LaSota Newcastle Disease Virus Research Articles

MicroRNA transcriptome analysis of chicken embryo fibroblast cells infected with Newcastle disease virus variants

Variations in the pathogenicity of Newcastle disease virus (NDV), the agent causing Newcastle disease, are associated with variants of different virulence. A few studies have characterized the expression of microRNAs (miRNAs) in NDV-infected avian cells. Here, the expression of miRNAs in chicken embryo fibroblasts (CEFs) infected with Herts/33 and LaSota NDV strains (highly virulent and nonvirulent, respectively) was determined using RNA sequencing. miRNAs involved in NDV infection included 562 previously documented and 184 novel miRNAs. miRNA target genes involved transcription factors, cell apoptosis, ubiquitin-mediated proteolysis, and protein processing in the endoplasmic reticulum. Potential target genes associated with autophagy were verified by qRT-PCR. No studies have documented the miRNA profiles of CEFs infected with NDVs variants. This study adds to our knowledge of the cellular miRNAs involved in NDV infection and the complex molecular mechanisms mediating virus-host interactions. The results of this study will aid the development of strategies against the chicken virus.

Response of three local chicken ecotypes of Ghana to lentogenic and velogenic Newcastle disease virus challenge.

This study was carried out to assess the response of three Ghanaian local chicken ecotypes to LaSota (lentogenic) and virulent field strains of Newcastle disease virus (NDV). Local chickens sampled from the Interior Savannah (IS), Forest (FO) and Coastal Savannah (CS) agro-ecological zones were bred and their offspring were challenged with LaSota NDV at 4weeks of age. The LaSota challenge was replicated four times with different chicken groups. A total of 1438 chicks comprising 509 Coastal Savannah, 518 Forest and 411 Interior Savannah ecotypes were used. Pre- and post-challenge anti-NDV antibody titre levels were determined via ELISA assays. A second trial was conducted by introducing sick birds infected with virulent NDV to a flock of immunologically naïve chickens at 4weeks old. Body weights were measured pre- and post-infection. Sex of the chickens was determined using a molecular method. In both trials, there was no significant difference among ecotypes in body weight and growth rate. In the LaSota trial, anti-NDV antibody titre did not differ by ecotype or sex. However, there was a positive linear relationship between body weight and antibody titre. In the velogenic NDV trial, survivability and lesion scores were similar among the three ecotypes. This study confirms that a relatively high dose of LaSota (NDV) challenge has no undesirable effect on Ghanaian local chicken ecotypes. All three Ghanaian local chicken ecotypes were susceptible to velogenic NDV challenge. Resistance to NDV by Ghanaian local chickens appears to be determined more by the individual's genetic makeup than by their ecotype.

Thymic transcriptome analysis after Newcastle disease virus inoculation in chickens and the influence of host small RNAs on NDV replication

Newcastle disease (ND), caused by virulent Newcastle disease virus (NDV), is a contagious viral disease affecting various birds and poultry worldwide. In this project, differentially expressed (DE) circRNAs, miRNAs and mRNAs were identified by high-throughput RNA sequencing (RNA-Seq) in chicken thymus at 24, 48, 72 or 96 h post LaSota NDV vaccine injection versus pre-inoculation group. The vital terms or pathways enriched by vaccine-influenced genes were tested through KEGG and GO analysis. DE genes implicated in innate immunity were preliminarily screened out through GO, InnateDB and Reactome Pathway databases. The interaction networks of DE innate immune genes were established by STRING website. Considering the high expression of gga-miR-6631-5p across all the four time points, DE circRNAs or mRNAs with the possibility to bind to gga-miR-6631-5p were screened out. Among DE genes that had the probability to interact with gga-miR-6631-5p, 7 genes were found to be related to innate immunity. Furthermore, gga-miR-6631-5p promoted LaSota NDV replication by targeting insulin induced gene 1 (INSIG1) in DF-1 chicken fibroblast cells. Taken together, our data provided the comprehensive information about molecular responses to NDV LaSota vaccine in Chinese Partridge Shank Chickens and elucidated the vital roles of gga-miR-6631-5p/INSIG1 axis in LaSota NDV replication.

