Publications by authors named "Madhan Mohan Chellappa"

20 Publications

  • Page 1 of 1

Molecular characterization of porcine circovirus 2 circulating in Assam and Arunachal Pradesh of India.

Anim Biotechnol 2021 Aug 10:1-5. Epub 2021 Aug 10.

Recombinant DNA Laboratory, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Bareilly, India.

PCV2 is the primary etiological agent of porcine circovirus-associated diseases (PCVADs) which affect pigs worldwide. Currently, there is a worldwide genotype prevalence switch from PCV2b to PCV2d, which has led to increased virulence of the circulating virus strains leading to vaccine failures and selection pressure. In the present study, the PCV2 genotypes circulating in north eastern region (NER) of India particularly the states of Assam and Arunachal Pradesh was characterized by isolation, sequencing and phylogenetic analysis of gene. The phylogenetic analysis revealed that the PCV2 isolates circulating in pigs of Assam and Arunachal Pradesh were mostly of PCV2d genotype. Hence, it can be concluded that PCV2d genotype is the most dominating genotype in NER and priority should be given to this genotype for development of future vaccine candidate against PCV2 in India.
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http://dx.doi.org/10.1080/10495398.2021.1955700DOI Listing
August 2021

Evaluation of the oncolytic property of recombinant Newcastle disease virus strain R2B in 4T1 and B16-F10 cells in-vitro.

Res Vet Sci 2021 Oct 25;139:159-165. Epub 2021 Jul 25.

Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India. Electronic address:

Recombinant Newcastle disease virus vectors have gained a lot of interest for its oncolytic virus therapy and cancer immune therapeutic properties due to its selective replication to high titers in cancer cells. The aim of this study was to find out the oncolytic effects of mesogenic recombinant NDV strain R2B-GFP on murine mammary tumor cell line 4T1 and murine melanoma cell line B16-F10. The anti-tumor effects of R2B-GFP virus were studied via expression of virus transgene GFP in cancer cells, evaluating its cytotoxicity and cell migration efficacies by MTT and wound healing assays respectively. In addition, the underlying apoptotic mechanism of R2B-GFP virus was estimated by TUNEL assay, colorimetric estimation of Caspase-3, 8 and 9 and the estimation of Bax to Bcl-2 ratio. The results showed a significant decrease in viability of both 4T1 and B16-F10 cells infected with R2B-GFP virus at 0.1 and 1 MOI. R2B-GFP virus could significantly induce apoptosis in the 4T1 and B16-F10 cells as compared to the uninfected control. Further, a flow cytometry analysis on apoptotic cells percentage and mitochondria membrane permeability test was also studied in R2B-GFP virus treated 4T1 and B16-F10 cell lines. The R2B-GFP virus caused an increase in loss of mitochondrial membrane permeability in both 4T1 and B16-F10 cells indicating the involvement of mitochondrial regulated cell death. Thus, the recombinant virus R2B-GFP virus proved to be a valid candidate for oncolytic viral therapy in 4T1 and B16-F10 cells.
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http://dx.doi.org/10.1016/j.rvsc.2021.07.028DOI Listing
October 2021

Newcastle disease virus vectored rabies vaccine induces strong humoral and cell mediated immune responses in mice.

Vet Microbiol 2020 Dec 12;251:108890. Epub 2020 Oct 12.

Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly, 243 122, India. Electronic address:

Rabies is a devastating disease affecting almost all mammalian animal species including humans. Vaccines are available to combat the disease. Protection against the disease is rendered by assessing the humoral immune response. Recent reports suggest the role of cell mediated immune response (CMI) in assessing vaccine efficacy. In the present study, two live vectored vaccine candidates containing glycoprotein G of rabies virus were generated using the mesogenic Newcastle disease virus (NDV) strain R2B and another with NDV with an altered fusion protein cleavage site as backbones. The efficacy of these vaccine candidates on testing in experimental mouse model indicated generation of robust humoral and CMI responses. The recombinant NDV containing the altered fusion protein cleavage site with glycoprotein G showed the highest CMI response in mice indicating its usage as a potential live vectored vaccine candidate against the disease.
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http://dx.doi.org/10.1016/j.vetmic.2020.108890DOI Listing
December 2020

Recombinant Newcastle Disease Virus (NDV) Expressing Sigma C Protein of Avian Reovirus (ARV) Protects against Both ARV and NDV in Chickens.

