Avian Vaccine Research Articles

The potency of newly development H5N8 and H9N2 avian influenza vaccines against the isolated strains in laying hens from Egypt during 2019.

Avian influenza (AI) is a respiratory disease complex syndrome recently recorded in vaccinated flocks causing high economic losses. This study aimed to prepare inactivated vaccine from recently isolated field strains [highly pathogenic avian influenza (HPAI) (H5N8) and low pathogenic avian influenza (LPAI) (H9N2)] and compare the efficiency of the two experimental avian influenza vaccines and some commercial avian influenza H5 and H9N2 vaccines in laying hens. The obtained results indicated that the identified experimental vaccines (H5N8 and H9N2) were protected the flocks from AI as compared to commercial H5N1, H5N3, and H9N2 vaccines, which showed a protection level of 80, 70, and 90%, respectively, indicating a high efficacy for the developed vaccines. In addition, it significantly improved the virus shedding, especially when used in booster dose. The experimental vaccines were given high antibody titer higher than commercial vaccine which was reached to 9.3 log2, 9.7log2 for experimental H5N8 vaccine which was significantly higher than and groups 3 and 4 especially at 2nd WPV, while at the 3rd WPV, the significant difference was with group 4 only. The HI titer was 9.3 log2 at 2nd WPV for the experimental H9N2 vaccine that was significantly higher than group 9. In conclusion, the booster dose of the experimental vaccines could elicit strong immunity than single-dose and commercial vaccines.

Evaluation of Cholera Toxin Adjuvanticity Effect on the Production of Specific Antibodies Induced by Avian Infectious Bronchitis Vaccine in Chickens.

Cholera toxin (CT) is one of the most well-known immunostimulants. Mammalian studies have shown that CT can generate immune responses against antigen. However, it has not exhibited a definite effect on poultry yet. In this study, focusing on a cost-effective method, the effect of different concentrations of CT obtained from Vibrio cholerae biotype El Tor and serotype Inaba was investigated on the immunogenicity of infectious bronchitis vaccine. After culturing and concentrating CT, different concentrations of CT (0.1, 1, 2, and 5 micrograms) were combined with avian infectious bronchitis vaccine strain H120 produced by Razi Vaccine and Serum Research Institute (RVSRI) and, at 7 days of age, inoculated via the eye drop administration in 42 specific-pathogen-free chickens (seven groups of six chicks that included four experimental groups, two negative control groups (PBS and toxin), and one positive control group). Blood samples were taken weekly from the wing veins of the chickens, and the immunoglobulin G (IgG) titer was checked by enzyme-linked immunosorbent assay. The results showed that 2 µg of CT in comparison with other concentrations caused a significant increase in the antibody titer against avian infectious bronchitis in the blood serums of the chickens. One-way ANOVA test showed that all the results of this study were significant at P<0.05 level. Our data show that CT has the potential to further stimulate the immune system of chickens and may increase the immunogenicity of the infectious bronchitis vaccine. However, more research is needed to examine all aspects of the use of this toxin in animal vaccines.

A broad spectrum HVT-H5 avian influenza vector vaccine which induces a rapid onset of immunity

Current methods to combat highly pathogenic avian influenza (HPAI) outbreaks in poultry rely on stamping out and preventive culling, which can lead to high economic losses and invoke ethical resistance. Emergency vaccination could be an alternative as vaccination is one of the most efficient and cost-effective measures to protect poultry from HPAI infection, preventing spreading to other poultry and greatly reducing the potential transmission to humans. Current conventional inactivated AI vaccines may be useful for combating AI outbreaks, but do not fulfil all targets of an ideal AI vaccine, including mass applicability and rapid onset of immunity. We aimed to further investigate the potential of Herpesvirus of Turkeys (HVT) as a vector containing a recombinant H5 hemagglutinin of HPAI H5N1. This HVT-H5 vector was analysed in vitro, tested for onset of immunity against AI challenge, breadth of protection, reduction of virus shedding, and induction of both antibody and cellular responses in SPF layers or broiler chicks containing maternal derived antibodies (MDA+). In SPF layers HVT-H5 provided full protection to lethal challenges with 4 antigenically diverse HPAI H5N1 strains from 2 weeks post vaccination (w.p.v.), while in MDA+ birds full protection was provided from 3 w.p.v. to homologous challenge. Also shedding of challenge virus was reduced in both SPF and MDA+ birds. HVT-H5 induced a protective HI titre (≥4) to 11 HPAI H5N1 strains at 3 w.p.v. in 3-week-old SPF layers and to HPAI H5N8 A/ch/Neth/14015531/2014. Besides inducing a protective antibody response HVT-H5 also induced an influenza-specific T cell response. This data demonstrates that HVT-H5 vaccine appears to fulfil many of the criteria for an ideal AI vaccine including early onset of immunity, a broad protection, reduced virus shedding, protection in presence of AI-MDA and could be a useful tool in the combat of AI outbreaks worldwide.