In Vitro Oncolytic activity of non-virulent Newcastle Disease Virus LaSota Strain against Mouse mammary adenocarcinoma

Newcastle disease virus (NDV) is a wide-spectrum anti-tumor agent. The oncolytic selectivity of NDV, a family of Paramyxoviridae, depends on the differential type of inducing different death pathways. This work was conducted to further understand the oncolytic effect of LaSota strain. A mouse breast cancer model (Murine mammary adenocarcinoma cell line AMN3) was used in this study. Methyl Thiazolyl Tetrazolium (MTT) viability assay tested different NDV multiplicity of infection (MOI) values on mouse mammary adenocarcinoma cells incubated for 72 hours post-infection. The IC50 values and anti-tumor activity of LaSota strain against AMN3 cell line were determined. Following Hematoxylin and Eosin Stain, we examined the morphological modifications of IC50 along with 10 MOI values of NDV. The induction of NDV apoptosis in AMN3 cells was investigated using the technique of staining acridine orange and propidium iodide (AO / PI). Immunocytochemistry assay was performed using anti-NDV mAbs and caspases 8 and 9 to study NDV replication and apoptosis induction mechanisms. The lentogenic LaSota NDV strain, a live vaccine, demonstrated the oncolytic effect on mammary cancer cells of the AMN3 mouse and showed that LaSota strain triggered a dose-dependent increase in infected cells’ apoptosis relative to untreated mammary cancer cells. The immunocytochemistry study showed that NDV infected cells were positive for virus infection and that caspase9 in mouse mammary cancer cells after LaSota strain infection was significantly enhanced compared to caspase 8. In conclusions, NDV LaSota strain had oncolytic effects by destroying tumor cells and triggering the intrinsic apoptosis pathways in mouse mammary cancer cells. However, the mechanisms of the in vivo anti-tumor activity need to be better understood.

Development of a recombinant NP protein based indirect ELISA for the detection of antibodies against Newcastle disease virus and differentiation of infected or recombinant vaccine immunized chickens.

Newcastle disease (ND) is a highly contagious and economically important disease in the poultry industry caused by avian avulavirus-1, historically known as Newcastle disease virus (NDV). Control of ND primarily relies on prophylactic vaccination of flocks, and many vaccines are available on the market, both conventional and more recently introduced new generation recombinant types. To assess the protection level achieved by vaccination ELISA tests are typically used, they also are to track an infection with field strains in non-vaccinated flocks. Special modifications of ELISA can be used as a screening tool to detect infection in flocks vaccinated with new generation vaccines. In this study, we have developed an ELISA test for the detection of antibodies against the nucleoprotein (NP) of NDV and for differentiation of chickens vaccinated with commercial and prototype in-house recombinant vector vaccines from those infected with field NDV strains. The NP gene of LaSota NDV strain expressed in a baculovirus vector was used as a coating antigen in the ELISA. The developed test was optimized, validated and compared to other serological tests. The sensitivity, specificity and accuracy of recombinant NP protein-based ELISA were respectively 96.1%, 96.3%, and 96.2%. Inter-rater (kappa) agreement between the NP-ELISA and the gold standard HI test was calculated to be 0.995. In our comparisons, commercially available ELISA tests revealed different specificities ranging from 95.5-100% and sensitivities at variance, ranging from 90.1 to 99.0%. A high level of maternally derived antibodies was measured in the serum of 1-day-old broilers in the NP-ELISA assay. These antibodies had disappeared and were undetected at 3, 5 and 6 weeks post-vaccination but birds became positive again at 2 weeks after control infection with a velogenic NDV strain. In SPF chickens, antibodies against NP protein were detected only after a challenge. The recombinant NP protein-based ELISA test is sensitive, specific and accurate when compared to the gold standard HI test and commercially available kits. Moreover, the method could be also used for the differentiation between vaccinated and infected birds.

