELISA. CONCLUSIONS: Although this protein showed potential for detecting T. gondii, the sensitivity and specificity were lower than in tests that use the whole body of the parasite.

Design and Development of Modified mRNA Encoding Core Antigen of Hepatitis C Virus: a Possible Application in Vaccine Production

Background: Hepatitis C virus (HCV) is a blood-borne pathogen, resulting in liver cirrhosis and liver cancer. Despite of many efforts in development of treatments for HCV, no vaccine has been licensed yet. The purpose of this study was to design and prepare a specific mRNA, without 5' cap and poly (A) tail transcribed in vitro capable of coding core protein and also to determine its functionality. Methods: Candidate mRNA was prepared by in vitro transcription of the designed construct consisting of 5ʹ and 3ʹ untranslated regions of heat shock proteins 70 (hsp70) mRNA, T7 promoter, internal ribosome entry site (IRES) sequences of eIF4G related to human dendritic cells (DCs), and the Core gene of HCV. To design the modified mRNA, the 5' cap and poly (A) tail structures were not considered. DCs were transfected by in vitro-transcribed messenger RNA (IVT-mRNA) and the expressions of green fluorescent protein (GFP), and Core genes were determined by microscopic examination and Western blotting assay. Results: Cell transfection results showed that despite the absence of 5' cap and poly (A) tail, the structure of the mRNA was stable. Moreover, the successful expressions of GFP and Core genes were achieved. Conclusion: Our findings indicated the effectiveness of a designed IVT-mRNA harboring the Core gene of HCV in transfecting and expressing the antigens in DCs. Considering the simple and efficient protocol for the preparation of this IVT-mRNA and its effectiveness in expressing the gene that it carries, this IVT-mRNA could be suitable for development of an RNA vaccine against HCV.

In-vitro Transcribed mRNA Delivery Using PLGA/PEI Nanoparticles into Human Monocyte-derived Dendritic Cells.

Induction of protein synthesis by the external delivery of in-vitro transcription-messenger RNA (IVT-mRNA) has been a useful approach in the realm of cell biology, disease treatment, reprogramming of cells, and vaccine design. Therefore, the development of new formulations for protection of mRNA against nucleases is required to maintain its activity in-vivo. It was the aim of the present study to investigate the uptake, toxicity, transfection efficiency as well as phenotypic consequences of a nanoparticle (NP) in cell culture. NP consists of poly D, L-lactide-co-glycolide (PLGA) and polyethyleneimine (PEI) for delivery of in-vitro transcription-messenger RNA (IVT- mRNA) encoded green fluorescent protein (GFP) in human monocyte-derived dendritic cells (moDCs). Nanoparticles that were synthesized and encapsulated with synthetic GFP mRNA, exhibited size distribution in this formulation, with mean particle sizes ranging between 415 and 615 nm. Zeta potential was positive (above 12-13 mV) and the encapsulation efficiency exceeded 73.5%. Our results demonstrated that PLGA/PEI NPs encapsulation of GFP mRNA had no toxic effect on immature monocyte-derived dendritic cells and was capable of delivering of IVT-mRNA into moDCs and was highly effective. The expression of GFP protein 48 h after transfection was confirmed by flow cytometry, microscopic examination and western blotting assay. This NP can make a way to target moDCs to express a variety of antigens by IVT- mRNA. The present study introduced the PLGA/PEI NP, which provided effective delivery of IVT-mRNA that encodes the GFP protein.

Using recombinant Chlamydia trachomatis OMP2 as antigen in diagnostic ELISA test.

BACKGROUND AND OBJECTIVES: The obligate intracellular bacterium Chlamydia trachomatis causes sexually transmissible diseases in human. Timely and sensitive detection of this pathogen is very important. There are many cross-reactions in bacteriological and serological methods in detection of this type of pathogens. The aim of this study was to achieve a more specific antigen for serological tests. MATERIALS AND METHODS: Blood samples were taken from 192 women with suspected chlamydial infection and sera were isolated. ELISA plate wells were coated with recombinant C. trachomatis OMP2 as antigen. Cut-off system was determined with 40 negative sera. The final results of this research were compared with Euroimmun commercial kit. RESULTS: The ELISA system cut-off was calculated at 0.27 using negative sera samples. ODs of positive samples were higher than 0.27 and negative samples were lower than it. We obtained 30 samples (15.62%) as positive and 162 cases (84.37%) as negative. Sensitivity and specificity of the recombinant antigen were 90% and 86%, respectively. This antigen showed no cross-reactivity with sera of patients infected with Hydatid cyst, HCV, Epstein barr virus, HBV, Helicobacter pylori, Toxoplasma gondii, Cytomegalovirus, Mycoplasma, Measles and Varicella zoster virus. CONCLUSION: The sensitivity and specificity of rOMP2 in ELISA for detection of C. trachomatis were 90% and 86%, respectively. Though the sensitivity was higher than results of Euroimmun commercial kit, its specificity was calculated lower than reference kit.

Salivary levels of secretary IgA, C5a and alpha 1-antitrypsin in sulfur mustard exposed patients 20 years after the exposure, Sardasht-Iran Cohort Study (SICS).

