Fowlpox Research Articles

Avipoxvirus in Egypt and African continent: A review

Fowl pox disease is a slow-spreading viral infection of wild and domesticated birds of both genders, all ages and breeds. The disease occurs in two distinct forms; the more common cutaneous or dry form and the less common diphtheritic form. Fowl poxvirus (FWPV) is a member of the Avipoxvirus (APV) and it is one of the greatest challenges facing the poultry industry, its incidence is higher in tropical and subtropical countries. It causes a significant level of morbidity and increased mortality, especially in the diphtheritic form which may reach to 50%. Avipoxvirus has been recorded in Egypt and Africa in the early of 1960, since then, it has been recorded in variable domesticated and wild bird species in different countries and Governorates. The free-living and wild birds represent a potential threat and source of infection for the domesticated poultry species. In the last ten years, the phylogenetic analysis of the partial genome sequences has gained insight into the evolutionary biology of APV in Africa. One of the main characters of APV is relative genetic stability, especially in fpv167 region of the genome. This area of the genome clustered the APV of chicken and turkey origin phylogenetically into fowl poxvirus subclade A1 together with other avipoxviruses (APVs) isolated from Galliformes worldwide. However, the pigeon poxviruses phylogenetically belong to subclade A2 with other APVs isolated from Columbiformes worldwide. The analysis of the fpv140 region provides a further comprehensive taxonomic classification based on the virus-host origin and distribution, especially in the case of the pigeon poxvirus (PGPV), which clustered separately into different subclades according to their geographical distribution. This review focus on the origin, distribution, classification and taxonomy of APVs circulating in Egypt mainly with a brief report on the situation of APVs in the other neighboring.

Assessment of farmer opinions on vaccination of village chickens against Newcastle disease and its benefit in eight communities in Bauchi State, Nigeria

Newcastle disease (ND) is a major limitation to the production, consumption and sales of village chickens in Africa. A pagrticipatory proportional piling exercise was conducted among village chicken farmers selected during focus group discussions held in eight communities in Bauchi State to assess their opinions on vaccination of their village chickens with thermostable Newcastle disease vaccine I-2 (I-2 NDV) and its benefits. The assessment involved 64 participants (8 from each community) whose chickens had received two I-2 NDV three months apart and 12 participants whose chicken had received only one I-2 NDV. Of the 64 farmers who initially were selected and had volunteered to participate in the study, two of the participants were not available to give their opinion on the importance and benefit of vaccination; while, eight of participants did not think the vaccine is important and have chosen not to participate in the assessment exercise. The remaining 54 participants had endorsed the vaccine with a total score of 100% (270/270). They also awarded 91.3% (283/310) of their scores to flock increase due to reduced mortality by I-2 NDV with the remaining 8.7% (27/310) of the scores indicating no flock increase. A probing of the reason why some of these farmers did not experience flock increase revealed the occurrence of fowl pox disease that has killed some of their chickens. The scores from participants whose chicken had received only one vaccine was 100% for both endorsement of the vaccine (60/60) and observation of flock increase (60/60). The study highlights I-2 NDV as an appropriate vaccine that could be used to control ND in village chickens in Bauchi State and beyond. Keywords : Newcastle disease, Thermostable Newcastle disease vaccine (I-2), Village chickens, Bauchi State, Nigeria

Selenium, Selenoproteins and Viral Infection.

Reactive oxygen species (ROS) are frequently produced during viral infections. Generation of these ROS can be both beneficial and detrimental for many cellular functions. When overwhelming the antioxidant defense system, the excess of ROS induces oxidative stress. Viral infections lead to diseases characterized by a broad spectrum of clinical symptoms, with oxidative stress being one of their hallmarks. In many cases, ROS can, in turn, enhance viral replication leading to an amplification loop. Another important parameter for viral replication and pathogenicity is the nutritional status of the host. Viral infection simultaneously increases the demand for micronutrients and causes their loss, which leads to a deficiency that can be compensated by micronutrient supplementation. Among the nutrients implicated in viral infection, selenium (Se) has an important role in antioxidant defense, redox signaling and redox homeostasis. Most of biological activities of selenium is performed through its incorporation as a rare amino acid selenocysteine in the essential family of selenoproteins. Selenium deficiency, which is the main regulator of selenoprotein expression, has been associated with the pathogenicity of several viruses. In addition, several selenoprotein members, including glutathione peroxidases (GPX), thioredoxin reductases (TXNRD) seemed important in different models of viral replication. Finally, the formal identification of viral selenoproteins in the genome of molluscum contagiosum and fowlpox viruses demonstrated the importance of selenoproteins in viral cycle.

