جستجوی مقالات مرتبط با کلیدواژه « vaccine » در نشریات گروه « دامپزشکی »

Lactobacillus probiotic enriched diets can modulate host immune response. In this study, we investigated whether the three species Lactobacillus plantarum, L. bulgaricus and L. rhamnosus up-regulated two T-cells specific antigens and exerted the protective effect when administrated with formalin-killed Streptococcus agalactiae in Nile tilapia. For this purpose, a total of 180 Nile tilapia (average body weight 45.8 ± 22 g) were randomly divided into 6 experimental groups, i.e.: one control group and 5 vaccinated groups: Formalin killed cell (FKC); FKC+ Adjuvant; FKC+ L. plantarum; FKC+ L. bulgaricus and FKC+ L. rhamnosus. All groups were fed with normal commercial pellets and three groups were fed with pellets sprayed with three different lactobacilli. The results showed that the survival rate in the groups of Formalin killed cell (FKC) combined with oral administration of lactobacilli was from 70.0% to 75.0%.  Protection in the control group amounted to 31.3% illustrating a significant difference with other experimental groups. In this research, gene expression of CD4 and CD8 which have essential functions in the immune response quantified by qRT-PCR in the head kidney, skin, and spleen was reported in the form of fold change. The analysis of fold change (Mean ± SD) related to CD4 and CD8 at 30- and 60-days post-immunization (dpi) respectively showed an increase in fold change in all probiotic groups compared to the FKC group in two of which it was significant at the level of p<0.05. The results revealed that vaccination with FKC administrated lactobacilli-enriched diets increased the expression of genes related to immune response which can indicate higher protection against Streptococcus agalactiae in the probiotic groups compared with FKC vaccination alone similar to the results observed in FKC coupled with adjuvant vaccination.

Highly pathogenic avian influenza (HPAI) is a viral disease caused by some H5 and H7 subtypes of influenza virus type A in most species of birds, especially poultry. HPAI viruses are amongst the most challenging viruses that threaten both human and animal health. Consequently, various strategies such as the use of vaccines have been proposed to control the disease. After a catastrophic pandemic and the failure of conventional methods (elimination and extermination) in Iran, multiple vaccines has been used to control the disease. This study investigates the immunogenicity of two recombinant inactivated commercial vaccines of H5N1 and H5N3 subtypes in laying pullet flocks in Tehran Province, Iran. From 32 halls in 6 breeding units of laying pullets, 3200 sera and 800 tracheal and cloacal swabs were collected. After collecting the samples, Serum neutralisation (SN) and hemagglutination inhibition (HI) tests were conducted on sera to determine the serum titers of H5 specific antibody obtained from vaccine inoculation in three steps: before, after first vaccination and after the second vaccination (booster). SN and HI tests were carried out by the alpha and beta methods on the pooled samples by the vaccine type (as antigen for HI and SN), and the results were compared. The PCR was performed on the tracheal and cloacal swab samples to possibly detect the HA (H5)virus in the studied flocks. The HI test results showed that both vaccines had a Serum antibody titre above 5 (log2) after two vaccination rounds, indicating a desirable immunogenic response. The SN test results also showed a neutralisation index above 104.5 for both vaccines, indicating more than 50% reduction in antigenicity of the virus. The PCR results were negative. This study was the first investigation of immunogenicity following two-time vaccination against H5 subtype vaccines in Iranian poultry flocks, indicated suitable antibody titer against the influenza virus in vaccinated flocks.