Sulfur mustard (SM) is a strong toxic agent that causes acute and chronic health effects on a myriad of organs following exposure. Although the primary targets of inhaled mustard gas are the epithelia of the upper respiratory tract, the lower respiratory tract is the focus of the current study, and upper tract complications remain obscure. To our knowledge there is no study addressing the secretory IgA (S-IgA), C5a, alpha 1 antitrypsin (A1AT) in the saliva of SM-exposed victims. In this study, as many as 500 volunteers, including 372 SM-exposed cases and 128 control volunteers were recruited. A 3 ml sample of saliva was collected from each volunteer, and the level of secretory IgA, C5a, and alpha 1 antitrypsin in the samples were compared between the two groups. The SM-exposed group showed a significantly higher amount of salivary alpha 1 antitrypsin and secretary IgA compared to the control group (p<.006 and p<.018 respectively). The two groups showed no significant difference (p=0.192) in the level of C5a. The results also showed that the level of salivary A1AT is more than that of IgA in severely injured cases. The findings presented here provide valuable insight for both researchers and practitioners dealing with victims of the chemical warfare agent, sulfur mustard. This research indicates that certain branches of the inflammatory processes mandate serious attention in therapeutic interventions.

Serum levels of GM-CSF 20 years after sulfur mustard exposure: Sardasht-Iran Cohort Study.

Sulfur mustard (SM) is highly toxic for various organs. The eyes, skin, respiratory tract, as well hematopoietic and immune systems are the main organs affected by SM. Granulocyte-macrophage colony stimulating factor (GM-CSF) is a potent cytokine that plays an important role in the hematopoietic and immune system. The aim of this study was to determine the serum levels of GM-CSF and its relation to blood cell count and other inflammatory cytokines 20 years after SM exposure. The association of GM-CSF with the clinical severity of pulmonary, ophthalmic and dermatologic complications has also been studied. In this historical cohort study named as Sardasht-Iran Cohort Study (SICS), 369 SM exposed male participants and 125 unexposed volunteers were studied. The serum concentrations of cytokines were measured by ELISA technique. The severity of clinical complications was graded according to the criteria verified by the Medical Committee of the Foundation of Martyr and Veterans Affairs. The serum levels of GM-CSF in the SM exposed group did not display any significant differences with the control group. Median of GM-CSF was 7.33 and 9.39 pg/ml in the SM exposed group and the controls respectively. There was a positive correlation between the serum levels of GM-CSF and the percent of eosinophils only in the exposed group. Moreover, positive correlations were found between circulating levels of GM-CSF with IL-1alpha, IL-1beta, TNF-alpha and IL-6. This correlation was not observed between GM-CSF and IL-8 in both study groups. The serum levels of GM-CSF did not show any significant association with clinical complications.

Serum soluble Fas ligand and nitric oxide in long-term pulmonary complications induced by sulfur mustard: Sardasht-Iran Cohort Study.

Sulfur mustard (SM) has short- and long-term toxicity against various organs including the respiratory system. However, the basic and molecular mechanisms of SM long-term toxicity have not clearly been defined. Thus, the aim of this study was to evaluate the association of soluble Fas ligand (sFasL) as well as nitric oxide (NO) serum levels with long-term pulmonary complications in a SM exposed population 20 years after SM exposure. In this historical cohort study 372 male SM exposed subjects and 128 age-matched unexposed controls were studied. Clinical evaluation and pulmonary function tests were carried out for all participants and serum concentrations of sFasL and NO measured. According to our results, the serum levels of sFasL and NO were not significantly different between the exposed and control groups. However, the serum levels of sFasL in the exposed group with pulmonary problems were significantly higher than their corresponding in the control group (116.711+/-81.166 vs 86.027+/-30.199 and p=0.028). Furthermore a significant elevation in sFasL levels was found in the exposed subjects with pulmonary problems compared to those exposed participants without pulmonary problems (116.711+/-81.166 vs 90.692+/-57.853 and p=0.004). Based on Global Initiative for chronic Obstructive Lung Disease (GOLD) classification analysis a positive correlation was observed between sFasL levels and pulmonary problems. There was also a significant negative correlation between sFasL and the white blood cell (WBC) count in the SM exposed cohort, but not in the control group. No significant association was shown between NO and pulmonary impairment in the SM exposed subjects. Thus, our results indicate that elevated serum levels of sFasL may be associated with progression of pulmonary diseases in the SM exposed subjects.

Comparison of QuantiFERON TB-G-test to TST for detecting latent tuberculosis infection in a high-incidence area containing BCG-vaccinated population.

OBJECTIVE: Until recently, the only tool for detection of latent tuberculosis infection (LTBI) was the tuberculin skin test (TST). QuantiFERON-TB Gold In-Tube test (QFT) is a promising in vitro diagnostic test for LTBI that has potential advantages over the TST. In this study we aimed to compare QFT with TST for diagnosis of LTBI. PATIENTS AND METHODS: A total of 186 BCG-vaccinated subjects enrolled in study. They underwent TST and QFT assay. They divided in two groups. Group 1 includes individuals who were at low risk for exposure to M. tuberculosis (LRG) and Group 2 includes individuals who were likely to have been exposed to M. tuberculosis infections (HRG). RESULTS: Overall agreement between QFT and TST was 89.3% (kappa = 0.052). In LRG, agreement between the two tests was 52.6% (95% confidence interval, 44-60%) with kappa-values of 0.019. In HRG agreement between the two tests was 63.2% (95% confidence interval, 42-84%) with kappa-values of 0.28. CONCLUSION: In conclusion, the QFT assay showed acceptable results for determining latent M. tuberculosis infection in vaccinated population. The decision to select QFT over TST will depend on the population, purpose of testing and resource availability.