Pathogens 2019 Sep 10;8(3). Epub 2019 Sep 10.

Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India.

Newcastle disease (ND) and avian reovirus (ARV) infections are a serious threat to the poultry industry, which causes heavy economic losses. The mesogenic NDV strain R2B is commonly used as a booster vaccine in many Asian countries to control the disease. In this seminal work, a recombinant NDV strain R2B expressing the sigma C (σC) gene of ARV (rNDV-R2B-σC) was generated by reverse genetics, characterized in vitro and tested as a bivalent vaccine candidate in chickens. The recombinant rNDV-R2B-σC virus was attenuated as compared to the parent rNDV-R2B virus as revealed by standard pathogenicity assays. The generated vaccine candidate, rNDV-R2B-σC, could induce both humoral and cell mediated immune responses in birds and gave complete protection against virulent NDV and ARV challenges. Post-challenge virus shedding analysis revealed a drastic reduction in NDV shed, as compared to unvaccinated birds.
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http://dx.doi.org/10.3390/pathogens8030145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6789743PMC
September 2019

Infectious bursal disease virus in chickens: prevalence, impact, and management strategies.

Vet Med (Auckl) 2019 5;10:85-97. Epub 2019 Aug 5.

Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243122, India.

Infectious bursal disease (IBD), also known as Gumboro disease, is a highly contagious, immunosuppressive disease of young chickens. Although first observed about 60 years ago, to date, the disease is responsible for major economic losses in the poultry industry worldwide. IBD virus (IBDV), a double-stranded RNA virus, exists as two serotypes with only serotype 1 causing the disease in young chickens. The virus infects the bursa of Fabricius of particularly the actively dividing and differentiating lymphocytes of the B-cells lineage of immature chickens, resulting in morbidity, mortality, and immunosuppression. Immunosuppression enhances the susceptibility of chickens to other infections and interferes with vaccination against other diseases. Immunization is the most important measure to control IBD; however, rampant usage of live vaccines has resulted in the evolution of new strains. Although the immunosuppression caused by IBDV is more directed toward the B lymphocytes, the protective immunity in birds depends on inducement of both humoral and cell-mediated immune responses. The interference with the inactivated vaccine induced maternally derived antibodies in young chicks has become a hurdle in controlling the disease, thus necessitating the development of newer vaccines with improved efficacy. The present review illustrates the overall dynamics of the virus and the disease, and the recent developments in the field of virus diagnosis and vaccine research.
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http://dx.doi.org/10.2147/VMRR.S185159DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6689097PMC
August 2019

Evaluation of a fusion gene-based DNA prime-protein boost vaccination strategy against Newcastle disease virus.

Trop Anim Health Prod 2019 Nov 18;51(8):2529-2538. Epub 2019 Jun 18.

Recombinant DNA Laboratory, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly, UP, 243122, India.

The low potency of genetic immunization has to date impeded development of commercial vaccines against major infectious diseases. The aim of this study was to develop and evaluate a fusion gene-based DNA prime-protein boost vaccination strategy to improve the efficacy of both DNA and subunit vaccines against Newcastle disease virus (NDV). The fusion (F) protein, a viral surface glycoprotein, is responsible for the cell membrane fusion and spread, also is one of the major targets for immune response. In this study, groups of chickens were vaccinated twice intramuscularly at 14-day interval either with plasmid DNA encoding F protein gene of NDV or with recombinant F protein alone or with plasmid DNA and boosted with the recombinant F protein and compared with birds that were vaccinated with live NDV vaccine. The immune response was evaluated by indirect ELISA, lymphocyte transformation test, virus neutralization test, cytokine analysis, immunophenotyping of peripheral blood mononuclear cells, and protective efficacy study against virulent NDV challenge virus infection. Chickens in prime-boost group developed a higher level of humoral and cellular immune responses as compared with those immunized with plasmid or protein alone. The DNA prime-protein boost using F protein of NDV yielded 91.6% protection against virulent NDV challenge infection better than immunization with DNA vaccine (66.6%) or rF protein (83.3%) alone. These findings suggest that the "DNA prime-protein boost" approach using full-length F gene could enhance the immune response against NDV in the chickens.
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http://dx.doi.org/10.1007/s11250-019-01967-2DOI Listing
November 2019