Field safety and efficacy of a unique live virus vaccine for controlling avian encephalomyelitis and fowlpox in poultry.

Background and Aim:Infection of commercial poultry with avian encephalomyelitis (AE) and fowlpox (FP) virus causes heavy economic loss in endemic areas. Although vaccines are routinely used to control these two diseases, the problem still persists almost all over the world. This study aimed to evaluate safety and efficacy of a unique AE + FP + pigeon pox (PP) live virus vaccine in layer-type chickens under both laboratory and field conditions.Materials and Methods:The study was conducted using 289 specific-pathogen-free (SPF) chickens under the laboratory conditions and 185,648 commercial layer-type chickens under field conditions. In two consecutive laboratory trials, 8-week-old SPF chickens were vaccinated with the AE + FP + PP live virus vaccine through wing web route and challenged against virulent strains of FP and AE viruses at 3-week post-vaccination (WPV). Challenged chickens were observed for disease protection for 10-21 days. For field safety trials, commercial layer-type chickens in three different geographical areas in the USA were vaccinated with the AE + FP + PP vaccine and observed daily up to 21 days for vaccine “take,” adverse reactions, and mortality.Results:The vaccine was found safe and efficacious under both laboratory and field conditions. Vaccine “take” and protection against FP challenge were 100%. Average protection against AE challenge was 97%. Mean AE enzyme-linked immunosorbent assay (ELISA) antibody titer in the field vaccinated chickens was >1200 at 10 WPV. Average daily post-vaccination mortality in the field vaccinated chickens was 0.04%. So far, more than 400 million chickens in the USA have been vaccinated with this vaccine. No vaccine-associated adverse reactions, other safety issues, or immunity breakdown cases in the vaccinated flocks due to field virus infection have been reported.Conclusion:This unique vaccine containing AE, FP, and PP viruses in a single preparation was found to be safe and efficacious in controlling the diseases caused by the virulent field strains of AE and FP. Besides being safe and efficacious, this vaccine also offered distinct advantages over the traditional vaccination practices in controlling these two diseases in poultry.

Insights into pathological and molecular characterization of avipoxviruses circulating in Egypt

ABSTRACT 1. Avipoxvirus (APV) infections are one of many threats inflicting economic losses within the poultry industry, particularly in tropical and subtropical countries. A proper and comprehensive study for APVs is needed to increase the knowledge concerning the diversity and evolution of the virus. 2. For this purpose, 136 bird flocks of different species and breeding types were examined for APV infection between October 2016 and November 2017. One hundred and thirty samples had visible pocks on the chorioallantoic membrane (CAM) which were designated as fowl pox-like viruses via amplification of 578 bp from the P4b gene and 1800 bp from the fpv140 locus. 4. A comprehensive phylogenetic analysis of fpv167 locus (P4b), fpv140 locus (fpv139 and fpv140) and fpv94 (DNA polymerase) revealed that all the analysed strains belong to fowl pox-like viruses (clade A; subclade A1 and A2). Based on the fpv140 locus full nucleotide sequence, three turkey originated strains were seen to be divergent from chicken originated sequences and branched into novel subclade A1.b. 5. Trees comparison, within the term of speculation of virus-host specificity, clearly highlighted a high order specific subgrouping among subclades in the case of the fpv140 locus (including fpv139 and fpv140). Hence, the fowl poxvirus, turkey poxvirus and pigeon poxvirus strains clustered into distinct host-specific subclades A1a, A1.b and A2, respectively, which could not be seen in the FWPV-P4b and DNA polymerase phylogeny.