Avian Influenza-Killed Vaccine on Tissue Distribution and Shedding of Avian Influenza Virus H9N2 in Ducklings.

Ducks play an important role in the transmission of avian influenza to poultry farms. Because of the importance of vaccination in reducing virus shedding, this study evaluated avian influenza-killed vaccine H9N2 on tissue distribution and shedding of avian influenza virus H9N2 in ducklings. One hundred-day-old ducklings were purchased and, after bleeding from 20 birds, were kept in four separate rooms under standard conditions. Groups 1 and 2 were vaccinated at 9 days, and groups 2 and 3 were challenged with 0.1 ml of allantoic fluid containing 105 EID50 (A/chicken/Iran/Aid/2013(H9)) virus intranasally at 30 days. Group 4 chicks were kept as the control group. Chicks were observed two times daily. On days 1, 3, 5, and 8 after inoculation, 3 chicks were randomly selected from each group and cloaca and trachea swabs samples were collected from each bird. Then the ducklings were euthanized and trachea, lung, spleen, intestine, liver, and brain tissue samples were collected for molecular detection. The virus was detected in the tissues and tracheal and cloacal swabs by polymerase chain reaction (PCR), and anti-AIV titres were measured by HI test. The results showed no clinical signs in the challenged groups. In the vaccinated challenged group, virus was detected only in cloacal swabs, but in the unvaccinated challenged group, virus was detected more in tracheal swabs than in cloacal swabs. In challenged-unvaccinated chicks, virus was detected in the trachea and lungs, and in challenged-vaccinated birds, virus was detected in the intestines. In conclusion, vaccinating ducks against the AI H9N2 virus reduced shedding and tissue distribution of AI viruses in challenged ducks.

Novel Inactivated Subtype B Avian Metapneumovirus Vaccine Induced Humoral and Cellular Immune Responses.

Avian metapneumovirus (aMPV), a highly contagious agent, is widespread and causes acute upper respiratory tract disease in chickens and turkeys. However, currently, there is no vaccine licensed in China. Herein, we describe the development of an inactivated aMPV/B vaccine using the aMPV/B strain LN16. Combined with a novel adjuvant containing immune-stimulating complexes (ISCOMs), the novel vaccine could induce high virus-specific and VN antibodies. In addition, it activated B and T lymphocytes and promoted the expression of IL-4 and IFN-γ. Importantly, boosting vaccination with the inactivated aMPV/B vaccine could provide 100% protection against aMPV/B infection with reduced virus shedding and turbinate inflammation. The protection efficacy could last for at least 6 months. This study yielded a novel inactivated aMPV/B vaccine that could serve as the first vaccine candidate in China, thus contributing to the control of aMPV/B and promoting the development of the poultry industry.

Evaluation of Serum Conversion Induced by Infectious Bursal Disease Vaccines Submitted to Official Quality Control in the Period 2013 to April 2014

The prophylaxis of many avian diseases is based on measures of biosecurity and active immunization using live vaccines. One of the most important tests for vaccine quality control is a serum conversion. Serum conversion is performed to check the production of certain virus, after immunization. The Avian Health Unit at LFDA-SP carries out the quality control of commercially available avian vaccines in Brazil. The aim of the study was to evaluate the results of serum conversion of live monovalent vaccines and complex Infectious Bursal Disease vaccines (IBDV) in the period of 2013 to April/2014. Twelve batches of live monovalent vaccines belonging to seven laboratories were tested and 16 batches of immune complex vaccines belonging to two laboratories.