Combination of TLR2 and TLR3 agonists derepress infectious bursal disease virus vaccine-induced immunosuppression in the chicken.

Sci Rep 2019 06 3;9(1):8197. Epub 2019 Jun 3.

Immunology Section, ICAR - Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, (243 122), India.

Live intermediate plus infectious bursal disease virus (IBDV) vaccines (hot vaccines) are used for protection against the virulent IBDV strains in young chickens. We evaluated the potential of Toll-like receptor (TLR) agonists to alleviate hot vaccine-induced immunosuppression. The combination of Pam3CSK4 and poly I:C synergistically upregulated IFN-β, IFN-γ, IL-12, IL-4, and IL-13 transcripts and cross-inhibited IL-1β, IL-10, and iNOS transcripts in the chicken peripheral blood mononuclear cells (PBMCs) as analyzed by quantitative real-time PCR. Further, four-week old specific pathogen free White Leghorn chickens (n = 60) were randomly divided into six groups and either immunized with hot IBDV vaccine with or without Pam3CSK4 and/or poly I:C or not vaccinated to serve as controls. The results indicated that poly I:C alone and in combination with Pam3CSK4 alleviated vaccine-induced immunosuppression, as evidenced by greater weight gain, increased overall antibody responses to both sheep erythrocytes and live infectious bronchitis virus vaccine, upregulated IFN-γ transcripts and nitric oxide production by PBMCs (P < 0.05), and lower bursal lesion score in the experimental birds. In conclusion, poly I:C alone and its combination with Pam3CSK4 reduced the destruction of B cells as well as bursal damage with restoration of function of T cells and macrophages when used with a hot IBDV vaccine.
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http://dx.doi.org/10.1038/s41598-019-44578-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547722PMC
June 2019

Serological profiling of rabies antibodies by enzyme-linked immunosorbent assay and its comparative analysis with rapid fluorescent focus inhibition test in mouse model.

Vet World 2019 Jan 23;12(1):126-130. Epub 2019 Jan 23.

Recombinant DNA Laboratory, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India.

Aim: In this study, we have used enzyme-linked immunosorbent assay (ELISA) as an alternative test to replace the cumbersome rapid fluorescent focus inhibition test (RFFIT) to ascertain the immune status of immunized mice against rabies virus.

Materials And Methods: Rabies is a devastating disease worldwide caused by rabies virus. Proper usage of pre- or post-exposure rabies vaccine can prevent the disease transmission. In this study, mice were immunized with Vero cell-adapted inactivated rabies vaccine. RFFIT was used as a test to determine the serum neutralizing titers in infected/vaccinated mice. Seroprofiling of mice sera was done by ELISA.

Results: Twenty-one days post-immunization, both ELISA and RFFIT assays indicated similar antibody levels in mice sera that were immunized with Vero cell-adapted inactivated rabies vaccine. Both the tests were correlated, and the linearity was verified by the regression line (R²=0.979).

Conclusion: In this study, we profiled the serological status of Vero cell-adapted inactivated rabies vaccine through ELISA in mice model that correlated well with the OIE gold standard test RFFIT.
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http://dx.doi.org/10.14202/vetworld.2019.126-130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6431817PMC
January 2019

Resiquimod enhances mucosal and systemic immunity against avian infectious bronchitis virus vaccine in the chicken.