Isolation and molecular detection of Fowl pox and Pigeon pox viruses for the development of live attenuated vaccine seeds from the local isolates

Avipox is a viral disease of fowl and pigeon which is characterized by proliferative and nodular lesions in the feather-free parts of the skin or fibro-necrotic and proliferating part in the mouth, esophagus, and mucous membrane of the upper respiratory tract. This investigation was carried out with an aim to isolate and molecular detection of Fowl pox virus (FPV) and Pigeon pox virus (PPV) for development of live attenuated vaccine seeds from the local virus isolates. In this study, nodular lesions were collected from seven pigeons and four chickens from different areas of Mymensingh in Bangladesh which were affected by pox. Viral inoculums were prepared and DNA materials were extracted for PCR-based identification of P4b genes. Detection of virus was confirmed by PCR following propagation into 9-11 days old embryonated chicken egg (ECE) and also chicken embryo fibroblast (CEF) cell culture All the field samples were found positive for FPV and PPV by PCRR. These field isolates were propagated and attenuated in duck embryo through CAM route and duck embryo fibroblast (DEF) cell culture for the development of live attenuated vaccine seeds. Attenuation of both FPV and PPV were successful in duck embryo through CAM route and duck embryo fibroblast (DEF) cell culture after serial six passages. Attenuation of the virus was confirmed by inoculation into experimental birds. Inoculation of attenuated FPV and PPV in chicken and pigeon respectively exhibited no pox lesions whereas control chicken and pigeon inoculated with field isolates develop nodular lesions. Both FPV and PPV were confirmed from both groups of birds by PCR. These attenuated local isolates of FPV and PPV could be used as potential vaccine candidates for the prevention and control of fowl pox and pigeon pox in Bangladesh.
 J. Bangladesh Agril. Univ. 17(2): 211–219, June 2019

Economic viability of newly introduced chicken strains at village level in Tanzania: FARMSIM model simulation approach

AbstractA local chicken farming is an integral part of Tanzania's rural economy. However, despite its contributions to household economy and food security, local chicken productivity remains low because of low genetic potential, diseases and poor feeding. One of the options to increase local chicken productivity is the adoption of the chicken strains with high genetic potential. With that respect, Africa Genetic Gain project introduced Sasso and Kuroiler chicken strains for on-farm test purposes. Developmental design involved provision of 25 six weeks old chicks to 20 farmers in 12 sites making a total of 240 farmers in three regions. The study was carried out in Dodoma, Morogoro and Njombe regions to assess the effects of agro-ecological differences in the performance of these strains. The chicks were vaccinated against Mareks and Newcastle diseases at the hatchery; then against Infectious Bronchitis (IB) at 0, 7 10, 16 and 21 days. The Newcastle Disease vaccine was repeated after 10 and 21 days using LaSota vaccine. After 6 weeks, the chicks were again vaccinated against fowl pox ready for supply to farmers. A farm Simulation Model (FARMSIM) and Stochastic Efficiency with Respect to Function (SERF) were applied to access economic viability of these strains relative to local chickens. FARMSIM is a Monte Carlo Simulation Model that simultaneously evaluates a baseline and an alternative farming technology. To simulate using FARMSIM, Simulation and Econometrics to Analyse Risk (Simetar©), an excel add-in is needed as a simulating engine. Data were obtained through survey, farmers' records and simulation exercises. The results indicate that keeping Sasso strain was the most economically viable with the highest Net Present Value, Net Cash Farm Income and the highest probability of attaining economic return. Kuroiler was the second, followed by keeping local chickens without supplement and local chicken with supplement was the least economically viable enterprise. However, inclusion of risk behaviour revealed that extremely risk-averse farmers preferred mostly keeping local chickens without supplement whereas extremely risk loving farmers preferred the most Sasso strain. It is recommended that the introduced chicken strains should be promoted to increase household income and improve people's livelihoods. However, scaling up of the introduced chicken strains must be integrated with education on technical know-how for good farming practices, feed formulations, medication and shelter for improved productivity and reduced variability.