Isolation and Identification of Wild Isolate of Newcastle Disease Virus from Broiler Farm in Diyala Province: Virological and Histopathological Study

A broiler poultry farm of six weeks old, vaccinated with LaSota Newcastle disease virus vaccine. The flock was infected with a virulent Newcastle disease virus with mortality rate up to 90%. Newcastle disease virus was isolated from infected birds in embryonated chicken eggs and identified by haemagglutination inhibition test using hyperimmune serum prepared against LaSota viral vaccine. Median Death Time, Intracerebral Pathogenicity Index and Intravenous Pathogenicity Index proved that the virus was a virulent viscerotropic isolate. In experimental infection, broilers were vaccinated twice with LaSota strain, the level of anti-Newcastle disease virus IgG was checked by Enzyme-linked immunosorbent assay test pre and post vaccination and the birds were challenged with the same isolated virulent isolate at 35 days old, the virus was inoculated by oral and nostril routs. The challenge virus produced the same sever clinical signs and the mortality rate reached up to 70%. Tissue samples were collected from intestine, kidneys, lung, trachea, spleen, liver, and the brain of the experimentally infected broilers, they showed sever pathological changes. It seems that vaccination with commercial available vaccine could not produce enough protection against virulent circulating Newcastle disease virus strains, accordingly preparation of viral vaccine from local virulent isolate is recommended after attenuation or inactivation.

Transcriptome Analysis in Spleen Reveals Differential Regulation of Response to Newcastle Disease Virus in Two Chicken Lines

Enhancing genetic resistance of chickens to Newcastle Disease Virus (NDV) provides a promising way to improve poultry health, and to alleviate poverty and food insecurity in developing countries. In this study, two inbred chicken lines with different responses to NDV, Fayoumi and Leghorn, were challenged with LaSota NDV strain at 21 days of age. Through transcriptome analysis, gene expression in spleen at 2 and 6 days post-inoculation was compared between NDV-infected and control groups, as well as between chicken lines. At a false discovery rate <0.05, Fayoumi chickens, which are relatively more resistant to NDV, showed fewer differentially expressed genes (DEGs) than Leghorn chickens. Several interferon-stimulated genes were identified as important DEGs regulating immune response to NDV in chicken. Pathways predicted by IPA analysis, such as "EIF-signaling", "actin cytoskeleton organization nitric oxide production" and "coagulation system" may contribute to resistance to NDV in Fayoumi chickens. The identified DEGs and predicted pathways may contribute to differential responses to NDV between the two chicken lines and provide potential targets for breeding chickens that are more resistant to NDV.