Microb Pathog 2018 Jun 7;119:119-124. Epub 2018 Apr 7.

Immunology Section, ICAR - Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243 122, India. Electronic address:

Adjuvant enhancing mucosal immune response is preferred in controlling many pathogens at the portal of entry. Earlier, we reported that a toll-like-receptor 7 (TLR7) agonist, resiquimod (R-848), stimulated the systemic immunity when adjuvanted with the inactivated Newcastle disease virus vaccine in the chicken. Here, we report the effect of R-848 when adjuvanted with live or inactivated avian infectious bronchitis virus (IBV) vaccines with special emphasis on mucosal immunity. Specific pathogen free (SPF) chicks (n = 60) were equally divided into six groups at two weeks of age and immunized with either inactivated or live IBV vaccine adjuvanted with or without R-848. Groups that received either PBS or R-848 served as control. A booster was given on 14 days post-immunization (dpi). R-848 enhanced the antigen specific humoral and cellular immune responses when co-administered with the vaccines as evidenced by an increase in the antibody titre in ELISA and stimulation index in lymphocyte transformation test (LTT) till 35 dpi and increased proportion of CD4 and CD8 T cells on 21 dpi in the flow cytometry. Interestingly, it potentiated the IgA responses in the tear and intestinal secretions when used with both live and inactivated IBV vaccines. The combination of IBV vaccine with R-848 significantly up-regulated the transforming growth factor beta 4 (TGFβ4) transcripts in the peripheral blood mononuclear cells (PBMCs) than that of the respective vaccine per se. An enhanced secretory IgA response is likely due to the up-regulation of TGFβ4, which is responsible for class switching to IgA. In conclusion, co-administration of R-848 with inactivated or live IBV vaccine enhanced the systemic as well as mucosal immune responses in the chicken.
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http://dx.doi.org/10.1016/j.micpath.2018.04.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7127065PMC
June 2018

Generation and evaluation of a recombinant Newcastle disease virus strain R2B with an altered fusion protein cleavage site as a vaccine candidate.

Microb Pathog 2018 May 22;118:230-237. Epub 2018 Mar 22.

Recombinant DNA Laboratory, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122 (UP), India. Electronic address:

Newcastle disease (ND) is a highly contagious and fatal disease of chickens. Newcastle disease virus (NDV) strain R2B is an Indian mesogenic strain used for secondary vaccination in chickens. Mesogenic strains have increased virulence and immunogenicity but may cause disease in vaccinated birds, thus rendering them ineffective for use. In this study, we generated a recombinant NDV by changing the fusion protein cleavage site of mesogenic rNDV-R2B from a polybasic amino acid motif RRQKRF to a dibasic amino acid motif GRQGRL leading to generation of an attenuated virus, rNDV-R2B-FPCS. The modified recombinant virus had similar growth characteristics as rNDV-R2B, but was less virulent in susceptible chickens. Immunization of the recombinant attenuated virus to one week of age SPF chickens generated a protective immune response with a substantial reduction in virus shed after challenge with virulent NDV. The results of the study indicate that the modified rNDV-R2B-FPCS virus can be used for primary immunization in birds without any adverse reactions.
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http://dx.doi.org/10.1016/j.micpath.2018.03.038DOI Listing
May 2018

Newcastle Disease Virus Vectored Bivalent Vaccine against Virulent Infectious Bursal Disease and Newcastle Disease of Chickens.

Vaccines (Basel) 2017 Sep 26;5(4). Epub 2017 Sep 26.

Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD 21202, USA.