Phase I trial of a modified vaccinia ankara (MVA) priming vaccine followed by a fowlpox virus (FPV) boosting vaccine modified to express brachyury and costimulatory molecules in advanced solid tumors.

2640 Background: Brachyury, a transcription factor, plays an integral role in epithelial-to-mesenchymal transition, metastasis, poor prognosis, and resistance to chemotherapy. It is expressed in many tumor types, and rare in normal tissue, making it an ideal immunologic target. BN-Brachyury comprises heterologous vaccination with recombinant MVA priming followed by FPV boosting, each encoding transgenes for brachyury and three costimulatory molecules (B7-1, ICAM1, and LFA-3). Heterologous prime boost approach is intended to optimize immunogenicity, as previously observed. Methods: Pts with metastatic solid tumors were treated with 2 monthly doses of MVA-brachyury SC at the previously tested dose, 2.2 x 109 infectious units (IU), followed by FPV-brachyury SC, 1 x 109 IU, for 6 monthly doses and then every 3 months for up to 2 years. The primary objective was to determine safety and tolerability and establish the RP2D. Immune assays were conducted to evaluate immunogenicity. Results: In 10 pts (3 chordoma, 6 GI, 1 papillary thyroid), no dose-limiting toxicities or serious treatment-related adverse events (TRAEs) were observed. The only Grade 3 TRAE was sedation associated with fever, which resolved spontaneously and did not recur with subsequent cycles. All other TRAEs were Grade 1 or 2; the most common was injection-site reaction in all patients. Five pts have had stable disease for > 24 wks (per RECIST v1.1) and remain on treatment. One pt with chordoma, for which BN-Brachyury was granted orphan drug designation, has had a 13.2% reduction in tumor size. As previously demonstrated, brachyury-specific T cell responses were observed, as were responses against cascade antigens (non-encoded antigens) CEA and MUC-1. Conclusions: Heterologous MVA- and FPV-brachyury is well tolerated and induced immune responses to brachyury and cascade antigens, suggesting induction of immunologically relevant tumor cell destruction. These data have informed combining BN-Brachyury with checkpoint inhibition (NCT03493945) and radiation (NCT03595228) to evaluate potential for synergetic activity in selected populations. Clinical trial information: NCT03349983.

Molecular detection of integrated reticuloendothelial virus genes in fowlpox virus field isolates and live vaccines of poultry

Two field isolates (FWPV-W1 and FWPV-W2) obtained from unvaccinated backyard poultry chickens and four commercial live vaccines (FWPV-G, FWPV-V, FWPV-B and FWPV-H) of fowlpox virus origin were isolated on chorio-allantoic membrane (CAM) of embryonated chicken eggs. The CAM tissues infected with FWPV-W1, FWPVW2, FWPV-G, FWPV-V, FWPV-B and FWPV-H individually were subjected to DNA isolation. The isolated DNA was tested for the presence of P4b gene by PCR to confirm FWPV. Then, each of the field isolates and commercial vaccines were screened for presence of reticuloendothelial virus envelope (REV-env) gene and long terminal repeat (LTR) region by PCR. FWPV-W1 isolate was positive for REV-env gene (807 bp) and REV-LTR region (370 bp), which confirmed presence of near full-length REV integration in its genome. Whereas, FWPV-W2 isolate was positive for LTR region and negative for REV-env gene. This suggested that full-length REV is not present in all FWPV field isolates. All the four commercial live vaccines, were negative for REV-env gene. This showed that full-length REV is absent in these commercial vaccines, ensuring safety of the usage of these vaccines in India. However, the commercial vaccines were positive for REV-LTR region, which does not affect the vaccine safety.

