Fowlpox Research Articles

TURKEY CORONAVIRUS: AN UPDATED REVIEW

Turkey coronavirus (TCoV) causes acute atrophic enteritis and uneven flock growth in turkey farms leading to economic loss. Since 1990's, turkey flocks have kept experiencing coronaviral enteritis sporadically in the United States, Canada, Europe, and Brazil. Poult enteritis and mortality syndrome (PEMS) caused by the co-infection of TCoV, astrovirus, and other viruses or bacteria resulted in significantly high mortality. Diagnosis of TCoV depends on reverse transcription polymerase chain reaction (RT-PCR), quantitative real-time PCR, immunohistochemistry (IHC), immunofluorescent antibody assay and virus isolation (VI). Genomic organization of TCoV is as follows: 5′ UTR-1a-1b-S-3a-3b-E-M-5a-5b-N-UTR 3′. Genomic analysis suggests the emergence of TCoV from infectious bronchitis virus (IBV) through the recombination of spike (S) gene. Both TCoV and IBV belong to species Avian coronavirus in genus Gammacoronavirus and have a single stranded RNA genome with a size about 27 kb. High similarity of S genes has been found between TCoV isolates in contrast to low similarity between IBV strains. TCoV infection induced strong humoral and cellular immune responses, characterized by high levels of antibody and interferon gamma. The fragment containing neutralizing epitopes in the S protein has been identified. Vaccines conferring protection against TCoV have not been developed and used in the fields but live attenuated, killed, DNA, and fowlpox virus vectored vaccines have been generated and their efficacies were evaluated. Molecular epidemiology of TCoV in recent outbreaks sheds more information on the evolution and transmission of TCoV, which will aid in developing effective vaccines or treatment to prevent, control, or eliminate TCoV infection.

The L1 protein of human papilloma virus 16 expressed by a fowlpox virus recombinant can assemble into virus-like particles in mammalian cell lines but elicits a non-neutralising humoral response

Human papilloma virus (HPV)-16 is the prevalent genotype associated with cervical tumours. Virus-like-particle (VLP)-based vaccines have proven to be effective in limiting new infections of high-risk HPVs, but their high cost has hampered their use, especially in the poor developing countries. Avipox-based recombinants are replication-restricted to avian species and represent efficient and safe vectors also for immunocompromised hosts, as they can elicit a complete immune response. A new fowlpox virus recombinant encoding HPV-L1 (FPL1) was engineered and evaluated side-by-side with a FP recombinant co-expressing L1 and green fluorescent protein (FPL1GFP) for correct expression of L1 in vitro in different cell lines, as confirmed by Western blotting, immunofluorescence, real-time PCR, and electron microscopy. Mice were also immunised to determine its immunogenicity. Here, we demonstrate that the FPL1 recombinant better expresses L1 in the absence of GFP, correctly assembles structured capsomers into VLPs, and elicits an immune response in a preclinical animal model. To our knowledge, this is the first report of HPV VLPs assembled in eukaryotic cells using an avipox recombinant.

Antibody titer has positive predictive value for vaccine protection against challenge with natural antigenic-drift variants of H5N1 high-pathogenicity avian influenza viruses from Indonesia.

