Differential effect of maternal antibodies on efficacy of cellular and cell‐free Marek's disease vaccines

Witter, R. L.; Burmester, B. R.

doi:10.1080/03079457908418337

Cited by 71 publications

(22 citation statements)

References 21 publications

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“…Since the rHVT-H5 vaccine is cell-associated, inside the lymphocytes it provides a pathway which might stimulate cell-mediated immunity (King et al, 1981). In addition to the humoral response, this cell-associated immune response is thought to be insensitive to MDA interference (Witter & Burmester, 1979) and a persistent viraemia occurs during the first eight weeks of age with the HVT virus. In addition, due to the continuous expression of the antigen, rHVT vaccination induces long-lasting immunity (Reddy et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

Comparison of the effectiveness of rHVT-H5, inactivated H5 and rHVT-H5 with inactivated H5 prime/boost vaccination regimes in commercial broiler chickens carrying MDAs against HPAI H5N1 clade 2.2.1 virus

Kilany¹,

Hassan²,

Safwat³

et al. 2015

Avian Pathology

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(2015) Comparison of the effectiveness of rHVT-H5, inactivated H5 and rHVT-H5 with inactivated H5 prime/boost vaccination regimes in commercial broiler chickens carrying MDAs against HPAI H5N1 clade 2.2.1 virus, Avian Pathology, 44:5, 333-341, DOI: 10.1080/03079457.2015 Vaccination is the main tool implemented in Egypt since 2007 to control H5N1 avian influenza. The present study aimed at comparing the effectiveness of three avian influenza vaccination regimes in commercial broiler chickens carrying high levels of maternally derived antibodies (MDAs). Day-old chicks were divided into four experimental groups. Group I received only the rHVT-H5 vaccine (recombinant turkey herpesvirus (HVT) which carries a H5 clade 2.2 insert) administered at D1. Group II received only the KV-H5 (an oil emulsion killed vaccine prepared from reassortant HPAI virus (A/duck/Anhui/1/06)) vaccine (inactivated reverse genetic H5N1 clade 2.3.4 virus) administered at D8. Group III received rHVT-H5 and KV-H5 as prime/boost. Group IV served as unvaccinated control. Weekly serological monitoring was conducted using the haemagglutination inhibition test. Two challenge experiments were conducted at D28 and D35 using HPAI H5N1 clade 2.2.1 virus. Birds were monitored daily 14 days post-challenge for morbidity and mortality, and oropharyngeal swabs were collected for virological monitoring. Initially, day-old chicks had high mean MDA titres (9 + 0.9 log 2 ). The MDA half-life was >7 and <7 days, respectively, for unvaccinated and vaccinated birds. Group III showed the highest post-vaccination humoral immune response and seroconversion rate. The highest protection rate against morbidity (80-90%) and mortality (90-90%) was obtained in Group III after challenge at D28 and D35, respectively, as compared to Group I (70-70%) and (80-90%) and Group II (0-0%) and (30-30%). Groups I and III had lower number of shedder birds. The vaccination regime with prime/boost conferred the highest and earliest protection, and can hence be recommended for the broiler production sector in endemic and high HPAI H5N1 challenge areas.

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Section: Discussionmentioning

confidence: 99%

Comparison of the effectiveness of rHVT-H5, inactivated H5 and rHVT-H5 with inactivated H5 prime/boost vaccination regimes in commercial broiler chickens carrying MDAs against HPAI H5N1 clade 2.2.1 virus

Kilany¹,

Hassan²,

Safwat³

et al. 2015

Avian Pathology

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“…When cytopathic effects were visible in 100% of the cell monolayer, the infected cells were harvested, and virus titers were measured by plaque assay. 40 These infected CEFs were used as inoculum for experimental infection of chickens.…”