Mucosal and systemic SIV-specific cytotoxic CD4+ T cell hierarchy in protection following intranasal/intramuscular recombinant pox-viral vaccination of pigtail macaques

A HIV vaccine that provides mucosal immunity is urgently needed. We evaluated an intranasal recombinant Fowlpox virus (rFPV) priming vaccine followed by intramuscular Modified Vaccinia Ankara (rMVA) booster vaccine, both expressing SIV antigens. The vaccination generated mucosal and systemic SIV-specific CD4+ T cell mediated immunity and was associated with partial protection against high-dose intrarectal SIVmac251 challenge in outbred pigtail macaques. Three of 12 vaccinees were completely protected and these animals elicited sustained Gag-specific poly-functional, cytotoxic mucosal CD4+ T cells, complemented by systemic poly-functional CD4+ and CD8+ T cell immunity. Humoral immune responses, albeit absent in completely protected macaques, were associated with partial control of viremia in animals with relatively weaker mucosal/systemic T cell responses. Co-expression of an IL-4R antagonist by the rFPV vaccine further enhanced the breadth and cytotoxicity/poly-functionality of mucosal vaccine-specific CD4+ T cells. Moreover, a single FPV-gag/pol/env prime was able to induce rapid anamnestic gp140 antibody response upon SIV encounter. Collectively, our data indicated that nasal vaccination was effective at inducing robust cervico-vaginal and rectal immunity, although cytotoxic CD4+ T cell mediated mucosal and systemic immunity correlated strongly with ‘complete protection’, the different degrees of protection observed was multi-factorial.

Molecular and histopathological diagnosis of Fowlpox virus in Chickens in Nigeria

Fowlpox is a relatively slow developing disease characterized by discrete, proliferative lesions on the skin of toes, legs or head, and/or mucous membranes of the mouth and upper respiratory tract of birds. Several diseases of birds such as infectious coryza, infectious laryngotracheitis, Mareks, and vitamin A deficiency can be confused with fowlpox, therefore there is need for an accurate and reliable method of diagnosis. Polymerase Chain Reaction (PCR) and histopathology can be used to arrive at the confirmatory diagnosis of the disease. Consequently, fifty samples from suspected cases of fowlpox from backyard poultry in Ibadan, Nigeria were collected, and PCR was used to detect and characterize the open reading frame 168 (39 kDa core protein) gene of the virus. Also, lesions from the eyelids excised were and histopathology was carried out. Thirty‐one out of 50 samples (62%) tested positive for FPV. Histopathology revealed the presence of dermal hyperplasia and Bollinger bodies which are confirmatory of fowlpox. PCR amplification of 39 kDa core protein gene and histopathology provide a reliable diagnosis of fowlpox.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Characterization of Fowlpox virus in chickens and bird-biting mosquitoes: a molecular approach to investigating Avipoxvirus transmission.

Avian pox is a highly contagious avian disease, yet relatively little is known about the epidemiology and transmission of Avipoxviruses. Using a molecular approach, we report evidence for a potential link between birds and field-caught mosquitoes in the transmission of Fowlpox virus (FWPV) in Singapore. Comparison of fpv167 (P4b), fpv126 (VLTF-1), fpv175-176 (A11R-A12L) and fpv140 (H3L) gene sequences revealed close relatedness between FWPV strains obtained from cutaneous lesions of a chicken and four pools of Culex pseudovishnui, Culex spp. (vishnui group) and Coquellitidea crassipes caught in the vicinity of the study site. Chicken-derived viruses characterized during two separate infections two years later were also identical to those detected in the first event, suggesting repeated transmission of closely related FWPV strains in the locality. Since the study location is home to resident and migratory birds, we postulated that wild birds could be the source of FWPV and that bird-biting mosquitoes could act as bridging mechanical vectors. Therefore, we determined whether the FWPV-positive mosquito pools (n=4) were positive for avian DNA using a polymerase chain reaction-sequencing assay. Our findings confirmed the presence of avian host DNA in all mosquito pools, suggesting a role for Cx. pseudovishnui, Culex spp. (vishnui group) and Cq. crassipes mosquitoes in FWPV transmission. Our study exemplifies the utilization of molecular tools to understand transmission networks of pathogens affecting avian populations, which has important implications for the design of effective control measures to minimize disease burden and economic loss.