Newcastle disease virus (NDV) strain F is a lentogenic vaccine strain used for primary vaccination in day-old chickens against Newcastle disease (ND) in India and Southeast Asian countries. Recombinant NDV-F virus and another recombinant NDV harboring the major capsid protein VP2 gene of a very virulent infectious bursal disease virus (IBDV); namely rNDV-F and rNDV-F/VP2, respectively, were generated using the NDV F strain. The rNDV-F/VP2 virus was slightly attenuated, as compared to the rNDV-F virus, as evidenced from the mean death time and intracerebral pathogenicity index analysis. This result indicates that rNDV-F/VP2 behaves as a lentogenic virus and it is stable even after 10 serial passages in embryonated chicken eggs. When chickens were vaccinated with the rNDV F/VP2, it induced both humoral and cell mediated immunity, and was able to confer complete protection against very virulent IBDV challenge and 80% protection against virulent NDV challenge. These results suggest that rNDV-F could be an effective and inherently safe vaccine vector. Here, we demonstrate that a bivalent NDV-IBDV vaccine candidate generated by reverse genetics method is safe, efficacious and cost-effective, which will greatly aid the poultry industry in developing countries.
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http://dx.doi.org/10.3390/vaccines5040031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5748598PMC
September 2017

Rescue of a recombinant Newcastle disease virus strain R2B expressing green fluorescent protein.

Virus Genes 2017 Jun 9;53(3):410-417. Epub 2017 Feb 9.

Institute of Marine and Environmental Technology, University of Maryland, Baltimore County, Baltimore, MD, USA.

Newcastle disease virus (NDV), strain R2B is a mesogenic vaccine strain used for booster vaccination in chickens against Newcastle disease in India and many south East Asian countries. A full-length cDNA clone of the virus was generated by ligating eight overlapping fragments generated by reverse transcription polymerase chain reaction having unique restriction enzyme sites within them. This full-length cDNA clone was flanked by hammerhead ribozyme and hepatitis delta virus ribozyme sequences. Defined genetic markers were introduced into the NDV genome to differentiate the rescued virus from the parent virus. A gene cassette containing the reporter gene, green fluorescent protein flanked by NDV gene-start and gene-end signals was generated by PCR and introduced into the full-length clone of NDV between the P and M genes. Recombinant NDV encoding the GFP gene was rescued having precise termini when transfected into permissive Vero cells along with support plasmids harbouring the nucleoprotein, phosphoprotein and polymerase genes. The recombinant virus had similar growth kinetics as that of the parent virus with a moderate reduction in the virulence. The generation of reverse genetics system for NDV strain R2B will help in the development of multivalent vaccines against viral diseases of livestock and poultry.
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http://dx.doi.org/10.1007/s11262-017-1433-3DOI Listing
June 2017

DNA Vaccination in Chickens.

Methods Mol Biol 2016 ;1404:165-178

Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122, India.

Robust and sustainable development of poultry industry requires prevention of deadly infectious diseases. Vigorous vaccination of the birds is a routine practice; however, the live and inactivated vaccines that are used have inherent disadvantages. New-generation vaccines such as DNA vaccines offer several advantages over conventional vaccines. DNA vaccines, which encode an antigen of interest or multiple antigens in the target host, are stable, easy to produce and administer, do not require cold chain maintenance, and are not affected by the maternal antibodies. In addition, DNA vaccines can also be administered in ovo, and thus, mass vaccination and early induction of immune response can effectively be achieved. In this chapter, we focus on the development of DNA vaccines against important infectious viral as well as parasitic diseases of poultry.
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http://dx.doi.org/10.1007/978-1-4939-3389-1_11DOI Listing
December 2016

Synergy of lipopolysaccharide and resiquimod on type I interferon, pro-inflammatory cytokine, Th1 and Th2 response in chicken peripheral blood mononuclear cells.

Mol Immunol 2015 Mar 9;64(1):177-82. Epub 2014 Dec 9.

Division of Animal Reproduction, IVRI, Izatnagar, Bareilly, Uttar Pradesh 243 122, India.