Haemagglutinin displayed on the surface of Lactococcus lactis confers broad cross-clade protection against different H5N1 viruses in chickens

BackgroundThe highly pathogenic avian influenza (HPAI) H5N1 virus poses a potential threat to the poultry industry. The currently available avian influenza H5N1 vaccines for poultry are clade-specific. Therefore, an effective vaccine for preventing and controlling H5N1 viruses belonging to different clades needs to be developed.ResultsRecombinant L. lactis/pNZ8148-Spax-HA was generated, and the influenza virus haemagglutinin (HA) protein of A/Vietnam/1203/2004 (H5N1) was displayed on the surface of Lactococcus lactis (L. lactis). Spax was used as an anchor protein. Chickens vaccinated orally with unadjuvanted L. lactis/pNZ8148-Spax-HA could produce significant humoral and mucosal responses and neutralizing activities against H5N1 viruses belonging to different clades. Importantly, unadjuvanted L. lactis/pNZ8148-Spax-HA conferred cross-clade protection against lethal challenge with different H5N1 viruses in the chicken model.ConclusionThis study provides insights into the cross-clade protection conferred by unadjuvanted L. lactis/pNZ8148-Spax-HA, and the results might help the establishment of a promising platform for the development of a safe and effective H5N1 cross-clade vaccine for poultry.

Efficacy of a novel avian metapneumovirus live vaccine candidate based on vaccination route and age

This article describes a series of animal studies for the development of an avian metapneumovirus (aMPV) live vaccine. Although aMPV causes continual economic loss in the poultry industry, there are no live aMPV vaccines available in Korea. Furthermore, information is limited with respect to standard field practices for vaccinations at an early age. Here, the development of an aMPV live vaccine was attempted, and its efficacy was investigated with respect to the vaccination route and age to develop a method for controlling aMPV. Before vaccine development, an animal challenge model was established using the aMPV field isolate to identify the most effective time and site for collecting samples for evaluation. After attenuation of the virulent aMPV in Vero cells, a safety and efficacy test was conducted for the vaccine candidate. As a novel aMPV live vaccine candidate, aMPV K655/07HP displayed sufficient safety in day-old chicks with 10 vaccine doses. The efficacy test using 1-week-old chicks showed weaker humoral immune response than that in 4-week-old chicks. However, the candidate vaccine provided complete protection against infection caused by the challenge virus for all ages of vaccinated chicks. In conclusion, an effective aMPV challenge model was established for studying aMPV in chickens, which offered important, insightful information. The safety and efficacy study suggested that the new aMPV candidate vaccine could be used to effectively reduce the economic losses incurred because of aMPV infection.

Efficacy of commercial polyvalent avian infectious bronchitis vaccines against Chinese QX-like and TW-like strain via different vaccination strategies

The infectious bronchitis virus (IBV) is an acute and highly contagious disease, which affects chickens of all ages. Vaccination is the most important way to control this disease. Nevertheless, novel variant strains are constantly reported because of the lack of proofreading capabilities of RNA polymerase and high frequency of homologous RNA recombination. Cross-protection studies has demonstrated that the vaccines could provide great protective effects against viruses of same serotype or genotype. However, the protective effect of different commercial vaccines and vaccine combinations against the prevalent IBV strains in China has rarely been studied. Owing to the multiple genotype or serotype IBV strains prevalence in China, the polyvalent vaccines and their composition were used to expanding the protection spectrum of vaccine in practical application. To evaluate the protection of Chinese commercial IBV polyvalent vaccines against prevalent strains (QX-like and TW I-like), an immune challenge test was conducted. Four polyvalent vaccines, containing 4/91, H120, YX10p90, LDT3-A, and 28/86, were combined to form 8 vaccination strategies, almost all of which could provide more than 70% protection effects against challenge with QX-like strain. Particularly, the best protection rate (93%) was generated by administration the polyvalent vaccine C (H120 + 28/86 + 4/91) at 1 D of age and the polyvalent vaccine B (H120 + 4/91 + YX10p90) at 10 D of age. However, all the vaccination strategies in this study cannot provide great protective effects against TW-like strain, and more vaccines should be included in studies to expand the protection spectrum of vaccine. Therefore, for the newly emerging IBV strains, immunization with polyvalent vaccines via different vaccination strategies could be used to control the prevalence of IBV in a short time, whereas developing the homologous vaccines was not always necessary.