Vaccines are used in integrated control strategies to protect poultry against H5N1 high-pathogenicity avian influenza (HPAI). H5N1 HPAI was first reported in Indonesia in 2003, and vaccination was initiated in 2004, but reports of vaccine failures began to emerge in mid-2005. This study investigated the role of Indonesian licensed vaccines, specific vaccine seed strains, and emerging variant field viruses as causes of vaccine failures. Eleven of 14 licensed vaccines contained the manufacturer's listed vaccine seed strains, but 3 vaccines contained a seed strain different from that listed on the label. Vaccines containing A/turkey/Wisconsin/1968 (WI/68), A/chicken/Mexico/28159-232/1994 (Mex/94), and A/turkey/England/N28/1973 seed strains had high serological potency in chickens (geometric mean hemagglutination inhibition [HI] titers, ≥ 1:169), but vaccines containing strain A/chicken/Guangdong/1/1996 generated by reverse genetics (rg; rgGD/96), A/chicken/Legok/2003 (Legok/03), A/chicken/Vietnam/C57/2004 generated by rg (rgVN/04), or A/chicken/Legok/2003 generated by rg (rgLegok/03) had lower serological potency (geometric mean HI titers, ≤ 1:95). In challenge studies, chickens immunized with any of the H5 avian influenza vaccines were protected against A/chicken/West Java/SMI-HAMD/2006 (SMI-HAMD/06) and were partially protected against A/chicken/Papua/TA5/2006 (Papua/06) but were not protected against A/chicken/West Java/PWT-WIJ/2006 (PWT/06). Experimental inactivated vaccines made with PWT/06 HPAI virus or rg-generated PWT/06 low-pathogenicity avian influenza (LPAI) virus seed strains protected chickens from lethal challenge, as did a combination of a commercially available live fowl poxvirus vaccine expressing the H5 influenza virus gene and inactivated Legok/03 vaccine. These studies indicate that antigenic variants did emerge in Indonesia following widespread H5 avian influenza vaccine usage, and efficacious inactivated vaccines can be developed using antigenic variant wild-type viruses or rg-generated LPAI virus seed strains containing the hemagglutinin and neuraminidase genes of wild-type viruses. H5N1 high-pathogenicity avian influenza (HPAI) virus has become endemic in Indonesian poultry, and such poultry are the source of virus for birds and mammals, including humans. Vaccination has become a part of the poultry control strategy, but vaccine failures have occurred in the field. This study identified possible causes of vaccine failure, which included the use of an unlicensed virus seed strain and induction of low levels of protective antibody because of an insufficient quantity of vaccine antigen. However, the most important cause of vaccine failure was the appearance of drift variant field viruses that partially or completely overcame commercial vaccine-induced immunity. Furthermore, experimental vaccines using inactivated wild-type virus or reverse genetics-generated vaccines containing the hemagglutinin and neuraminidase genes of wild-type drift variant field viruses were protective. These studies indicate the need for surveillance to identify drift variant viruses in the field and update licensed vaccines when such variants appear.

Detection and Genetic Characterization of an Avipox Virus Isolate from Domestic Pigeon (Columba livia domestica) in Morogoro Region, Eastern Tanzania

Aim: To determine molecular and evolutionary characteristics of a newly isolated Tanzanian isolate of pigeonpox virus (PGPV). Study Design: Experimental. Place and Duration of Study: Faculty of Veterinary Medicine, Sokoine University of Agriculture, Morogoro, Tanzania; between November 2011 and May 2014. Methodology: Samples of cutaneous nodular lesions were collected from 17 pigeons suspected to have pigeonpox in Morogoro (n = 11), Pwani (n = 2) and Dar es Salaam (n = 4) regions; followed Original Research Article Masola et al.; AIR, 3(5): 460-469, 2015; Article no.AIR.2015.041 461 by virus isolation, and confirmation by amplification and sequencing of P4b gene. Further the sequence was phylogenetically analyzed for its evolutionary relationship with other related viruses. Results: PGPV was detected in two samples, both from Morogoro region. Sequence analysis revealed that the Tanzanian PGPV isolate derived in this study was 90 – 99% identical to several avipoxvirus isolates from birds belonging to different species from several countries; for instance the Tanzanian PGPV isolate was 91% identical to each of the Tanzanian fowlpox virus isolates derived in the previous study, and 99% identical to all three PGPV isolates whose sequences were obtained in the GenBank i.e PGPV isolates from India (accession number DQ873811), Egypt (accession number JQ665840) and a PGPV (accession number AY530303) whose country of origin is unknown. Phylogenetic analysis revealed that the Tanzanian PGPV isolate belongs to clade A in subclade A2, sharing a recent common ancestor with members of subclade A3. Conclusion: Currently, pigeonpox virus is circulating in Morogoro region. The present study warrants the further surveillance/ molecular epidemiology of PGPV in Tanzania in a large-scale.

Construction of FWPV Chimaeric MVA.

Construction of chimaeric MVA is a useful tool with which to study gene function of related viruses. The protocol given here describes MVA chimaeras containing genes from Fowlpox virus (FWPV), although this can be applied to DNA derived from other organisms. There are a number of steps required to make the chimaeric MVA: 1) Purification of viral particles; 2) Extraction of DNA from purified viral particles; 3) Assembly of linear recombination templates; 4) Transfection of linear recombination templates; 5) Selection of chimaeric MVA. Note: This procedure uses live virus, and should be conducted using Good Microbiological Practice, in accordance with international and national biocontainment requirements. This procedure also involves Genetic Modification of microorganisms, and appropriate safety approval should be obtained before commencing.