Toll-like receptors (TLRs) recognize conserved molecular structures of invading pathogens and initiate an immune response to curtail the infection prior to the development of more powerful and specific adaptive immunity. Understanding the interactions between different TLRs in terms of immune response genes is a pre-requisite for using various TLR agonists alone or in combination as adjuvants or as stand-alone agents against various diseases. Lipopolysaccharide (LPS) and resiquimod (R-848) are TLR agonists that are recognized by TLR4 and TLR7, respectively. In this study, the effect of LPS and/or R-848 on chicken peripheral blood mononuclear cells (PBMCs) was investigated. LPS and R-848 synergistically up-regulated the transcripts of interferon-β (IFN-β), IFN-γ, IL-4 and IL-1β as compared to the individual response (P<0.05). The results indicate that these agonists synergistically interact and enhance type-I IFN, pro-inflammatory cytokine as well as Th1 and Th2 responses in chicken PBMCs, suggesting their potential as an adjuvant candidate to be used in combination with various poultry vaccines.
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http://dx.doi.org/10.1016/j.molimm.2014.11.013DOI Listing
March 2015

Genetic characterization and pathogenicity assessment of Newcastle disease virus isolated from wild peacock.

Virus Genes 2014 Dec 27;49(3):449-55. Epub 2014 Sep 27.

Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.

The continued spread and occurrence of Newcastle disease virus (NDV) has posed potential threat to domestic poultry industry around the globe. Mainly, wild avian species has always been implicated for the natural reservoir for virus and spread of the disease. In the present study, we report the isolation of Newcastle disease virus (NDV/Peacock/India/2012) in necropsy brain tissue sample of wild peacock from North India. Complete genome of the virus was found to be 15,186 nucleotides (nts) with six genes in order of 3'-N-P-M-F-HN-L-5', which was limited by 55-nts leader region at the 3' end and a 114-nts trailer sequence at 5' end. Sequence analysis of fusion protein revealed the dibasic amino acid cleavage site (112)R-R-Q-K-R-F(117), a characteristic motif of virulent virus. Phylogenetic analysis placed the isolate in genotype II of Newcastle disease virus showing the lowest mean percent divergence (6 %) with other genotype II counterparts. The isolate was characterized as mesogenic (intermediate pathotype) based on the mean death time (63 h) in embryonated chicken eggs and the intra-cerebral pathogenicity index (1.40) in day-old chicks. The report emphasizes the dynamic ecology of NDV strains circulating in a wild avian host during the outbreak of 2012 in North India. Further the genotypic and pathotypical characterizations of the isolate could help in development of homologous vaccine against NDV strain circulating in avian population.
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http://dx.doi.org/10.1007/s11262-014-1116-2DOI Listing
December 2014

Complete Genome Sequence of a Newcastle Disease Virus Isolated from Wild Peacock (Pavo cristatus) in India.

Genome Announc 2014 Jun 5;2(3). Epub 2014 Jun 5.

Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India

We report here the complete genome sequence of a Newcastle disease virus (NDV) isolated from a wild peacock. Phylogenetic analysis showed that it belongs to genotype II, class II of NDV strains. This study helps to understand the ecology of NDV strains circulating in a wild avian host of this geographical region during the outbreak of 2012 in northwest India.
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http://dx.doi.org/10.1128/genomeA.00495-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4047447PMC
June 2014

Genotype characterization of commonly used Newcastle disease virus vaccine strains of India.

PLoS One 2014 4;9(6):e98869. Epub 2014 Jun 4.

Institute of Marine and Environmental Technology, University of Maryland, Baltimore County, Baltimore, Maryland, United States of America.

Newcastle disease is an avian pathogen causing severe economic losses to the Indian poultry industry due to recurring outbreaks in vaccinated and unvaccinated flocks. India being an endemic country, advocates vaccination against the virus using lentogenic and mesogenic strains. Two virus strains which are commonly used for vaccination are strain F (a lentogenic virus) and strain R2B (a mesogenic virus). Strain F is given to 0-7 days old chicks and R2B is given to older birds which are around 6-8 weeks old. To understand the genetic makeup of these two strains, a complete genome study and phylogenetic analysis of the F, HN genes of these vaccine strains were carried out. Both the viral strains had a genome length of 15,186 nucleotides and consisted of six genes with conserved complimentary 3' leader and 5' trailer regions. The fusion protein cleavage site of strain F is GGRQGRL and strain R2B is RRQKRF. Although both the viral strains had different virulence attributes, the length of the HN protein was similar with 577 amino acids. Phylogenetic analysis of F, HN and complete genome sequences grouped these two strains in genotype II category which are considered as early genotypes and corroborated with their years of isolation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0098869PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4045777PMC
August 2015

Toll-like receptor-based adjuvants: enhancing the immune response to vaccines against infectious diseases of chicken.