Comparative Protective Efficacies of Novel Avian Paramyxovirus-Vectored Vaccines against Virulent Infectious Bronchitis Virus in Chickens.

Viral vectored vaccines are desirable alternatives for conventional infectious bronchitis virus (IBV) vaccines. We have recently shown that a recombinant Newcastle disease virus (rNDV) strain LaSota expressing the spike (S) protein of IBV strain Mass-41 (rLaSota/IBV-S) was a promising vaccine candidate for IBV. Here we evaluated a novel chimeric rNDV/avian paramyxovirus serotype 2 (rNDV/APMV-2) as a vaccine vector against IBV. The rNDV/APMV-2 vector was chosen because it is much safer than the rNDV strain LaSota vector, particularly for young chicks and chicken embryos. In order to determine the effectiveness of this vector, a recombinant rNDV/APMV-2 expressing the S protein of IBV strain Mass-41 (rNDV/APMV-2/IBV-S) was constructed. The protective efficacy of this vector vaccine was compared to that of the rNDV vector vaccine. In one study, groups of one-day-old specific-pathogenic-free (SPF) chickens were immunized with rLaSota/IBV-S and rNDV/APMV-2/IBV-S and challenged four weeks later with the homologous highly virulent IBV strain Mass-41. In another study, groups of broiler chickens were single (at day one or three weeks of age) or prime-boost (prime at day one and boost at three weeks of age) immunized with rLaSota/IBV-S and/or rNDV-APMV-2/IBV-S. At weeks six of age, chickens were challenged with a highly virulent IBV strain Mass-41. Our challenge study showed that novel rNDV/APMV-2/IBV-S provided similar protection as rLaSota/IBV-S in SPF chickens. However, compared to prime-boost immunization of chickens with chimeric rNDV/APMV-2, rLaSota/IBV-S and/or a live IBV vaccine, single immunization of chickens with rLaSota/IBV-S, or live IBV vaccine provided better protection against IBV. In conclusion, we have developed the novel rNDV/APMV-2 vector expressing S protein of IBV that can be a safer vaccine against IB in chickens. Our results also suggest a single immunization with a LaSota vectored IBV vaccine candidate provides better protection than prime-boost immunization regimens.

Efficacy of Live Attenuated Vaccine and Commercially Available Lectin Against Avian Pathogenic E. coli Infection in Broiler Chickens.

In this study, the protective efficacy of an E. coli live attenuated vaccine was compared to the preventive administration of lectin preparation before the challenge. Two hundred broiler chicks were divided into eight equal groups. The first group was used as a negative control group. Three groups were vaccinated at day 1 with the avian colibacillosis live vaccine of which one group served as a vaccinated nonchallenged group. Another two groups were treated with lectin product (0.5 mL/L drinking water) for three days before the challenge. The last two groups served as challenge control for either E. coli O78 or O125 strains. The challenge was conducted at three weeks of age with either homologous O78 or heterologous O125 E. coli strains, using 0.5 mL/bird of each avian pathogenic E. coli (APEC) strain (~108 colony forming units “CFU”/mL)/subcutaneously. The bodyweight and feed conversion ratios (FCR) were calculated for four weeks. Clinical signs and gross and histopathological lesions were scored at two and seven days post inoculation (dpi). The heart and liver of euthanized chickens at 2 dpi were removed aseptically and homogenized to evaluate pathogenic E. coli colonization. Results showed that live avian colibacillosis vaccine reduced mortalities and APEC colonization in the homologous challenge group but not in the heterologous challenge group. Lectin-treated groups showed 20% and 16% mortality after challenge with E. coli O78 and O125, respectively, and both groups showed performance parameters, clinical signs, and histopathological lesion scores comparable to the negative control group, with variable E. coli colonization of heart and liver. The study demonstrated the efficacy of live attenuated avian colibacillosis vaccine against homologous but not heterologous APEC challenge in broiler chickens. The lectin-containing products can be used as a preventive medication to reduce the clinical impacts of colibacillosis regardless of the challenge strain. Standardization of the evaluation parameters for APEC vaccines is recommended.

