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J Gelb

Publications and source records attributed to J Gelb.

At least 19 recordsLinked to original sources
PubMed2005

S1 gene characteristics and efficacy of vaccination against infectious bronchitis virus field isolates from the United States and Israel (1996 to 2000).

The S1 genes of isolates of avian coronavirus infectious bronchitis virus (IBV) from commercial chickens in the US and Israel (20 isolates from each country) were studied using reverse transcription-polymerase chain reaction restriction fragment length polymorphism and sequencing. Partial sequences spanning the amino terminus region of S1 from amino acid residues 48 to 219, based on the Beaudette strain, were used for analysis. Phylogenetic clustering and high-sequence identity values were used to identify isolates that appeared to be derived from live IBV vaccines used in the two countries. Novel variant strains, unrelated by S1 sequencing and restriction fragment length polymorphism analyses to reference and vaccine strains, were also identified. Based on S1 sequence identity to available vaccines, the potential to use vaccination to control IBV infections was evaluated. Vaccination with commercial live strains Massachusetts (Mass), Arkansas (Ark) or DE/072/92, generally produced immunity against vaccine-related field isolates displaying high S1 sequence similarities (> or = 90%) to the respective vaccine strains. Immunization with a bivalent vaccine containing the Mass and Ark strains provided good cross-protection, averaging 81% against challenge with five variant isolates from the US having amino acid identity values ranging from 62 to 69% to Mass and from 68 to 83% to Ark, respectively. In contrast, the H120 vaccine strain induced low levels of protection, ranging from 25 to 58% against variant field isolates from Israel with amino acid identity values from 65 to 67%.

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PubMed1987

Detergent-treated Newcastle disease virus as an agar gel precipitin test antigen.

A soluble Newcastle disease virus (NDV) agar gel precipitin (AGP) antigen was prepared by treating 100-fold concentrated NDV with a nonionic detergent. Virus concentration prior to detergent treatment was best accomplished by ultracentrifugation or by a simple, less expensive, and more practical method involving acid (HCl) precipitation of NDV. Virus concentrated by polyethylene glycol precipitation was found to have a low antigen titer and was not considered suitable as an AGP antigen. Antigens derived from the LaSota, Roakin, and Texas GB strains formed at least two lines of identity in the AGP test as early as 24 hr after inoculation of the agar gels. Virus used for AGP antigen production could be grown in chicken embryos from an NDV-immune as well as susceptible breeder flock. The NDV AGP antigen was found to be stable after 20 consecutive freezing and thawing cycles and storage at -20 C or 4 C for at least 6 months. Detergent-treated NDV was used as an AGP test antigen to determine serum antibody responses of chickens following infection and vaccination. Hemagglutination-inhibition, virus neutralization, and enzyme-linked immunosorbent assay antibody production was also evaluated for comparative purposes. The AGP test was found to be useful as an aid in diagnosing field infections and assessing inactivated virus vaccination responses. These purposes were achieved by demonstrating an increase in the number of AGP positive chickens between preinfection and postinfection or vaccination bleedings. The ease of performance and low cost of the AGP test favors its use for screening large numbers of serum samples, perhaps in conjunction with a quantitative serological test.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1980

Comparison of inactivated and live infectious bursal disease virus vaccines in White Leghorn breeder flock.

Leghorn breeder chickens, which had received live infectious bursal disease (IBDV) virus vaccine at 12 weeks of age and had been injected subcutaneously at 20 weeks of age with an inactivated IBDV oil emulsion vaccine, produced very high antibody titers which persisted for at least 9 months and were more uniform than those obtained from breeders receiving only the live IBDV vaccine. Breeders vaccinated with the inactivated IBDV oil emulsion vaccine at 12 and 20 weeks of age had antibody titers higher than breeders which received only the live IBDV vaccine at 12 weeks of age; titers were lower than in the group which received both the live and inactivated oil emulsion IBDV vaccines. Maternal antibody levels in chickens derived from parent flocks vaccinated with the inactivated oil emulsion IBDV vaccine were higher and more uniform than in chickens derived from parent flocks vaccinated with the live IBDV vaccine. Maternal antibody persisted longer in chickens derived from parent flocks vaccinated at 20 weeks of age with the inactivated oil emulsion IBDV vaccine than in chickens vaccinated by the other procedures. The titers remained quite high up to 16 days of age.