Transient dominant selection for the modification and generation of recombinant infectious bronchitis coronaviruses.

We have developed a reverse genetics system for the avian coronavirus infectious bronchitis virus (IBV) in which a full-length cDNA corresponding to the IBV genome is inserted into the vaccinia virus genome under the control of a T7 promoter sequence. Vaccinia virus as a vector for the full-length IBV cDNA has the advantage that modifications can be introduced into the IBV cDNA using homologous recombination, a method frequently used to insert and delete sequences from the vaccinia virus genome. Here, we describe the use of transient dominant selection as a method for introducing modifications into the IBV cDNA; this has been successfully used for the substitution of specific nucleotides, deletion of genomic regions, and the exchange of complete genes. Infectious recombinant IBVs are generated in situ following the transfection of vaccinia virus DNA, containing the modified IBV cDNA, into cells infected with a recombinant fowlpox virus expressing T7 DNA-dependent RNA polymerase.

Trials for increasing the infectivity titer of fowl pox vaccines prepared on SPF embroynated chicken egg and tissue culture

The present work was designed to study the effect of DEAE-dextran and Magnesium Chloride (MgCl) on fowl pox virus vaccine (FPV) in order to obtain a maximum titer allowing the massive production of the vaccine. Fowl pox virus; used for vaccine production; was propagated on embroynated chicken eggs (ECE) and chicken embryo fibroblast (CEF), the virus was inoculated in ECE and CEF without DEAE-dextran nor MgCl, and with DEAE-Dextran and MgCl separately. The time of harvestion was early as one day post inoculation in CEF. The virus titer were higher in case of treated inoculums with DEAE-dextran and MgCl reaching (6.2 and 7.5 log10TCID50/ml respectively) on CEF and (6.2 and 6.7 Log10EID50 respectively) on ECE. Fowl pox vaccines (FPV) were prepared before and after DEAE-Dextran and MgCl treatment. The application of quality control assays revealed the safety, sterility and potency of the prepared vaccines. Immune response of the prepared FPV vaccines were evaluated in chickens using virus neutrization test (VNT). It was found that, the use of DEAE-Dextran and MgCl with the recommended concentrations could result in increasing the virus titer with reduction in the time of harvestation and accordingly increase the vaccine production and decrease its cost.

Construction and characterization of novel fowlpox virus shuttle vectors

Viral vectors are important vehicles in vaccine research. Avipoxviruses including fowlpox virus (FPV) play major roles in viral vaccine vector development for the prevention and therapy of human and other veterinary diseases due to their immunomodulatory effects and safety profile. Recently, we analyzed the genomic and proteomic backgrounds of the Chinese FPV282E4 strain. Based on analysis of the whole genome of FPV282E4, the FPV150 and FPV193 loci were chosen as insertion sites for foreign genes, and two shuttle vectors with a triple-gene expression cassette were designed and constructed. Homologous recombination between the FPV virus genome and sequences within the shuttle plasmids in infected cells was confirmed. The recombinants were obtained through several rounds of plaque purification using enhanced green fluorescent protein as a reporter and evaluated for the correct expression of foreign genes in vitro using RT-PCR, real-time PCR and Western blotting. Morphogenesis and growth kinetics were assayed via transmission electron microscopy and viral titering, respectively. Results showed that recombinant viruses were generated and correctly expressed foreign genes in CEF, BHK-21 and 293T cells. At least three different exogenous genes could be expressed simultaneously and stably over multiple passages. Additionally, the FPV150 mutation, FPV193 deletion and insertion of foreign genes did not affect the morphogenesis, replication and proliferation of recombinant viruses in cells. Our study contributes to the improvement of FPV vectors for multivalent vaccines.

Differential diagnosis of fowlpox and infectious laryngotracheitis viruses in chicken diphtheritic manifestations by mono and duplex real-time polymerase chain reaction

Infectious laryngotracheitis virus (ILTV) and fowlpox virus (FPV) cause diphtheritic lesions in chicken tracheas and can simultaneously infect the same bird. A differential molecular diagnostic test, the duplex real-time polymerase chain reaction, is now reported using ILTV and FPV vaccine viruses and clinical samples from chickens, either uninfected or naturally infected with ILTV or FPV, or with both viruses. The dual virus amplification by real-time polymerase chain reaction was demonstrated to behave similarly to monoplex amplification, in spite of the fact that the real-time exponential amplification plots of the vaccine viruses were more illustrative than those of the clinical samples.