Conventional and Molecular Detection of Avipoxviruses from Chickens, Pigeons and Turkeys

In the present study, a total of 90 cutaneous lesions samples were collected from chickens, pigeons, and turkeys farms in Dakahlia Governorate, Egypt during summer 2016. These farms suspected to be infected with Avipoxviruses (APVs).Thirty pooled samples were created (10 from chickens, 10 from pigeons and 10 from turkeys). Hyperimmune serum was prepared against standard fowlpox virus in adult white New Zealand rabbits. APV were identified in the collected samples using agar gel precipitation test (AGPT), indirect immunoperoxidase, and polymerase chain reaction (PCR) based on 4b gene of APVs. The results revealed that out of 30 tested samples there were 16 samples (53.3%) tested positive via AGPT including, 6 chicken samples (60%) , 5 pigeon samples (50%) and 5 turkey samples (50%). while using indirect immunoperoxidase, positive results were detected in 23 samples (76.7%) including, 8 chicken samples (80%), 8 pigeon samples (80%) and 7 turkey samples (70%).The 4b gene of APVs was detected using PCR in all tested samples (100%). In conclusion, Indirect immunoperoxidase is superior over AGPT in APVs detection in collected samples from chickens, pigeons and turkeys. PCR could be efficiently used in molecular diagnosis of the virus.

Conventional and Molecular Detection of Avipoxviruses from Chickens, Pigeons and Turkeys

In the present study, a total of 90 cutaneous lesions samples were collected from chickens, pigeons, and turkeys farms in Dakahlia Governorate, Egypt during summer 2016. These farms suspected to be infected with Avipoxviruses (APVs).Thirty pooled samples were created (10 from chickens, 10 from pigeons and 10 from turkeys). Hyperimmune serum was prepared against standard fowlpox virus in adult white New Zealand rabbits. APV were identified in the collected samples using agar gel precipitation test (AGPT), indirect immunoperoxidase, and polymerase chain reaction (PCR) based on 4b gene of APVs. The results revealed that out of 30 tested samples there were 16 samples (53.3%) tested positive via AGPT including, 6 chicken samples (60%) , 5 pigeon samples (50%) and 5 turkey samples (50%). while using indirect immunoperoxidase, positive results were detected in 23 samples (76.7%) including, 8 chicken samples (80%), 8 pigeon samples (80%) and 7 turkey samples (70%).The 4b gene of APVs was detected using PCR in all tested samples (100%). In conclusion, Indirect immunoperoxidase is superior over AGPT in APVs detection in collected samples from chickens, pigeons and turkeys. PCR could efficiently used in molecular diagnosis of the virus.

Chicken Embryonic-Stem Cells Are Permissive to Poxvirus Recombinant Vaccine Vectors.

The discovery of mammalian pluripotent embryonic stem cells (ESC) has revolutionised cell research and regenerative medicine. More recently discovered chicken ESC (cESC), though less intensively studied, are increasingly popular as vaccine substrates due to a dearth of avian cell lines. Information on the comparative performance of cESC with common vaccine viruses is limited. Using RNA-sequencing, we compared cESC transcriptional programmes elicited by stimulation with chicken type I interferon or infection with vaccine viruses routinely propagated in primary chicken embryo fibroblasts (CEF). We used poxviruses (fowlpox virus (FWPV) FP9, canarypox virus (CNPV), and modified vaccinia virus Ankara (MVA)) and a birnavirus (infectious bursal disease virus (IBDV) PBG98). Interferon-stimulated genes (ISGs) were induced in cESC to levels comparable to those in CEF and immortalised chicken fibroblast DF-1 cells. cESC are permissive (with distinct host transcriptional responses) to MVA, FP9, and CNPV but, surprisingly, not to PBG98. MVA, CNPV, and FP9 suppressed innate immune responses, while PBG98 induced a subset of ISGs. Dysregulation of signalling pathways (i.e., NFκB, TRAF) was observed, which might affect immune responses and viral replication. In conclusion, we show that cESC are an attractive alternative substrate to study and propagate poxvirus recombinant vaccine vectors.