66. Recombinant Newcastle Disease Virus as an Oncolytic Therapy for Ovarian and Prostate Cancers

Newcastle disease virus (NDV) is a member of the Avulavirus genus in the Paramyxoviridae family. NDV selectively replicates in tumor cells due to defects in antiviral and apoptotic signalling. It is the oncolytic virus with the longest history of use in clinical trials with a proven safety record as a monotherapy due to its strong induction of antiviral responses in non-transformed mammalian cells. In addition to its direct oncolytic effect, NDV also activates both innate and adaptive immune responses and therefore has strong immunotherapeutic potential. To enhance the fusogenicity of the virus, the fusion protein of recombinant LaSota NDV (rNDV) was engineered to express a multibasic cleavage and activation site (rNDV/F3aa). This virus is highly fusogenic leading to the formation of large syncytia that allows for efficient intratumoral spread and increased lytic potential. While NDV has demonstrated efficacy in a number of different cancer models, including melanoma and hepatocellular carcinoma, little information about its efficacy in ovarian and prostate cancer is available. To this end, we evaluated the oncolytic potential of rNDV/F3aa expressing enhanced green fluorescent protein (GFP) in a panel of prostate and ovarian cancer cell lines using a resazurin dye-based cell viability assay. Infection with rNDV/F3aa-GFP at a range of MOIs significantly reduced the viability of these cancer cells in vitro, but had little effect on normal untransformed cells. To evaluate the efficacy of NDV in vivo, we used a well-established orthotopic mouse model of epithelial ovarian cancer and a syngeneic murine RM9 prostate carcinoma model. Intravenous delivery of 1×10^8 PFU of rNDV/F3aa-GFP to ovarian tumor-bearing mice resulted in a significant reduction in the primary tumor size and number of metastatic abdominal tumours. Furthermore, 50% of the mice had a complete loss of ascites, which is an accumulation of fluid in the abdomen, as a result of advanced stage ovarian cancer. The apparent decrease in secondary disease after treatment with rNDV/F3aa-GFP is particularly promising as it is the metastatic lesions that ultimately cause high morbidity and mortality in patients with advanced ovarian cancers. A pilot study in the RM9 prostate model revealed that rNDV/F3aa-GFP was able to replicate and spread within the tumor and neovasculature after intratumoral or intravenous delivery of 1×10^8 PFU. Studies to confirm these results, as well as to evaluate the ability of rNDV/F3aa-GFP to induce tumor regression and increase survival are currently underway. Taken together, these data suggest that NDV/F3aa is a promising oncolytic for further development as an anti-cancer agent for the treatment of prostate and ovarian cancers.

Development of a low-dose fast-dissolving tablet formulation of Newcastle disease vaccine for low-cost backyard poultry immunisation

The immunisation of backyard poultry is critical for maintaining healthy flocks to provide nutrition and income for low-resource farmers worldwide. A vaccine presentation for flocks of less than 50 birds...

Pathologic Characterization of Genotypes XIV and XVII Newcastle Disease Viruses and Efficacy of Classical Vaccination on Specific Pathogen-Free Birds

To characterize the clinicopathologic features of recently described genotypes of Newcastle disease virus (NDV), 1 representative strain of genotype XIV and 2 of genotype XVII, all isolated from West Africa, were used to infect groups of ten 4-week-old specific pathogen-free chickens. The pathobiology of these 3 strains was compared to a South African NDV strain classified within genotype VII. All chickens infected with the 4 viruses died or were euthanized by day 4 postinfection due to the severity of clinical signs. Gross and histologic lesions in all infected chickens included extensive necrosis of lymphoid tissues (thymus, spleen, bursa of Fabricius, cecal tonsils, gut-associated lymphoid tissue), gastrointestinal necrosis and hemorrhages, and severe hemorrhagic conjunctivitis. Immunohistochemical staining revealed systemic viral distribution, and the most intense staining was in the lymphoid organs. Results demonstrate that the 3 West African strains from the previously uncharacterized genotypes XIV and XVII are typical velogenic viscerotropic NDV strains with lesions similar to the South African strain. Under experimental conditions, QV4 and LaSota NDV vaccine strains successfully protected chickens from morbidity and mortality against the genotype VII and one genotype XVII NDV strain, with no significant differences in the amount of virus shed when 2 vaccine schemes were compared.

Cross-protective immunity against influenza A/H1N1 virus challenge in mice immunized with recombinant vaccine expressing HA gene of influenza A/H5N1 virus