Immunogenicity and efficacy of fowlpox-vectored and inactivated avian influenza vaccines alone or in a prime-boost schedule in chickens with maternal antibodies

Inactivated and fowlpox virus (FP)-vectored vaccines have been used to control H5 avian influenza (AI) in poultry. In H5 AI endemic countries, breeder flocks are vaccinated and therefore, maternally-derived antibodies (MDA) are transferred to their progeny. Results of three immunogenicity and one efficacy studies performed in birds with or without MDA indicated that the immunogenicity of an inactivated vaccine based on a H5N9 AI isolate (inH5N9) was severely impaired in chicks hatched from inH5N9-vaccinated breeders. This MDA interference was lower when breeders received only one administration of the same vaccine and could be overcome by priming the chicks at day-of-age with a live recombinant FP-vectored vaccine with H5 avian influenza gene insert (FP-AI). The interference of anti-FP MDA was of lower intensity than the interference of anti-AI MDA. The highest interference observed on the prime-boost immunogenicity was in chicks hatched from breeders vaccinated with the same prime-boost scheme. The level of protection against an antigenic variant H5N1 highly pathogenic AI isolate from Indonesia against which the FP-AI or inH5N9 alone was poorly protective could be circumvented by the prime-boost regimen in birds with either FP or AI MDA. Thus, the immunogenicity of vaccines in young chicks with MDA depends on the vaccination scheme and the type of vaccine used in their parent flocks. The heterologous prime-boost in birds with MDA may at least partially overcome MDA interference on inactivated vaccine.

Different HIV pox viral vector-based vaccines and adjuvants can induce unique antigen presenting cells that modulate CD8 T cell avidity

The lung-derived dendritic cell (LDC) recruitment following intranasal (i.n.) vaccination of different poxviral vector-based vaccines/adjuvants were evaluated to decipher how these factors influenced CD8+ T cell avidity. Compared to the standard i.n. recombinant fowlpox virus (FPV)-HIV vaccination, the FPV-HIV IL-13Rα2 or IL-4Rα antagonist adjuvanted vaccines that induced higher avidity CD8+ T cells, also recruited significantly elevated MHCII+ CD11c+ CD11b+ CD103− CD64− MAR-1− conventional DC (cDCs) to the lung mucosae (hierarchy: IL-4R antagonist>IL-13Rα2>unadjuvanted). In contrast, elevated CD11b− CD103+ LDCs were detected in animals that received recombinant HIV vaccinia virus (rVV) or Modified Vaccinia Ankara virus (MVA) vector-based vaccines. Adoptive transfer studies indicated that CD11b− CD103+ LDCs significantly dampened HIV-specific CD8+ T cell avidity compared to CD11b+ CD103− LDCs. Collectively; our observations revealed that rFPV vector prime and transient inhibition of IL-4/IL-13 at the vaccination site favoured the recruitment of unique LDCs, associated with the induction of high quality immunity.

Efficacy of fowl pox vaccines against Egyptian isolated strain during 2012

Aim: This study was designed to evaluate the protection induced by different commercial fowl pox (FP) vaccines against local FP virus isolated from Giza governorate in Egypt during 2012. Materials and Methods: Efficacy of FP vaccines against local field isolates was determined in seven groups of (20 birds/ group) 6 weeks old specific-pathogen free chicks. Each group was vaccinated via wing web with one of different FP living vaccines and (20) chicks in group (8) did not receive any FP vaccine and served as controls. At the 3rd, 5th, 7th and 10th-day post-vaccination (DPV), all birds were examined for the presence of takes at the site of vaccination. Three weeks post vaccination, serum samples were collected, and the levels of induced antibodies were detected by passive hemagglutination (PH) test. All birds in Groups (1-8A) were challenged individually via the wing web with EID50 103.0 of the Egyptian isolated strain during 2012. Results: Takes detected at the site of vaccination at the 3rd day were ranging from 45 to 70%. This percent increased to 80-95% at the 5th DPV with a maximum elevation of takes at the 7th DPV (90-100%). Geometric mean titer of PH assay antibody titer, 3 weeks post vaccination, was ranging between 5.60 and 9.60 according to the type of vaccine used and with protection 90-100%. Conclusion: Efficacy of some commercial FP vaccines used in the poultry field against the Egyptian isolated strain during 2012 ranged between 90% and 100% according to the type of used vaccine.

Lack of evidence that avian oncogenic viruses are infectious for humans: a review.

