FluB-RAM and FluB-RANS: Genome Rearrangement as Safe and Efficacious Live Attenuated Influenza B Virus Vaccines

Influenza B virus (IBV) is considered a major respiratory pathogen responsible for seasonal respiratory disease in humans, particularly severe in children and the elderly. Seasonal influenza vaccination is considered the most efficient strategy to prevent and control IBV infections. Live attenuated influenza virus vaccines (LAIVs) are thought to induce both humoral and cellular immune responses by mimicking a natural infection, but their effectiveness has recently come into question. Thus, the opportunity exists to find alternative approaches to improve overall influenza vaccine effectiveness. Two alternative IBV backbones were developed with rearranged genomes, rearranged M (FluB-RAM) and a rearranged NS (FluB-RANS). Both rearranged viruses showed temperature sensitivity in vitro compared with the WT type B/Bris strain, were genetically stable over multiple passages in embryonated chicken eggs and were attenuated in vivo in mice. In a prime-boost regime in naïve mice, both rearranged viruses induced antibodies against HA with hemagglutination inhibition titers considered of protective value. In addition, antibodies against NA and NP were readily detected with potential protective value. Upon lethal IBV challenge, mice previously vaccinated with either FluB-RAM or FluB-RANS were completely protected against clinical disease and mortality. In conclusion, genome re-arrangement renders efficacious LAIV candidates to protect mice against IBV

FluB-RAM and FluB-RANS: Genome Rearrangement as Safe and Efficacious Live Attenuated Influenza B Virus Vaccines

Influenza B virus (IBV) is considered a major respiratory pathogen responsible for seasonal respiratory disease in humans, particularly severe in children and the elderly. Seasonal influenza vaccination is considered the most efficient strategy to prevent and control IBV infections. Live attenuated influenza virus vaccines (LAIVs) are thought to induce both humoral and cellular immune responses by mimicking a natural infection, but their effectiveness has recently come into question. Thus, the opportunity exists to find alternative approaches to improve overall influenza vaccine effectiveness. Two alternative IBV backbones were developed with rearranged genomes, rearranged M (FluB-RAM) and a rearranged NS (FluB-RANS). Both rearranged viruses showed temperature sensitivity in vitro compared with the WT type B/Bris strain, were genetically stable over multiple passages in embryonated chicken eggs and were attenuated in vivo in mice. In a prime-boost regime in naïve mice, both rearranged viruses induced antibodies against HA with hemagglutination inhibition titers considered of protective value. In addition, antibodies against NA and NP were readily detected with potential protective value. Upon lethal IBV challenge, mice previously vaccinated with either FluB-RAM or FluB-RANS were completely protected against clinical disease and mortality. In conclusion, genome re-arrangement renders efficacious LAIV candidates to protect mice against IBV

Additional file 1: Table S1. of Expression of chicken interleukin-2 by a highly virulent strain of Newcastle disease virus leads to decreased systemic viral load but does not significantly affect mortality in chickens

Summary of clinical signs and mortality in 4-week-old chickens infected with rZJ1-GFP, rZJ1-IL2, and BHI. Numbers in the cells represent the percentages of birds presenting the clinical sign over the total birds present in the group at the time. Highlighted cells represent groups where all the animals are dead. (XLSX 13 kb

Effects of Chicken Interferon Gamma on Newcastle Disease Virus Vaccine Immunogenicity.

More effective vaccines are needed to control avian diseases. The use of chicken interferon gamma (chIFNγ) during vaccination is a potentially important but controversial approach that may improve the immune response to antigens. In the present study, three different systems to co-deliver chIFNγ with Newcastle disease virus (NDV) antigens were evaluated for their ability to enhance the avian immune response and their protective capacity upon challenge with virulent NDV. These systems consisted of: 1) a DNA vaccine expressing the Newcastle disease virus fusion (F) protein co-administered with a vector expressing the chIFNγ gene for in ovo and booster vaccination, 2) a recombinant Newcastle disease virus expressing the chIFNγ gene (rZJ1*L/IFNγ) used as a live vaccine delivered in ovo and into juvenile chickens, and 3) the same rZJ1*L/IFNγ virus used as an inactivated vaccine for juvenile chickens. Co-administration of chIFNγ with a DNA vaccine expressing the F protein resulted in higher levels of morbidity and mortality, and higher amounts of virulent virus shed after challenge when compared to the group that did not receive chIFNγ. The live vaccine system co-delivering chIFNγ did not enhanced post-vaccination antibody response, nor improved survival after hatch, when administered in ovo, and did not affect survival after challenge when administered to juvenile chickens. The low dose of the inactivated vaccine co-delivering active chIFNγ induced lower antibody titers than the groups that did not receive the cytokine. The high dose of this vaccine did not increase the antibody titers or antigen-specific memory response, and did not reduce the amount of challenge virus shed or mortality after challenge. In summary, regardless of the delivery system, chIFNγ, when administered simultaneously with the vaccine antigen, did not enhance Newcastle disease virus vaccine immunogenicity