Section: Methodsmentioning

confidence: 99%

Development of a Nested Polymerase Chain Reaction Method to Detect Oncogenic Marek's Disease Virus from Feather Tips

et al. 2007

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Abstract. For the easy survey of Marek's disease virus (MDV), feather tip-derived DNA from MDVinfected chickens can be used because feather tips are easy to collect and feather follicle epithelium is known to be the only site of productive replication of cell-free MDV. To develop a diagnostic method to differentiate highly virulent strains of MDV from the attenuated MDV vaccine strain, CVI988, which is widely used, nested polymerase chain reaction (PCR) was performed to detect a segment of the meq gene in feather tip samples of chickens experimentally infected with MDV. In chickens infected with Md5, a strain of oncogenic MDV, the meq gene was consistently detected, whereas the L-meq gene, in which a 180-base pair (180-bp) sequence is inserted into the meq gene, was detected in CVI988-infected chickens. Moreover, the meq gene was mainly detected even in chickens co-infected with both Md5 and CVI988. These results suggest that this method is appropriate for the surveillance of the highly virulent MDV infection in the field.

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“…In all instances, virus shedding was also significantly reduced compared to sham-vaccinated [10]. The cell-associated form of HVT vaccine is considered more immunologically efficacious than the cell-free form especially in the presence of maternally derived antibodies [25]. Therefore, we tested both forms of rHVT-Hu4999 in this experiment because the cell-free form has an advantage in transportation and storage over the cell associated form, which requires liquid nitrogen.…”

Section: Discussionmentioning

confidence: 95%

Vaccine protection of chickens against antigenically diverse H5 highly pathogenic avian influenza isolates with a live HVT vector vaccine expressing the influenza hemagglutinin gene derived from a clade 2.2 avian influenza virus

Kapczynski

Esaki²,

Dorsey³

et al. 2015

Vaccine

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Vaccination is an important tool in the protection of poultry against avian influenza (AI). For field use, the overwhelming majority of AI vaccines produced are inactivated whole virus formulated into an oil emulsion. However, recombinant vectored vaccines are gaining use for their ability to induce protection against heterologous isolates and ability to overcome maternal antibody interference. In these studies, we compared protection of chickens provided by a turkey herpesvirus (HVT) vector vaccine expressing the hemagglutinin (HA) gene from a clade 2.2 H5N1 strain (A/swan/Hungary/4999/2006) against homologous H5N1 as well as heterologous H5N1 and H5N2 highly pathogenic (HP) AI challenge. The results demonstrated all vaccinated birds were protected from clinical signs of disease and mortality following homologous challenge. In addition, oral and cloacal swabs taken from challenged birds demonstrated that vaccinated birds had lower incidence and titers of viral shedding compared to sham-vaccinated birds. Following heterologous H5N1 or H5N2 HPAI challenge, 80-95% of birds receiving the HVT vector AI vaccine at day of age survived challenge with fewer birds shedding virus after challenge than sham vaccinated birds. In vitro cytotoxicity analysis demonstrated that splenic T lymphocytes from HVT-vector-AI vaccinated chickens recognized MHC-matched target cells infected with H5, as well as H6, H7, or H9 AI virus. Taken together, these studies provide support for the use of HVT vector vaccines expressing HA to protect poultry against multiple lineages of HPAI, and that both humoral and cellular immunity induced by live vaccines likely contributes to protection.

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Differential effect of maternal antibodies on efficacy of cellular and cell‐free Marek's disease vaccines

Cited by 71 publications

References 21 publications

Comparison of the effectiveness of rHVT-H5, inactivated H5 and rHVT-H5 with inactivated H5 prime/boost vaccination regimes in commercial broiler chickens carrying MDAs against HPAI H5N1 clade 2.2.1 virus

Comparison of the effectiveness of rHVT-H5, inactivated H5 and rHVT-H5 with inactivated H5 prime/boost vaccination regimes in commercial broiler chickens carrying MDAs against HPAI H5N1 clade 2.2.1 virus

Development of a Nested Polymerase Chain Reaction Method to Detect Oncogenic Marek's Disease Virus from Feather Tips

Vaccine protection of chickens against antigenically diverse H5 highly pathogenic avian influenza isolates with a live HVT vector vaccine expressing the influenza hemagglutinin gene derived from a clade 2.2 avian influenza virus

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