Efficacy of novel recombinant fowlpox vaccine against recent Mexican H7N3 highly pathogenic avian influenza virus

Since 2012, H7N3 highly pathogenic avian influenza (HPAI) has produced negative economic and animal welfare impacts on poultry in central Mexico. In the present study, chickens were vaccinated with two different recombinant fowlpox virus vaccines (rFPV-H7/3002 with 2015 H7 hemagglutinin [HA] gene insert, and rFPV-H7/2155 with 2002 H7 HA gene insert), and were then challenged three weeks later with H7N3 HPAI virus (A/chicken/Jalisco/CPA-37905/2015). The rFPV-H7/3002 vaccine conferred 100% protection against mortality and morbidity, and significantly reduced virus shed titers from the respiratory and gastrointestinal tracts. In contrast, 100% of sham and rFPV-H7/2155 vaccinated birds shed virus at higher titers and died within 4 days. Pre- (15/20) and post- (20/20) challenge serum of birds vaccinated with rFPV-H7/3002 had antibodies detectable by hemagglutination inhibition (HI) assay using challenge virus antigen. However, only a few birds (3/20) in the rFPV-H7/2155 vaccinated group had antibodies that reacted against the challenge strain but all birds had antibodies that reacted against the homologous vaccine antigen (A/turkey/Virginia/SEP-66/2002) (20/20). One possible explanation for differences in vaccines efficacy is the antigenic drift between circulating viruses and vaccines. Molecular analysis demonstrated that the Mexican H7N3 strains have continued to rapidly evolve since 2012. In addition, we identified in silico three potential new N-glycosylation sites on the globular head of the H7 HA of A/chicken/Jalisco/CPA-37905/2015 challenge virus, which were absent in 2012 H7N3 outbreak virus. Our results suggested that mutations in the HA antigenic sites including increased glycosylation sites, accumulated in the new circulating Mexican H7 HPAIV strains, altered the recognition of neutralizing antibodies from the older vaccine strain rFPV-H7/2155. Therefore, the protective efficacy of novel rFPV-H7/3002 against recent outbreak Mexican H7N3 HPAIV confirms the importance of frequent updating of vaccines seed strains for long-term effective control of H7 HPAI virus.

WITHDRAWN: Developing of recombinant bivalent DNA vaccine deliveried by fowlpox virus vector and detecting of immunological activities to foot-and-mouth disease virus (FMDV) in animals

WITHDRAWN: Developing of recombinant bivalent DNA vaccine deliveried by fowlpox virus vector and detecting of immunological activities to foot-and-mouth disease virus (FMDV) in animals

Inoculation of fowlpox viruses coexpressing avian influenza H5 and chicken IL-15 cytokine gene stimulates diverse host immune responses

Fowlpox virus (FWPV) has been used as a recombinant vaccine vector to express antigens from several important avian pathogens. Attempts have been made to improve vaccine strains induced-host immune responses by coexpressing cytokines. This study describes the construction of recombinant FWPV (rFWPV) strain FP9 and immunological responses in specific-pathogen-free (SPF) chickens, co-expressing avian influenza virus (AIV) H5 of A/Chicken/Malaysia/5858/2004, and chicken IL-15 cytokine genes. Expression of H5 (50 kD) was confirmed by western blotting. Anti-H5 antibodies, which were measured by the haemagglutinin inhibition test, were at the highest levels at Week 3 post-inoculation in both rFWPV/H5- and rFWPV/H5/IL-15-vaccinated chickens, but decreased to undetectable levels from Week 5 onwards. CD3+/CD4+ or CD3+/CD8+T cell populations, assessed using flow cytometry, were significantly increased in both WT FP9- and rFWPV/H5-vaccinated chickens and were also higher than in rFWPV/H5/IL-15- vaccinated chickens, at Week 2. Gene expression analysis using real time quantitative polymerase chain reaction (qPCR) demonstrated upregulation of IL-15 expression in all vaccinated groups with rFWPV/H5/IL-15 having the highest fold change, at day 2 (117±51.53). Despite showing upregulation, fold change values of the IL-18 expression were below 1.00 for all vaccinated groups at day 2, 4 and 6. This study shows successful construction of rFWPV/H5 co-expressing IL-15, with modified immunogenicity upon inoculation into SPF chickens.