BackgroundInfluenza virus undergoes constant antigenic evolution, and therefore influenza vaccines must be reformulated each year. Time is necessary to produce a vaccine that is antigenically matched to a pandemic strain. A goal of many research works is to produce universal vaccines that can induce protective immunity to influenza A viruses of various subtypes. Despite intensive studies, the precise mechanisms of heterosubtypic immunity (HSI) remain ambiguous.MethodIn this study, mice were vaccinated with recombinant virus vaccine (rL H5), in which the hemagglutinin (HA) gene of influenza A/H5N1 virus was inserted into the LaSota Newcastle disease virus (NDV) vaccine strain. Following a challenge with influenza A/H1N1 virus, survival rates and lung index of mice were observed. The antibodies to influenza virus were detected using hemagglutination inhibition (HI). The lung viral loads, lung cytokine levels and the percentages of both IFN-γ+CD4+ and IFN-γ+CD8+ T cells in spleen were detected using real-time RT-PCR, ELISA and flow cytometry respectively.ResultsIn comparison with the group of mice given phosphate-buffered saline (PBS), the mice vaccinated with rL H5 showed reductions in lung index and viral replication in the lungs after a challenge with influenza A/H1N1 virus. The antibody titer in group 3 (H1N1-H1N1) was significantly higher than that in other groups which only low levels of antibody were detected. IFN-γ levels increased in both group 1 (rL H5-H1N1) and group 2 (rL H5 + IL-2-H1N1). And the IFN-γ level of group 2 was significantly higher than that of group 1. The percentages of both IFN-γ+CD4+ and IFN-γ+CD8+ T cells in group 1 (rL H5-H1N1) and group 2 (rL H5 + IL-2-H1N1) increased significantly, as measured by flow cytometry.ConclusionAfter the mice were vaccinated with rL H5, cross-protective immune response was induced, which was against heterosubtypic influenza A/H1N1 virus. To some extent, cross-protective immune response can be enhanced by IL-2 as an adjuvant. Cellular immune responses may play an important role in HSI against influenza virus.

Protective Dose of a Recombinant Newcastle Disease LaSota–Avian Influenza Virus H5 Vaccine Against H5N2 Highly Pathogenic Avian Influenza Virus and Velogenic Viscerotropic Newcastle Disease Virus in Broilers with High Maternal Antibody Levels

The protective dose of a live recombinant LaSota Newcastle disease virus (NDV)-avian influenza H5 vaccine (rNDV-LS/AI-H5) was determined in broiler chickens with high levels of maternal antibodies against NDV and avian influenza virus (AIV). At hatch the geometric mean titers (GMT) of the chickens' maternal antibodies were 2(5.1) and 2(10.3) for NDV and AIV, respectively. At the time of vaccination the GMT was 2(3.1) for NDV and 2(7.9) for AIV. The chickens were vaccinated with one drop (0.03 ml) in the eye at 10 days of age as is typical under field conditions. The test chickens received 10(4.8), 10(5.8), 10(6.8), or 10(7.8) mean chicken embryo infective doses (CEID50) of the rNDV-LS/AI-H5 vaccine. Control chickens were either nonvaccinated, or vaccinated with 10(5.8) or 10(6.8) CEID50 of a commercial live LaSota NDV vaccine. Birds were challenged with either the Mexican highly pathogenic avian influenza virus (HPAIV) strain A/Chicken/Queretaro/14588-19/95 (H5N2) or a Mexican velogenic viscerotropic (VV) NDV strain. One hundred percent of the chickens vaccinated with the rNDV-LS/AI-H5 vaccine were protected against HPAIV and VVNDV when a challenge dose of 10(6.8) EID50 or higher was administered by eye drop. Birds vaccinated with the LaSota NDV vaccine were protected against VVNDV, but not against HPAIV.

Generation and Evaluation of a Newcastle Disease Virus–Based H9 Avian Influenza Live Vaccine

Infection with H9 avian influenza virus (AIV) and Newcastle disease virus (NDV) are two important causes of egg drop in layer and breeder poultry, leading to severe economic loss in the industry. Currently in China, inactivated H9 AIV vaccine and live attenuated NDV vaccine have to be repeatedly administered to prevent egg drop in layer animals. Using reverse genetics, we constructed a recombinant NDV expressing an H9 AIV hemagglutinin (HA) from an H9N2 field isolate, A/Chicken/ Shandong/2/2007. The HA gene was inserted into the intergenic region between the phosphoprotein (P) and matrix (M) genes of the LaSota NDV vaccine strain. The recombinant virus stably expressing the HA gene, rL-H9, was found to be innocuous after intracerebral inoculation of 1-day-old chickens. A single dose of 10(6) 50% egg infectious dose of the recombinant virus intranasally inoculated into chickens induced high levels of NDV- and AIV H9-specific hemagglutination-inhibition antibody. Complete protection from clinical disease and mortality against challenge with a lethal dose of velogenic NDV was observed in chickens and 90% of chickens were protected from clinical disease, mortality, and virus shedding against challenge with homologous H9N2 AIV. Our results suggest that recombinant NDV is suitable as a potential bivalent live attenuated vaccine against both NDV and H9 AIV infection in poultry.