Due to reduced levels of antibody provided by vaccines or the emergence of variants COVID-19 infections have re-emerged in many countries. A considerable supplementary intervention is recommended including an additional dose of vaccination. The present study aimed to investigate the predictors of the willingness to receivethe third dose of COVID-19 vaccine based on the health belief model (HBM) constructs among people referring to health centers in South Khorasan province. In this cross-sectional-analytical study, 283 people over 18 years in South Khorasan province were randomly selected by multi-stage cluster sampling method. The data were collected using a researcher-made questionnaire including demographic information and health status, knowledge about COVID-19 and the third dose of the vaccine, as well as a questionnaire on based HBM constructs through self-report. Finally, the data were analyzed using Chi-square, and multivariate logistic regression. The mean age of the study participants was 36.57±11.56 with range of 18-66 years. The results of multivariate logistic regression analysis showed that gender (P=0.012), marital status(P=0.038), occupation (P=0.013), and constructs of perceived severity (P=0.005), and cues to action (P=0.018), had a significant direct effect and the construct of perceived barriers (P=0.010) had a significant inverse effect on the willingness to acceptance the third dose of the vaccine. Also, the predictor variables explained about 67.7% of the tendency to receive the third dose of the vaccine. The current study suggests that enhancing the perceived severity of Covid-19, along with healthcareproviders recommendation to receive the vaccine and reducing perceived barriers, can effectivelyencourage individuals to receive the third dose of the Covid-19 vaccine. These findings can be utilized to develop interventions aimed at promoting the uptake of the booster dose of the Covid-19 vaccine.

The most extensive monkeypox outbreak in history commenced in 2022 and has swiftly disseminated globally. This review aims to succinctly outline host immune reactions to orthopoxviruses, present an insight into available vaccines to counteract the epidemic, and delve into clinical research and animal studies examining induced immunity against monkeypox induced via the vaccinia virus-based monkeypox vaccines. It addresses current concerns about the outbreak and suggests optimal vaccine utilization as a control measure. During the 1980s, surveillance studies in Central Africa and subsequent outbreaks demonstrated that smallpox vaccines were approximately 85% effective against monkeypox. These findings are substantiated by numerous animal studies, primarily in primates, involving live virus challenges through different inoculation methods, consistently showcasing high levels of protection and immunity post-vaccination. Smallpox vaccines emerge as effective countermeasures for managing monkeypox outbreaks, although they do entail adverse effects, and second-generation, replicative vaccines have prohibited usage. Third-generation vaccines pose a challenge for rapid responses as they require 2 doses, which can be difficult for people with weak immunity.  Insights from the COVID-19 outbreak must guide our collective approach to addressing the monkeypox outbreak and future outbreaks.

Purification is an important step in the production of viral vaccines that strongly affects product recovery and subsequent immune responses. The present study was carried out with the aim of improving the purification of infectious bursal disease virus (IBDV) by the tangential flow filtration (TFF) method. Then, the effect of the purified virus on the induction of immune responses against IBDV in specific pathogen free (SPF) chickens was investigated. The IBD07IR strain was propagated in embryonated SPF eggs. The virus was purified using a 100 kDa cassette. The quality of the recovered viruses was evaluated by titration. A total number of 60 SPF chickens were randomly divided into three groups (n = 20) and received the concentrated viral antigen, commercial live IBDV vaccine and phosphate-buffered saline at the age of 3 weeks by eye drop method. The bursa of Fabricius was examined histopathologically for possible changes. Sera were collected at 1-week intervals from day 0 until the end of 6 weeks after vaccination. The IBDV-specific antibody levels, induction of cell-mediated immunity and mRNA expression levels of cytokines were evaluated. The results showed that despite a relative raise in virus titer from 7.66 to 8.17 embryo infectious dose (EID)50 mL-1 following purification, both the purified IBDV and commercial vaccine are able to induce strong immune responses against the virus. Within a context of egg-based IBDV vaccine production, a single-step TFF can be applied for the relatively purification. This platform requires a further study in the selection of multiple membranes to optimize the operating conditions and final product.