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PubMedDate not supplied

Nephropathogenic infectious bronchitis in Pennsylvania chickens 1997-2000.

Nephropathogenic infectious bronchitis (NIB) was diagnosed in 28 infectious bronchitis virus (IBV)-vaccinated commercial chicken flocks in Pennsylvania from December 1997 to July 2000. Early dinical signs were increased flock mortality and urinary water loss (polyuria and pollakiuria) leading to wet litter. Daily mortality ranged from 0.01% in layers to 2.45% in broilers, with total broiler mortality as high as 23%. Severe renal swelling and accumulation of urates in the tubules were commonly seen. Visceral gout and urolithiasis were less frequently observed. Histopathologic changes included characteristic tubular epithelial degeneration and sloughing with lymphoplasmacytic interstitial nephritis. Minimal respiratory disease signs were noted in broilers. Egg production and shell quality declined in layers. Confirmatory diagnosis of NIB was made by IBV antigen-specific immunohistochemical staining of the renal tubular epithelium and virus isolation. Sequencing of the S1 subunit gene of 21 IBV isolates showed the NIB outbreak to be associated with two unique genotypes, PA/Wolgemuth/98 and PA/171/99. The cases from which the genotypes were isolated were clinically indistinguishable. The NIB viruses were unrelated to previously recognized endemic strains in Pennsylvania and were also dissimilar to each other. Genotype PA/Wolgemuth/98 was isolated almost exclusively during the first 14 mo of the outbreak, whereas PA/171/99 was recovered during the final 18 mo. The reason for the apparent replacement of PA/Wolgemuth/98 by PA/171/99 is not known.

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PubMedDate not supplied

Protection of chickens after live and inactivated virus vaccination against challenge with nephropathogenic infectious bronchitis virus PA/Wolgemuth/98.

Protection provided by live and inactivated virus vaccination against challenge with the virulent nephropathogenic infectious bronchitis virus (NIBV) strain PA/Wolgemuth/98 was assessed. Vaccinations with combinations of live attenuated strains Massachusetts (Mass) + Connecticut (Conn) or Mass + Arkansas (Ark) were given by eyedrop to 2-wk-old specific-pathogen-free leghorn chickens. After live infectious bronchitis virus (IBV) vaccination, some chickens at 6 wk of age received an injection of either an oil emulsion vaccine containing inactivated IBV strains Mass + Ark or an autogenous vaccine prepared from NIBV PA/Wolgemuth/98. Challenge with PA/Wolgemuth/98 was given via eyedrop at 10 wk of age. Serum IBV enzyme-linked immunosorbent assay antibody geometric mean titers (GMTs) after vaccination with the combinations of live attenuated strains were low, ranging from 184 to 1,354, prior to NIBV challenge at 10 wk of age. Both inactivated vaccines induced an anamnestic response of similar magnitudes with serum GMTs of 6,232-12,241. Assessment of protection following NIBV challenge was based on several criteria virus reisolation from trachea and kidney and renal microscopic pathology and IBV-specific antigen immunohistochemistry (IHC). Live attenuated virus vaccination alone with combinations of strains Mass + Conn or Mass + Ark did not protect the respiratory tract and kidney of chickens after PA/Wolgemuth/98 challenge. Chickens given a live combination vaccination of Mass + Conn and boosted with an inactivated Mass + Ark vaccine were also susceptible to NIBV challenge on the basis of virus isolation from trachea and kidney butshowed protection on the basis of renal microscopic pathology and IHC. Live IBV-primed chickens vaccinated with an autogenous inactivated PA/Wolgemuth/98 vaccine had the highest protection against homologous virulent NIBV challenge on the basis of virus isolation.