Newcastle Disease Virus-Based Live Attenuated Vaccine Completely Protects Chickens and Mice from Lethal Challenge of Homologous and Heterologous H5N1 Avian Influenza Viruses

H5N1 highly pathogenic avian influenza virus (HPAIV) has continued to spread and poses a significant threat to both animal and human health. Current influenza vaccine strategies have limitations that prevent their effective use for widespread inoculation of animals in the field. Vaccine strains of Newcastle disease virus (NDV), however, have been used successfully to easily vaccinate large numbers of animals. In this study, we used reverse genetics to construct a NDV that expressed an H5 subtype avian influenza virus (AIV) hemagglutinin (HA). Both a wild-type and a mutated HA open reading frame (ORF) from the HPAIV wild bird isolate, A/Bar-headed goose/Qinghai/3/2005 (H5N1), were inserted into the intergenic region between the P and M genes of the LaSota NDV vaccine strain. The recombinant viruses stably expressing the wild-type and mutant HA genes were found to be innocuous after intracerebral inoculation of 1-day-old chickens. A single dose of the recombinant viruses in chickens induced both NDV- and AIV H5-specific antibodies and completely protected chickens from challenge with a lethal dose of both velogenic NDV and homologous and heterologous H5N1 HPAIV. In addition, BALB/c mice immunized with the recombinant NDV-based vaccine produced H5 AIV-specific antibodies and were completely protected from homologous and heterologous lethal virus challenge. Our results indicate that recombinant NDV is suitable as a bivalent live attenuated vaccine against both NDV and AIV infection in poultry. The recombinant NDV vaccine may also have potential use in high-risk human individuals to control the pandemic spread of lethal avian influenza.

Nucleotide Sequence and Vaccinia Expression of the Nucleoprotein of a Highly Virulent, Neurotropic Strain of Newcastle Disease Virus

The nucleoprotein (NP) of Newcastle disease virus (NDV) was selected to study the relative importance of an internal structural protein in the avian immune response. The NP gene of the virulent, neurotropic NDV Texas GB (TGB) strain was cloned and sequenced. Nucleotide sequence data for the NP gene allowed comparison of the deduced amino acid sequences for the NP genes of NDV-TGB and the avirulent duck isolate NDV-D26. These comparisons demonstrated an 89% nucleotide sequence homology and a 97% homology between the deduced amino acid sequences. The NDV-TGB NP expressed in recombinant vaccinia virus (rVAC) was electrophoretically and immunologically identical to the wild-type NDV-TGB. Although inoculation of chickens with the recombinant vaccinia virus expressing the NDV NP gene elicited anti-NDV antibodies in higher titers than in birds inoculated with live LaSota NDV, this strong anti-NDV response did not protect against lethal challenge with NDV-TGB.

Comparative Immune Response from Vaccinating Chickens with Lentogenic Newcastle Disease Virus Strains

The immune response of chickens to 11 isolates of LaSota strain Newcastle disease virus (NDV) and to 7 isolates of B1 strain NDV was studied in specific-pathogen-free chickens. Most of the vaccine strains were from commercial vaccine producers. Comparison of immunogenicity were made of these vaccines; five other lentogenic NDV strains, not used commercially, were also evaluated.From the criteria of hemagglutination inhibition (HI) and virus serum (VN) neutralizing titers, differences were observed with certain isolates within the LaSota and B1 vaccine groups. Whereas the majority of vaccine strains fell within a predictable range, some proved considerably less in their ability to engender expected titers. Two- to threefold differences in titers were observed with some of the strains compared.Two cloned LaSota NDV strains did not compare favorably, or with expected higher titers, with uncloned or conventional LaSota strain virus isolates. Similarly, certain B1 and LaSota strains passaged in chickens did not demonstrate a greater immunogenic potential over conventional, commercial vaccines of similar strain designation but not passaged in chickens.Whereas none of the NDV strains demonstrated evidence of neurotropism or lethality, post-vaccination respiratory reactions were difficult, if not impossible, to evaluate in laboratory isolation units. The complexity of selecting ND vaccines for field use is discussed briefly.