In recent years, the hazardous use of antibiotic growth promotors in the poultry industry has led to the development of drug resistance and violative tissue residues. Therefore, the European Union Regulation banned application of these growth promotors, and the international authorities have searched for other natural and safe feed additive sources as substitutes for antibiotics. Chitosan has been used as a feed-additive alternative in veterinary medicine practices worldwide. Chitosan and chitosan-based nanoparticles have been extensively investigated in the poultry production system and have proved several positive impacts. The overall performance parameters of broilers and layers have been improved following dietary treatments with chitosan. Besides, chitosan showed antimicrobial activity against many bacterial, fungal, viral, and parasitic diseases as well as boosting of the immune response. Modulation of the antioxidant activity and modification of some blood parameters have also been detected owing to dietary chitosan supplementations. Moreover, chitosan nanoparticles have been now applied as a vaccine delivery vehicle and a mucosal adjuvant for many important poultry bacterial and viral diseases. Therefore, this review article sheds light on the effects of chitosan and its nanoparticle forms on the production traits of broilers and layers, their antimicrobial, immuno-regulatory, and antioxidant properties, as well as their effects on the blood constituents and vaccine production.

Due to its high prevalence and rapid spread, Newcastle disease is considered a deadly viral disease for the poultry industry worldwide. The uncontrolled and unplanned use of the Newcastle vaccine by poultry farmers reduces its protective value. This study aims to calculate the effectiveness of vaccination programs against Newcastle disease in Iranian broiler farms. The study method is analytical and case-control. One hundred two case farms and 102 control farms were selected for the study. The case farm was defined as a farm with losses exceeding 7%, accompanied by clinical criteria, post-mortem examination, molecular testing, and a history of regional disease outbreaks. The control farms had natural losses (below 7%) and no history of any disease in the current and previous periods. Control farms were matched with case farms regarding capacity, breed, and provincial distribution. The data were analyzed using the chi-square test and multivariable logistic regression analysis. The statistical software Stata version 14  was used for data analysis and modeling. According to the results, the use of the Vitapest strain vaccine by the spray method on day one, followed by the use of the inactivated vaccine by the injection method, and then two doses of the LaSota strain vaccine by the oral route in the program, (87% with a 95% confidence interval of  35-98%), the use of the inactivated vaccine by the injection method and two doses of LaSota strain vaccine by the oral route, (84% with a 95% confidence interval of 23-97%), the use of the inactivated Newcastle disease vaccine at the age of 7–12 days, (78% with a 95% confidence interval of 25-94%), and the use of the live vaccine against Newcastle disease with more than two doses in the program (66% with a 95% confidence interval of 15-88%) were effective. According to the results of this study, inactivated Newcastle disease vaccines are ineffective in the first week, and it is better to administer them at the ages of 7 to 12 days. It is also recommended to use spray vaccines of viscerotropic strains at one day of age to increase mucosal immunity against the Newcastle virus. Finally, principles of biosecurity and farm hygiene management should also be considered to achieve maximum vaccine effectiveness and have a consistent and regular program on the farm.

Aluminum-containing adjuvants are extensively used for inactive human and animal vaccines owing to their favorable immunostimulative and safe properties. Nonetheless, there is controversy over the effects of different aluminum salts as an adjuvant for the bovine parainfluenza virus type 3 (BPIV3) vaccine. In order to find a suitable adjuvant, we studied the effects of two adjuvants (i.e., aluminum hydroxide [Al(OH)3] and aluminum potassium sulfate [AlPO4]) on the production of neutralizing antibodies (NAbs) for an experimental BPIV3 vaccine. The animals under study (Guinea pigs) were randomly assigned to five groups of experimental vaccines containing Al(OH)3 (AH), AlPO4 (AP), Al(OH)3-AlPO4 mixture (MIX), commercial vaccine (COM), and control (NS). The treatment groups were immunized with two doses of vaccine 21 days apart (on days 0 and 21), and the control group received normal saline under the same conditions. The animals were monitored for 42 days, and blood samples were then taken. The results indicated that all vaccines were able to induce the production of NAbs at levels higher than the minimum protective titer (0.6). An increase in titer was observed throughout the monitoring period. Moreover, an increase in both the level and mean titer of NAbs obtained from the vaccine containing Al(OH)3 adjuvant was significantly higher than in the other studied groups (P≤0.005). The comparison of NAbs titer in other groups did not display a significant difference. Considering the speed of rising and the optimal titer of NAbs production in the experimental vaccine, the Al(OH)3 adjuvant is a suitable candidate for preparing a vaccine against BPIV3 for immunization.