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PubMedDate not supplied

Identification of avian infectious bronchitis virus by direct automated cycle sequencing of the S-1 gene.

Direct automated cycle sequencing (DACS) of a reverse transcription-polymerase chain reaction (RT-PCR) product of the S-1 subunit of the spike peplomer gene was used to identify infectious bronchitis virus (IBV) serotypes. Degenerate primers CK4 and CK2, utilized previously in our laboratory, were selected for DACS because they successfully amplify a wide range of serotypes represented by various reference strains and field isolates and the resulting polymerase chain reaction (PCR) product contains diagnostically relevant S-1 sequences that can be used to identify the serotype of IBV. The S-1 nucleotide sequences generated by DACS were aligned and analyzed with commercial software to determine their relationship to the S-1 nucleotide sequences of IBV strains on deposit in the GenBank and EMBL databases. Reference strains Massachusetts (Mass) 41, Connecticut (Conn), Arkansas (Ark) DPI, JMK, and DE/072/92 were initially tested by DACS to establish the feasibility of the procedure. The DACS procedure was further evaluated with a panel of "unknowns" comprised of IBV reference strains, field isolates, and variant serotypes collected by our laboratory. The DACS procedure provided high-quality and reproducible S-1 sequence for all IBV serotypes tested, including variant serotypes that had not been sequenced previously. The S-1 nucleotide sequences for the amplified PCR products of reference strains Mass 41, Conn, Ark DPI, JMK, and DE/072/92 generated by DACS were highly homologous (>99% nucleotide identity) with their respective GenBank database sequences. In the unknown panel, the nucleotide identities of the DACS S-1 sequences of field isolates of serotypes previously identified by virus neutralization were also found to be very high (> or = 95.5%) after alignment with database sequences. In contrast, the nucleotide identities of S-1 sequences of variant serotypes 37, 3330, and PA/1220/98 and reference strain Clark 333, for which database sequences were not available, ranged from 27.7% to 73.8%, well below the identity values for a homologous serotype. With alignment software, the identities of strains in mixtures of RNAs of two different serotypes were not resolvable. DACS of IBV S-1 RT-PCR products will enable researchers to rapidly identify field strains, including new, previously unrecognized variant virus serotypes.

Amino Acid Sequence↗
PubMedDate not supplied

Emergence of subtype strains of the Arkansas serotype of infectious bronchitis virus in Delmarva broiler chickens.