Cellular Immune Response in Turkeys Inoculated with Two Antigenically Indistinguishable Avian Influenza-A Viruses

SUMMARY Peripheral blood lymphocytes from two groups of turkeys, each inoculated with one of two antigenically indistinguishable (Hav6 Nav2) strains of avian influenza virus (A/Ty/Ca/6750/73 or A/Ty/ Mass/65), were incubated in vitro with homologous and heterologous strains of AI virus. LaSota Newcastle disease virus and phytohemagglutinin were used as control mitogens. The degree of lymphocyte transformation was determined by measuring the incorporation of (3H)-thymidine. Lymphocytes from turkeys inoculated with AI strain A/Ty/Ca/ 6750/73 showed a greater blastogenesis when treated with the homologous virus than lymphocytes sensitized to A/Ty/Mass/65 and treated in vitro with its homolog. However, lymphocytes from turkeys inoculated with A/Ty/Mass/65 showed considerable blastogenesis when treated in vitro with the heterologous AI virus (A/Ty/ Ca/7650/73), whereas lymphocytes from turkeys inoculated with A/ Ty/Ca/7650/73 showed less stimulation when treated with the heterologous AI virus (A/Ty/Mass/65). The A/Ty/Mass/65 strain of AI was antigenically superior in producing an HI antibody response, suggesting that the humoral and cell immunity are separate immunologic events. The property of an AI strain of virus to stimulate blastogenesis and tissue immunity may become an important factor in selecting a virus for use in vaccine production.

Vaccination of Turkeys against Newcastle Disease

Turkeys given primary vaccination with an inactivated Newcastle (ND) vaccine failed to respond satisfactorily in the serumvirus neutralization test and challenge of immunity via the respiratory tract. Revaccination did not effect a satisfactory anamnestic response. LaSota strain Newcastle disease virus (NDV), however, applied by eyedrop or in drinking water, stimulated excellent immunity by the same criteria. Response was unsatisfactory when LaSota NDV was given intramuscularly. Bl-strain NDV given by eyedrop or drinking water induced good immunity but of lower magnitude than from the LaSota strain. Cell-culture ND vaccine resulted in relatively poor protection from infection of the respiratory tract, and the virus-neutralizing antibody titers were relatively low or marginal. The potential use of lentogenic NDV strains in turkey vaccination programs was discussed.

Newcastle Disease Immunization Studies: 4. Vaccination of Chickens with B1, F and Lasota Strains of Newcastle Disease Virus Administered through the Drinking Water

ABSTRACT PREVIOUS studies have demonstrated the efficacy of immunizing chickens against Newcastle disease (ND) with B1 strain Newcastle disease virus (NDV) administered through the drinking water under laboratory and field conditions (Winterfield and Seadale, 1955Winterfield and Seadale, 1956Winterfield and Seadale, 1957a,b). In this investigation, F and LaSota NDV strains were used as vaccines in addition to the B1. The results are presented in this paper. MATERIALS AND METHODS B1 strain NDV (Hitchner and Johnson, 1948) vaccine was prepared from stock virus maintained in the authors’ laboratory. F strain NDV was obtained in a dry state from the Newcastle Disease Repository, University of Wisconsin, and the LaSota strain was isolated from a commercial vaccine. The F and LaSota strains were passed through three generations in embryonated chicken eggs before being used as vaccines. Each vaccine was in the form of amnioallantoic fluid (AAF) obtained from infected embryos. The same vaccine pool of each strain was used . . .