Protein Fraction Profiles on Dry Holstein Cows Vaccinated Using H5N1 Avian Influenza Vaccine

The objective of this experiment was to study the effect of H5N1 avian influenza vaccination on protein fraction profiles of pregnant cows. Dry Holstein cows, clinically healthy, were divided into two groups, control (n=3) and vaccinated (n=7). The vaccinated group were injected by commercial killed avian influenza H5N1 vaccine subcutaneously, four doses/head, three times every two weeks. Blood samples were collected from the coccygeal vein, starting before the 1st vaccination, repeated every two weeks until calving for the concentration of total protein, albumin, and globulin analysis. Results of this experiment showed that there were no differences in total protein, albumin, and globulin concentration between groups and time of vaccination (P>0.05). In conclusion, the vaccination on dry Holstein cows using commercial killed avian influenza H5N1 vaccine three times before calving does not influence the profiles of protein fraction.

A 25-Year-Old Sample Contributes the Complete Genome Sequence of Avian Coronavirus Vaccine Strain ArkDPI, Reisolated from Commercial Broilers in the United States.

Here, we report the complete genome sequence of Avian coronavirus strain ArkDPI of the GI-9 lineage, isolated from broiler chickens in North Georgia in 1994. This is the complete genome sequence of this vaccine strain, reisolated from broilers in the United States.

Use of degenerate oligonucleotide primed polymerase chain reaction for detection of chicken anaemia virus contamination in avian viral vaccines

For quality control of biologicals of veterinary use, the absence of extraneous agents needs to be certified. One of the requirements for quality control of avian viral vaccines is to demonstrate freedom from extraneous and adventitious pathogenic agents, like chicken anaemia virus (CAV). In this study, a degenerate oligonucleotide primed PCR (DOP-PCR) for the detection of CAV was developed. Degenerate oligonucleotide primers were selected based on sequences corresponding to conserved regions of VP1 gene. After spiking of CAV genomic DNA to an infectious laryngotracheitis virus (ILTV) vaccine, detection limit for the test was 3.056×10-9 ng/µl. To evaluate the performance of the test, 11 avian viral vaccines including infectious bronchitis virus (IBV), newcastle disease virus (NDV), infectious bursal disease virus (IBDV) and ILTV vaccines from 5 manufacturers were screened for CAV and no contamination was detected. The test described here may provide a rapid, sensitive and specific method for contamination detection of avian viral vaccines with CAV, and may be applied for quality control of live and killed commercial vaccines.

Primary cell culture of zebrafish (Danio rerio) as a material for developing H5N1 avian influenza vaccines

In recent decades, zebrafish (Danio rerio) has been widely used as a model of biological experiments not only in the immunology and oncology aspects but also experimental animals for infectious diseases in human and fishes. The virus used in this study was the H5N1 avian influenza reverse genetic virus obtained from the Professor Nidom Foundation, Surabaya, Indonesia. We revealed that TCID50 was 3.1623*107/mL, then the virus was developed by inoculating into the primary cell culture and we performed HA test. Samples that showed positive results on the HA test then performed RNA extraction and confirmed by one-step RT-PCR. It can be seen from the presence of cytopathogenic effects (CPE) in primary cell cultures and also can be seen from HA titers in viral harvest samples from the primary cells of zebrafish (Danio rerio) that shows the same result of HA titers is 28. In conclusion, the present study demonstrated that there is an alternative development of new primary cell sources which leads to halal aspects of the production of avian influenza H5N1 vaccines.