Chickens may be infected with three different oncogenic viruses: avian leukosis virus (ALV), reticuloendotheliosis virus (REV), and Marek's disease herpesvirus (MDV). Several epidemiological studies have suggested a link between these viruses and different types of cancer in people working in poultry processing plants and with multiple sclerosis. In this article, we analyze the epidemiological evidence that these viruses are causative agents for human cancer, followed by description of the relevant key characteristics of ALV, REV, and MDV. Finally, we discuss the biological evidence or lack thereof that avian tumor viruses are involved in the etiology of human cancer and multiple sclerosis (MS). The recent primary epidemiologic articles that we reviewed as examples were only hypothesis-generating studies examining massive numbers of risk factors for associations with various imprecise, non-viral-specific outcomes. The studies lacked precise evidence of exposure to the relevant viruses and the statistical methods failed to adjust for the large risks of false-positive claims. ALV subgroups A-D and J have been eradicated in the United States from the pure lines down to the parent stocks by the breeder companies, which have greatly reduced the incidence of infection in layer flocks and broilers. As a consequence, potential exposure of humans to these viruses has greatly diminished. Infection of humans working in processing plants with ALV-A and ALV-B is unlikely, because broilers are generally resistant to infection with these two subgroups. Moreover, these viruses enter cells by specific receptors present on chicken, but not on mammalian, cells. Infection of mammalian cell cultures or animals with ALV-A, ALV-B, and ALV-J has not been reported. Moreover, humans vaccinated with exogenous or endogenous ALV-contaminated vaccines against yellow fever, measles, and mumps did not become antibody- or virus-positive for ALV. The risks for human infection with REV are similarly limited. First of all, REV also has been eradicated from pure lines down to parent stock by breeder companies in the United States. Broilers can still become infected with REV through infection with fowl pox virus containing REV. However, there is no indication that REV can infect human cells. Low levels of antibodies to ALV and REV in human sera have been reported by a few groups. Absorption of sera with chicken antigens reduced the antibody titers, and there was no clear association with contacts with poultry. Possible cross-reactions with human endogenous or exogenous retroviruses were not considered in these publications. MDV is typically associated with infection of chickens, and almost all experimental data show that MDV cannot infect mammalian cells or animals, including nonhuman primates. One study reports the presence of MDV gD DNA in human sera, but this finding could not be confirmed by another group. A Medline search of the term "gene expression in human cancers" was negative for publications with avian retroviruses or MDV. In conclusion, there is no indication that avian oncogenic viruses are involved in human cancer or MS or even able to infect and replicate in humans.

Novel HIV IL-4R antagonist vaccine strategy can induce both high avidity CD8 T and B cell immunity with greater protective efficacy

We have established that the efficacy of a heterologous poxvirus vectored HIV vaccine, fowlpox virus (FPV)-HIV gag/pol prime followed by attenuated vaccinia virus (VV)-HIV gag/pol booster immunisation, is strongly influenced by the cytokine milieu at the priming vaccination site, with endogenous IL-13 detrimental to the quality of the HIV specific CD8+ T cell response induced. We have now developed a novel HIV vaccine that co-expresses a C-terminal deletion mutant of the mouse IL-4, deleted for the essential tyrosine (Y119) required for signalling. In our vaccine system, the mutant IL-4C118 can bind to IL-4 type I and II receptors with high affinity, and transiently prevent the signalling of both IL-4 and IL-13 at the vaccination site. When this IL-4C118 adjuvanted vaccine was used in an intranasal rFPV/intramuscular rVV prime-boost immunisation strategy, greatly enhanced mucosal/systemic HIV specific CD8+ T cells with higher functional avidity, expressing IFN-γ, TNF-α and IL-2 and greater protective efficacy were detected. Surprisingly, the IL-4C118 adjuvanted vaccines also induced robust long-lived HIV gag-specific serum antibody responses, specifically IgG1 and IgG2a. The p55-gag IgG2a responses induced were of a higher magnitude relative to the IL-13Rα2 adjuvant vaccine. More interestingly, our recently tested IL-13Rα2 adjuvanted vaccine which only inhibited IL-13 activity, even though induced excellent high avidity HIV-specific CD8+ T cells, had a detrimental impact on the induction of gag-specific IgG2a antibody immunity. Our observations suggest that (i) IL-4 cell-signalling in the absence of IL-13 retarded gag-specific antibody isotype class switching, or (ii) IL-13Rα2 signalling was involved in inducing good gag-specific B cell immunity. Thus, we believe our novel IL-4R antagonist adjuvant strategy offers great promise not only for HIV-1 vaccines, but also against a range of chronic infections where sustained high quality mucosal and systemic T and B cell immunity are required for protection.