Expert Rev Vaccines 2014 Jul 23;13(7):909-25. Epub 2014 May 23.

Division of Veterinary Biotechnology, Recombinant DNA Lab, Indian Veterinary Research Institute, Izatnagar, Bareilly-243122, UP, India.

Huge productivity loss due to infectious diseases in chickens is a major problem and, hence, robust development of the poultry industry requires control of poultry health. Immunization using vaccines is routine practice; however, to combat infectious diseases, conventional vaccines as well as new-generation recombinant vaccines alone, due to relatively weak immunogenicity, may not be effective enough to provide optimum immunity. With this in mind, there is a need to incorporate better and more suitable adjuvants in the vaccines to elicit the elevated immune response in the host. Over last few decades, with the increase in the knowledge of innate immune functioning, efforts have been made to enhance vaccine potency using novel adjuvants like Toll-like receptor based adjuvant systems. In this review, we will discuss the potential use of toll-like receptor ligands as an adjuvant in vaccines against the infectious diseases of chickens.
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http://dx.doi.org/10.1586/14760584.2014.920236DOI Listing
July 2014

Flagellin a toll-like receptor 5 agonist as an adjuvant in chicken vaccines.

Clin Vaccine Immunol 2014 Mar 22;21(3):261-70. Epub 2014 Jan 22.

Recombinant DNA Lab, Indian Veterinary Research Institute, Izatnagar, Bareilly (UP), India.

Chicken raised under commercial conditions are vulnerable to environmental exposure to a number of pathogens. Therefore, regular vaccination of the flock is an absolute requirement to prevent the occurrence of infectious diseases. To combat infectious diseases, vaccines require inclusion of effective adjuvants that promote enhanced protection and do not cause any undesired adverse reaction when administered to birds along with the vaccine. With this perspective in mind, there is an increased need for effective better vaccine adjuvants. Efforts are being made to enhance vaccine efficacy by the use of suitable adjuvants, particularly Toll-like receptor (TLR)-based adjuvants. TLRs are among the types of pattern recognition receptors (PRRs) that recognize conserved pathogen molecules. A number of studies have documented the effectiveness of flagellin as an adjuvant as well as its ability to promote cytokine production by a range of innate immune cells. This minireview summarizes our current understanding of flagellin action, its role in inducing cytokine response in chicken cells, and the potential use of flagellin as well as its combination with other TLR ligands as an adjuvant in chicken vaccines.
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http://dx.doi.org/10.1128/CVI.00669-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3957660PMC
March 2014

Complete genome sequence of Newcastle disease virus mesogenic vaccine strain R2B from India.

J Virol 2012 Dec;86(24):13814-5

Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India.

Mesogenic vaccine strains of Newcastle disease virus (NDV) are widely used in many countries of Asia and Africa to control the Newcastle disease of poultry. In India, the mesogenic strain R2B was introduced in 1945; it protects adult chickens that have been preimmunized with a lentogenic vaccine virus and provides long-lasting immunity. In this article, we report the complete genome sequence of the hitherto unsequenced Indian vaccine virus strain R2B. The viral genome is 15,186 nucleotides in length and contains the polybasic amino acid motif in the fusion protein cleavage site, indicating that this vaccine strain has evolved from a virulent virus. Phylogenetic analysis of this mesogenic vaccine virus classified it with the viruses belonging to genotype III of the class cluster II of NDV.
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http://dx.doi.org/10.1128/JVI.02552-12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3503142PMC
December 2012
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