Detection and characterization of endogenous avian leukosis virus obtained from contaminated avian vaccines

Detection and characterization of endogenous avian leukosis virus obtained from contaminated avian vaccines

Coupling metabolomics analysis and DOE optimization strategy towards enhanced IBDV production by chicken embryo fibroblast DF-1 cells

Infectious bursal disease (IBD) caused by IBD virus (IBDV) is highly contagious viral and vaccination in chicken embryo has been an effective mean to prevent acute infection. However, the current production of IBDV vaccine faces serious batch instability and external contamination. The chicken embryonic fibroblast cell line DF-1 is widely used for the proliferation of avian viruses and vaccine production. Thus, optimizing the production of IBDV by DF-1 cells has an important application value. Combining metabolomics analysis and a Design of Experiments (DOE) statistical strategy, this study successfully optimized the process of IBDV production by DF-1 cells. Differential analysis and time series analysis of metabolite data in both IBDV-infected and uninfected DF-1 cells were performed by multivariate statistical analysis. The results showed that the intracellular metabolite intensities of glycolysis, the pentose phosphate pathway, the nucleoside synthesis pathway, lipid metabolism, and glutathione metabolism were upregulated, and the TCA cycle underwent a slight downregulation after IBDV infection of DF-1 cells. Based on the metabolome results and DOE statistical optimization method, the additive components suitable for IBDV proliferation were determined. The IBDV titer increased by 20.7 times upon exogenous addition of cysteine, methionine, lysine and nucleosides in the control medium, which is consistent with the predicted result (20.0 times) by a multivariate quadratic equation. This study provides a strategy for the efficient production of IBDV vaccines and could potentially be utilized to improve the production of other viral vaccines and biologics.

Current Progress of Avian Vaccines Against West Nile Virus.

Birds are the main natural host of West Nile virus (WNV), the worldwide most distributed mosquito-borne flavivirus, but humans and equids can also be sporadic hosts. Many avian species have been reported as susceptible to WNV, particularly corvids. In the case that clinical disease develops in birds, this is due to virus invasion of different organs: liver, spleen, kidney, heart, and mainly the central nervous system, which can lead to death 24–48 h later. Nowadays, vaccines have only been licensed for use in equids; thus, the availability of avian vaccines would benefit bird populations, both domestic and wild ones. Such vaccines could be used in endangered species housed in rehabilitation and wildlife reserves, and in animals located at zoos and other recreational installations, but also in farm birds, and in those that are grown for hunting and restocking activities. Even more, controlling WNV infection in birds can also be useful to prevent its spread and limit outbreaks. So far, different commercial and experimental vaccines (inactivated, attenuated, and recombinant viruses, and subunits and DNA-based candidates) have been evaluated, with various regimens, both in domestic and wild avian species. However, there are still disadvantages that must be overcome before avian vaccination can be implemented, such as its cost-effectiveness for domestic birds since in many species the pathogenicity is low or zero, or the viability of being able to achieve collective immunity in wild birds in freedom. Here, a comprehensive review of what has been done until now in the field of avian vaccines against WNV is presented and discussed.

A Novel Vaccine Strategy to Overcome Poor Immunogenicity of Avian Influenza Vaccines through Mobilization of Memory CD4 T Cells Established by Seasonal Influenza.

Avian influenza vaccines exhibit poor immunogenicity in humans. We hypothesized that one factor underlying weak B cell responses was sequence divergence between avian and seasonal influenza hemagglutinin proteins, thus limiting the availability of adequate CD4 T cell help. To test this, a novel chimeric hemagglutinin protein (cH7/3) was derived, comprised of the stem domain from seasonal H3 hemagglutinin and the head domain from avian H7. Immunological memory to seasonal influenza was established in mice, through strategies that included seasonal inactivated vaccines, Flumist, and synthetic peptides derived from the H3 stalk domain. After establishment of memory, mice were vaccinated with H7 or cH7/3 protein. The cH7/3 Ag was able to recall H3-specific CD4 T cells, and this potentiated CD4 T cell response was associated with enhanced early germinal center response and rapid elicitation of Abs to H7, including Abs specific for the H7 head domain. These results suggest that in pandemic situations, inclusion of CD4 T cell epitopes from seasonal viruses have the potential to overcome the poor immunogenicity of avian vaccines by helping B cells and conferring greater subtype-specific Ab response to viral HA.

In This Issue

Abstract IL-33 during Early B Cell Development See article p. 1457 Distinct Development of Fetal and Adult Vγ9Vδ2 T Cells See article p. 1468 Helping CD4 Memory in Avian Flu Vaccination See article p. 1502 Recruiting STING to the ER See article p. 1560 Trim58 Trims TLR2 in Colitis See article p. 1636