NY-ESO-1 specific antibody and cellular responses in melanoma patients primed with NY-ESO-1 protein in ISCOMATRIX and boosted with recombinant NY-ESO-1 fowlpox virus.

Vaccination strategies based on repeated injections of NY-ESO-1 protein formulated in ISCOMATRIX particles (NY-ESO-1 ISCOMATRIX) have shown to elicit combined NY-ESO-1 specific antibody and T cell responses. However, it remains unclear whether heterologous prime-boost strategies based on the combination with NY-ESO-1 ISCOMATRIX with different NY-ESO-1 boosting reagents could be used to increase NY-ESO-1 CD8(+) or CD4(+) T cell responses. To address this question, we carried out a randomized clinical trial in 39 high-risk, resected melanoma patients vaccinated with NY-ESO-1 ISCOMATRIX, and then boosted with repeated injections of either recombinant fowlpox virus encoding full length NY-ESO-1 (rF-NY-ESO-1) (Arm A) or NY-ESO-1 ISCOMATRIX alone (Arm B). We have comprehensively analyzed NY-ESO-1 specific T cells and B cells response in all patients before and after vaccination for a total of seven time points per patient. NY-ESO-1 ISCOMATRIX alone elicited a strong NY-ESO-1 specific CD4(+) T cell and antibody response, which was maintained by both regiments at similar levels. However, CD8(+) T cell responses were significantly boosted in 3 out of 18 patients in Arm A after the first rF-NY-ESO-1 injection and such responses were maintained until the end of the trial, while no patients in Arm B showed similar CD8(+) T cell responses. In addition, our results clearly identified immunodominant regions in the NY-ESO-1 protein: NY-ESO-179-102 and NY-ESO-1115-138 for CD4+ T cells and NY-ESO-185-108 for CD8+ T cells in a large proportion of vaccinated patients. These regions of NY-ESO-1 protein should be considered in future clinical trials as immunodominant epitopes.

Relatively high prevalence of pox-like lesions in Henslow's sparrow (Ammodrammus henslowii) among nine species of migratory grassland passerines in Wisconsin, USA.

Globally, Avipoxvirus species affect over 230 species of wild birds and can significantly impair survival. During banding of nine grassland songbird species (n=346 individuals) in southwestern Wisconsin, USA, we noted species with a 2-6% prevalence of pox-like lesions (possible evidence of current infection) and 4-10% missing digits (potential evidence of past infection). These prevalences approach those recorded among island endemic birds (4-9% and 9-20% for the Galapagos and Hawaii, respectively) for which Avipoxvirus species have been implicated as contributing to dramatic population declines. Henslow's Sparrow Ammodramus henslowii (n=165 individuals) had the highest prevalence of lesions (6.1%) and missing digits (9.7%). Among a subset of 26 Henslow's Sparrows from which blood samples were obtained, none had detectable antibody reactive to fowlpox virus antigen. However, four samples (18%) had antibody to canarypox virus antigen with test sample and negative control ratios (P/N values) ranging from 2.4 to 6.5 (median 4.3). Of four antibody-positive birds, two had lesions recorded (one was also missing a digit), one had digits missing, and one had no signs. Additionally, the birds with lesions or missing digits had higher P/N values than did the antibody-positive bird without missing digits or recorded lesions. This study represents an impetus for considering the impacts and dynamics of disease caused by Avipoxvirus among North American grassland bird species.

Adjuvant-active fraction from Albizia julibrissin saponins improves immune responses by inducing cytokine and chemokine at the site of injection.