Infectious bronchitis virus (IBV) field isolates of the Arkansas (Ark) serotype were identified by reverse transcription-polymerase chain reaction (RT-PCR) as the most common serotype isolated from 1993 to 1997. These isolates were recovered from broiler flocks with respiratory disease raised on the Delmarva peninsula in spite of Ark vaccination in the region. For the purposes of investigating this apparently paradoxical finding, five RT-PCR Ark-positive field isolates recovered in 1995 and 1996 were selected for further characterization. The isolates were compared with Ark reference strains by reciprocal virus neutralization (VN) in embryonated eggs, S-1 gene sequence analysis, and challenge of immunity studies in specific-pathogen-free (SPF) chickens. Antigenic (VN) comparisons and S-1 gene analysis confirmed that the five RT-PCR Ark-positive field isolates were of the Ark serotype but also revealed that the viruses could be readily distinguished from Ark reference strains. Four of the isolates (Ark/213/96, Ark/15C/96, Ark/1529/95, Ark/1534/95) were found to have higher antigenic relatedness percentages to each other (95%-100%) than to Ark reference strains DPI (52%-72%) and Georgia variant (Georgia var) (53%-68%) by VN. Another isolate, Ark/1535/95, was found to differ antigenically from the other four RT-PCR Ark-positive field isolates (34%-61%), Ark DPI (44%), and Georgia var (43%) strains. The trends in the S-1 gene sequencing results were similar to those observed for the VN findings. Isolates Ark/213/96, Ark/15C/96, Ark/1529/95, and Ark/1534/95 demonstrated a higher degree of predicted S-1 amino acid similarity to each other (96.5%-98.7%) than to Ark DPI (92.4%-93.7%), Ark 99 (93.2%-94.7%), and Georgia var (89.3%-90.8%). Ark/1535/95 S-1 amino acid similarity values were lower compared with those of the other four RT-PCR Ark-positive field isolates (93.4%-94.8%), Ark DPI (91.9%), Ark 99 (93.0%), and Georgia var (88.7%). Furthermore, the isolates could be distinguished from the Ark reference strains by a characteristic sequence polymorphism, a six-nucleotide deletion encoding amino acids 57 (Asp) and 58 (Asp) in hypervariable region 1 of S-1. On the basis of the VN and sequencing findings, isolates Ark/213/96, Ark/15C/96, Ark/1529/95, and Ark/1534/95 were considered to be a single subtype of the Ark serotype. The fifth isolate, Ark/1535/95, may constitute another subtype of the Ark serotype. Vaccination of SPF chickens with a high-titering commercially available live vaccine containing the Ark DPI strain provided solid protection (>90%) against challenge with the RT-PCR Ark-positive field isolates. Immunization of SPF chickens with Ark/213/96 produced 100% protection against challenge with the homologous strain, as well as isolates Ark/1535/95 and Ark 99 but lower levels of protection against Ark DPI (58%) and Georgia var (55%). Primers for RT-PCR were designed to distinguish between the Ark subtypes and the Ark reference strains on the basis of the characteristic six-nucleotide deletion identified in the S-1 gene of the Ark subtypes. Retrospective analysis of RT-PCR Ark-positive isolates found that the Ark subtypes existed as early as 1992 in Delmarva broilers and became prevalent by 1995. With RT-PCR, restriction fragment length polymorphism analysis, and DNA sequencing techniques, the presence of Ark subtype viruses was demonstrated in two commercial Ark DPI strain vaccines and in our Ark DPI laboratory stocks that were the original source of the virus used for vaccine development. The demonstration of the Ark subtype and reference strains in the Ark DPI strain is evidence of the existence of IBV quasispecies. Factors possibly influencing the emergence of the Ark subtype in commercial broilers are discussed.

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PubMedDate not supplied

Novel infectious bronchitis virus S1 genotypes in Mexico 1998-1999.

Seventeen infectious bronchitis virus (IBV) field isolates recovered from commercial broiler flocks in Mexico were identified by reverse transcription-polymerase chain reaction cycle sequencing of the S1 gene. The isolates were obtained from broilers on farms from the neighboring states of Queretaro and San Luis Potosi in 1998 and 1999. Flocks had an ongoing history of bacterial-complicated respiratory disease with mortality rates as high as 28% in spite of receiving live vaccinations for Massachusetts and Connecticut strains of IBV. Sequence analysis of the S1 gene identified two unique genotypes that have been described, as of this time, only in Mexico and thus appear to represent strains indigenous to the country. The Mex/1765/99 genotype was isolated from 64% (11/17) of the respiratory disease outbreaks. Three isolates (18%) were similar to the BL-56 genotype, a unique Mexican IBV strain observed initially in 1996. In addition to the two indigenous strains, three isolates (18%) were found to be the Connecticut genotype.

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PubMedDate not supplied

Production and characterization of monoclonal antibodies to three infectious bronchitis virus serotypes.

Three panels of monoclonal antibodies (MAbs) were prepared against the spike (S) proteins of infectious bronchitis virus (IBV) strains Arkansas 99, Connecticut 46, and Massachusetts 41. Based on enzyme-linked immunosorbent assay (ELISA), the MAbs were grouped into three categories: 1) group-specific, which reacted with a broad spectrum of homologous and heterologous IBV serotypes; 2) serotype-specific, which reacted only with strains of the homologous serotype; and 3) strain-specific, which reacted "selectively" with only certain strains of homologous and heterologous serotypes. MAbs that displayed serotype specificity were all specific to S1 fractions of the homologous serotype, confirming that epitopes that determine virus serotype are associated with the S1 protein. An excellent correlation was found when the results of IBV serotyping by MAb-based indirect ELISA were compared with those from the conventional virus-neutralization test. This confirms that the MAbs described here will serve as valuable tools in epizootiological studies and serotype-specific diagnosis of IBV infection.