Development of a Novel Live Attenuated Influenza A Virus Vaccine Encoding the IgA-Inducing Protein

Live attenuated influenza virus (LAIV) vaccines elicit a combination of systemic and mucosal immunity by mimicking a natural infection. To further enhance protective mucosal responses, we incorporated the gene encoding the IgA-inducing protein (IGIP) into the LAIV genomes of the cold-adapted A/Leningrad/134/17/57 (H2N2) strain (caLen) and the experimental attenuated backbone A/turkey/Ohio/313053/04 (H3N2) (OH/04att). Incorporation of IGIP into the caLen background led to a virus that grew poorly in prototypical substrates. In contrast, IGIP in the OH/04att background (IGIP-H1att) virus grew to titers comparable to the isogenic backbone H1att (H1N1) without IGIP. IGIP-H1att- and H1caLen-vaccinated mice were protected against lethal challenge with a homologous virus. The IGIP-H1att vaccine generated robust serum HAI responses in naïve mice against the homologous virus, equal or better than those obtained with the H1caLen vaccine. Analyses of IgG and IgA responses using a protein microarray revealed qualitative differences in humoral and mucosal responses between vaccine groups. Overall, serum and bronchoalveolar lavage samples from the IGIP-H1att group showed trends towards increased stimulation of IgG and IgA responses compared to H1caLen samples. In summary, the introduction of genes encoding immunomodulatory functions into a candidate LAIV can serve as natural adjuvants to improve overall vaccine safety and efficacy

Characterization and evaluation of the effect of co-delivering chIFNγ with a DNA vaccination system.

<p>Plasmids expressing NDV F and chIFNγ genes were developed and characterized for their use as DNA vaccines and adjuvant, respectively. DF-1 cells were transfected with pTriEX, pTriEX-ZJ1-F and pTriEX- IFNγ. Cell culture supernatants were tested by western blotting for the presence of F protein <b>(A)</b> and chIFNγ <b>(B)</b>, respectively. Eighteen-day-old SPF ECEs were inoculated with TE buffer, pTriEX, pTriEX-ZJ1-F, or pTriEX-ZJ1-F plus pTriEX- IFNγ and boosted 2 weeks after hatched. Two weeks after booster vaccination, birds were challenged with vZJ1. Oropharyngeal <b>(C)</b> and cloacal <b>(D)</b> swab samples were collected 3 days after challenge to measure the amount of challenge virus shed into the environment. Viral titers were determined by quantitative real time reverse transcription polymerase chain reaction (qRRT-PCR). A standard was prepared with a vZJ1 virus stock of know concentration, this was included in every plate and was used to obtain viral titers expressed as EID₅₀/mL. Morbidity <b>(E)</b> and mortality <b>(F)</b> were also evaluated. Viral shedding results were analyzed with One-way ANOVA followed by a multiple comparisons Tukey's test. Differences in morbidity among groups were evaluated using a two-tailed Z test for comparison of sample proportions. Survival curves were analyzed using the Long-Rank test. Statistical difference was considered with a <i>P<0</i>.<i>05</i>. Significant differences are denoted by different letters.</p

Effect of chIFNγ on hatchability and survival after <i>in ovo</i> vaccination with rZJ1*L/IFNγ and challenge with vZJ1.

<p>Effect of chIFNγ on hatchability and survival after <i>in ovo</i> vaccination with rZJ1*L/IFNγ and challenge with vZJ1.</p