The total saponin from the stem bark of Albizia julibrissin (AJSt) has previously showed the adjuvant potentials in mice. In this study, AJSt was subjected to resin column chromatography to afford four fractions (AJS30, AJS50, AJS75 and AJS95), and these fractions were further compared for the hemolytic activities and adjuvant potentials on the immune response to ovalbumin (OVA) and recombinant fowl pox virus vector-based avian influenza vaccine (rFPV). AJSt, AJS50, AJS75 and AJS95 showed a slight hemolytic effect. AJSt, AJS50 and AJS75 significantly enhanced not only the concanavalin A (Con A)-, lipopolysaccharide (LPS)- and antigen-stimulated splenocyte proliferation, but also serum antigen-specific IgG, IgG1, IgG2a and IgG2b antibody titers in the mice immunized with OVA and rFPV. AJSt, AJS50 and AJS75 also significantly promoted the NK cell activity and delayed-type hypersensitivity (DTH) in the OVA-immunized mice. Furthermore, the mechanisms of adjuvant action were explored by determining the effects of AJS75 on cytokines and chemokines at the site of injection using antibody array. AJS75 induced or up-regulated the protein expression of 12 cytokines (IL-12p40, IL-12p40/p70, IFN-γ, IL-13, IL-1β, IL-6, IL-10, TNF-α, sTNFR I, sTNFR III, IL-3 and IL-9) and 10 chemokines (Eotaxin, I-TAC, MIG, MIP-1α, RANTES, TECK, Fracatlkine, FasL, M-CSF and GM-CSF) in the injected muscles. The results suggested that AJS75, the most adjuvant-active fraction of AJSt, could improve antigen-specific both cellular and humoral immune responses and simultaneously elicit a Th1/Th2 response by inducing cytokine and chemokine at the site of injection.

Highly pathogenic fowlpox virus in cutaneously infected chickens, China.

We investigated an acute outbreak of the cutaneous form of fowlpox among chickens in China in November 2009. Using pathologic and virologic methods, we identified a novel type of fowlpox virus that carried an integrated genomic sequence of reticuloendotheliosis virus. This highly pathogenic virus could lead to severe ecologic effects and economic losses.

Fowlpox virus encodes two p28-like ubiquitin ligases that are expressed early and late during infection

Many cellular processes are regulated by the ubiquitin–proteasome system. Therefore, it is not surprising that viruses have adapted ways to manipulate the ubiquitin–proteasome system to their own advantage. p28 is a poxvirus encoded ubiquitin ligase that contains an N-terminal KilA-N DNA binding domain and a C-terminal RING domain required for ubiquitin ligase activity. p28 is encoded by a wide range of poxviruses, including members of the Avipoxviruses. Here we show that fowlpox virus (FWPV) and canarypox virus (CNPV) each contain two distinct p28-like ubiquitin ligases; an observation not seen in other members of the poxvirus family. FWPV150 and FWPV157 are both ubiquitinated during infection and co-localize with conjugated ubiquitin at the viral factory. Interestingly, we demonstrate that FWPV150 was actively transcribed early, while FWPV157 was expressed late. Overall, these observations suggest different temporal roles for FWPV150 and FWPV157, an observation unique to the Avipoxviruses.

The complete genome sequences of poxviruses isolated from a penguin and a pigeon in South Africa and comparison to other sequenced avipoxviruses.

BackgroundTwo novel avipoxviruses from South Africa have been sequenced, one from a Feral Pigeon (Columba livia) (FeP2) and the other from an African penguin (Spheniscus demersus) (PEPV). We present a purpose-designed bioinformatics pipeline for analysis of next generation sequence data of avian poxviruses and compare the different avipoxviruses sequenced to date with specific emphasis on their evolution and gene content.ResultsThe FeP2 (282 kbp) and PEPV (306 kbp) genomes encode 271 and 284 open reading frames respectively and are more closely related to one another (94.4%) than to either fowlpox virus (FWPV) (85.3% and 84.0% respectively) or Canarypox virus (CNPV) (62.0% and 63.4% respectively). Overall, FeP2, PEPV and FWPV have syntenic gene arrangements; however, major differences exist throughout their genomes. The most striking difference between FeP2 and the FWPV-like avipoxviruses is a large deletion of ~16 kbp from the central region of the genome of FeP2 deleting a cc-chemokine-like gene, two Variola virus B22R orthologues, an N1R/p28-like gene and a V-type Ig domain family gene. FeP2 and PEPV both encode orthologues of vaccinia virus C7L and Interleukin 10. PEPV contains a 77 amino acid long orthologue of Ubiquitin sharing 97% amino acid identity to human ubiquitin.ConclusionsThe genome sequences of FeP2 and PEPV have greatly added to the limited repository of genomic information available for the Avipoxvirus genus. In the comparison of FeP2 and PEPV to existing sequences, FWPV and CNPV, we have established insights into African avipoxvirus evolution. Our data supports the independent evolution of these South African avipoxviruses from a common ancestral virus to FWPV and CNPV.