Viral vector and route of administration determine the ILC and DC profiles responsible for downstream vaccine-specific immune outcomes

This study demonstrates that route and viral vector can significantly influence the innate lymphoid cells (ILC) and dendritic cells (DC) recruited to the vaccination site, 24 h post delivery. Intranasal (i.n.) vaccination induced ST2/IL-33R+ ILC2, whilst intramuscular (i.m.) induced IL-25R+ and TSLPR+ (Thymic stromal lymphopoietin protein receptor) ILC2 subsets. However, in muscle a novel ILC subset devoid of the known ILC2 markers (IL-25R− IL-33R− TSLPR−) were found to express IL-13, unlike in lung. Different viral vectors also influenced the ILC-derived cytokines and the DC profiles at the respective vaccination sites. Both i.n. and i.m. recombinant fowlpox virus (rFPV) priming, which has been associated with induction of high avidity T cells and effective antibody differentiation exhibited low ILC2-derived IL-13, high NKp46+ ILC1/ILC3 derived IFN-γ and low IL-17A, together with enhanced CD11b+ CD103− conventional DCs (cDC). In contrast, recombinant Modified Vaccinia Ankara (rMVA) and Influenza A vector priming, which has been linked to low avidity T cells, induced opposing ILC derived-cytokine profiles and enhanced cross-presenting DCs. These observations suggested that the former ILC/DC profiles could be a predictor of a balanced cellular and humoral immune outcome. In addition, following i.n. delivery Rhinovirus (RV) and Adenovius type 5 (Ad5) vectors that induced elevated ILC2-derived IL-13, NKp46+ ILC1/ILC3-derived-IFN-γ and no IL-17A, predominantly recruited CD11b− B220+ plasmacytoid DCs (pDC). Knowing that pDC are involved in antibody differentiation, we postulate that i.n. priming with these vectors may favour induction of effective humoral immunity. Our data also revealed that vector-specific replication status and/or presence or absence of immune evasive genes can significantly alter the ILC and DC activity. Collectively, our findings suggest that understanding the route- and vector-specific ILC and DC profiles at the vaccination site may help tailor/design more efficacious viral vector-based vaccines, according to the pathogen of interest.

Long-term protection against a virulent field isolate of infectious laryngotracheitis virus induced by inactivated, recombinant, and modified live virus vaccines in commercial layers

ABSTRACTInfectious laryngotracheitis (ILT) is an acute respiratory disease of chickens controlled through vaccination with live-modified attenuated vaccines, the chicken embryo origin (CEO) vaccines and the tissue-culture origin (TCO) vaccines. Recently, novel recombinant vaccines have been developed using herpesvirus of turkey (HVT) and fowl pox virus (FPV) as vectors to express ILTV immunogens for protection against ILT. The objective of this study was to assess the protection efficacy against ILT induced by recombinants, live-modified attenuated, and inactivated virus vaccines when administered alone or in combination. Commercial layer pullets were vaccinated with one or more vaccines and challenged at 35 (35 WCH) or 74 weeks of age (74 WCH). Protection was assessed by scoring clinical signs; and by determining the challenge viral load in the trachea at five days post-challenge. The FPV-LT vaccinated birds were not protected when challenged at 35 weeks; the HVT-LT and TCO vaccines in combination provided protection similar to that observed in chickens vaccinated with either HVT-LT or TCO vaccines when challenged at 35 weeks, whereas protection induced by vaccination with HVT-LT followed by TCO was superior in the 74 WCH group compared with the 35 WCH group. Birds given the inactivated ILT vaccine had fewer clinical signs and/or lower viral replication at 74 WCH when combined with TCO or HVT-LT, but not when given alone. Finally, the CEO-vaccinated birds had top protection as indicated by reduction of clinical signs and viral replication when challenged at 35 weeks (74 weeks not done). These results suggest that certain vaccine combinations may be successful to produce long-term protection up to 74 weeks of age against ILT.