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PubMedDate not supplied

Protection of chickens from Newcastle and Marek's diseases with a recombinant herpesvirus of turkeys vaccine expressing the Newcastle disease virus fusion protein.

Recombinant strains of herpesvirus of turkeys (HVT) were constructed that contain either the fusion protein gene or the hemagglutinin-neuraminidase gene of Newcastle disease virus (NDV) inserted into a nonessential gene of HVT. Expression of the NDV antigens was regulated from a strong promoter element derived from the Rous sarcoma virus long terminal repeat. Recombinant HVT strains were stable and fully infectious in cell culture and in chickens. Chickens receiving a single intra-abdominal inoculation at 1 day of age with recombinant HVT expressing the NDV fusion protein had an immunological response and were protected (> 90%) against lethal intramuscular challenge at 28 days of age with the neurotropic velogenic NDV strain Texas GB. Recombinant HVT expressing the NDV hemagglutinin-neuraminidase provided partial protection (47%) against the same challenge. Chickens vaccinated with recombinant HVT vaccines had low levels of protection against NDV replication in the trachea when challenged ocularly. Recombinant HVT vaccines and the parent HVT strain provided similar levels of protection to chickens challenged with the very virulent RB1B strain of Marek's disease virus, indicating that insertion of foreign sequences into the HVT genome did not compromise the ability of HVT to protect against Marek's disease.

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PubMedDate not supplied

Viral pathogenesis of a nephrotropic infectious bronchitis virus isolated from commercial pullets.

Infectious bronchitis was diagnosed in 3-to-4-week-old pullets from an outbreak in a commercial flock in California. The disease was characterized by head swelling, watery discharge from the eyes and nostrils, and urates in kidneys. Mortality ranged from 1.8% to 12.5% per week. The isolation of a coronavirus from a suspension of pooled kidneys from clinically ill chickens at the fifth passage in 10-day-old chicken embryos, gross and histologic renal lesions, and seroconversion by enzyme-linked immunosorbent assay in inoculated birds suggested that the virus isolated was a nephrotrophic strain of infectious bronchitis virus (IBV). The virus isolate was found to be a previously unrecognized serotype, based on virus neutralization tests performed in embryonated chicken eggs. Nephropathogenicity of the IBV isolate was confirmed by inoculation of the viral isolate into specific-pathogen-free chicks and demonstration of renal lesions. The isolation of nephrotropic strains of IBV has not been reported previously from poultry in California.

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PubMedDate not supplied

Attenuation of avian infectious bronchitis virus by cold-adaptation.

Avian infectious bronchitis virus (IBV) Arkansas-type DPI strain was passaged 10 times in specific-pathogen-free (SPF) chicken embryos incubated at 28 C and 37 C. Virus grown at 28 C acquired cold-adapted (CA) and temperature-sensitive (TS) characteristics based on more-rapid growth at 28 C and a reduced ability to grown at 41 C, respectively, compared with non-cold-adapted (non-CA) virus grown at 37 C. The pathogenicity and immunogenicity were determined for CA and non-CA IBV in 1-day-old SPF chickens following intratracheal inoculation. The percentage of CA IBV-vaccinated chicks exhibiting respiratory disease exceeded 30% on only 1 day postinoculation (PI) (day 5 PI), compared with 8 days (days 2-9 PI) for birds given non-CA IBV. Mortality was 0% for CA IBV-vaccinated chickens and 6% for non-CA virus-vaccinated chickens. Microscopically, both CA and non-CA IBV caused diffuse tracheal deciliation, although mucosal hyperplasia, necrosis, and heterophil infiltration were more severe with non-CA IBV. Virus was reisolated from kidneys of chickens given CA IBV, suggesting the loss of the TS property. The instability of the TS property was confirmed by growth of the reisolated virus at 41 C. Both CA and non-CA viruses induced complete protection against homologous challenge virus infection of the upper respiratory tract.

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