Today, the human papillomavirus (HPV) L1 protein is the main target in the construction of prophylactic HPV vaccines. The production of virus-like particles (VLPs) that closely resemble the natural structure of the HPV16 virus and induce high levels of virus-neutralizing antibodies in animals and humans is facilitated by the expression of HPV16-L1 protein in eukaryotic cells. The Bac-to-Bac system has been previously used to produce high levels of recombinant proteins. In this study, we utilized this expression system to generate HPV16-L1 VLPs in Spodoptra frugipedra (Sf9) insect cells. The wild-type L1 gene of papillomavirus type 16 was selected from Gene Bank and placed in bacmid structure after codon optimization using pFast Bac vector. The recombinant baculovirus containing HPV-16/L1 gene was then provided using the Bac-to-Bac system. It should be mentioned that the vector was transfected into the Sf9 cell. The cells were then lysed and the expression of L1 protein was revealed by SDS-PAGE and confirmed by Western Blot. The L1 purification was performed through Ni-NTA chromatography. The VLP formation of papillomavirus L1 protein was visualized by transmission electron microscopy. The expressed recombinant L1 was ~60 KD on SDS-PAGE which was identified in western blot by a specific anti-L1 monoclonal antibody. The electron microscopy confirmed the assembly of VLPs. Results of this study showed that the production of this protein at the industrial level can be optimized using a baculovirus/Sf9 system. The characteristics and advantages of this system are promising and it is a suitable candidate for protein synthesis.

The development of proper immune responses to Newcastle disease (ND) vaccines is important in controlling the disease. Escherichia coli strain Nissle 1917 (EcN) is involved in regulating the immune system.

The current study evaluated the effects of EcN on immune responses to ND live vaccines in Japanese quails.

A total of 150 one-day-old quails were divided into three equal groups. Groups A and B received 107 and 106 CFU/ml/day of EcN, respectively, sprayed on their diets, while group C received 1 ml/day of PBS. All birds were vaccinated with B1 and Lasota vaccines at 10 and 20 days of age, respectively. Serum samples were collected in order to assay the levels of IgA and certain cytokines, including IL4, IFN-α, and IFN-γ, as well as antibody titers to NDV by HI and ELISA methods.

No significant difference (P>0.05) was observed in serum IgA and IFN-α levels among the groups. However, concentrations of IFN-γ and IL-4 in 42-day-old chicks in group A were significantly (P<0.05) higher than in both other groups. After 15 days of the second vaccination, the mean HI titer following NDV was significantly higher in group A than group C. Groups B and C showed significantly lower HI titer than group A after 22 days of the second vaccination. Mean ELISA titer to NDV was significantly (P<0.05) higher in group A than in groups B and C after 22 days of the second vaccination.

It seems that the spraying of 107 CFU/ml/day of EcN on quail diets enhances the immune response to NDV vaccines by increasing serum levels of IFN-γ and IL-4.

Adenoviral vectors (AdVs) are widely used as a gene delivery vehicle and vaccine design due to their genetic stability, transfer capacity of large genes, production at high titers, and remarkable efficacy of transduction. One of the most important applications of AdVs is in cancer immunotherapy. Tumor-associated antigens are overexpressed in cancer cells; however, they cannot induce immune responses sufficiently. Therefore, the immune system must be stimulated against these antigens to kill the cancer cells. This study described the construction steps of a recombinant AdV expressing human carcinoembryonic antigen (CEA) gene. Furthermore, in order to achieve a high titer of the virus, an efficient transfection was required. Three various transfection reagents were compared to achieve the best method of transfection. Carcinoembryonic antigen was cloned into the pAdV and transfected into the A293 cells using three different reagents, including polyethylenimine (PEI), calcium phosphate, and DMRIE-C. The PEI had the highest transfection efficiency, which was selected for the transfection of the recombinant plasmid. It has low toxicity for cells and is suitable for large-scale transfection. The virus produced in this study can be applied as a vaccine in cancer immunotherapy for stimulating the immune system against CEA-expressing tumors.