Biology subjects

Martini, V.

Publications and source records attributed to Martini, V..

8 recordsLinked to original sources

bioRxiv2021

Spatial, temporal and molecular dynamics of swine influenza virus-specific CD8 tissue resident memory T cells.

We defined naive, central memory, effector memory and terminally differentiated porcine CD8 T cells and analyzed their phenotype in lymphoid and respiratory tissues after influenza infection or immunization using peptide-MHC tetramers of three influenza nucleoprotein (NP) epitopes. The hierarchy of response to the three epitopes changes during the response in different tissues. Most NP-specific CD8 T cells in broncho-alveolar lavage (BAL) and lung are tissue resident memory cells (TRM), that express CD69 and have an effector memory or terminally differentiated phenotype. NP-specific cells isolated from BAL express genes characteristic of TRM, but gene expression differs at 7, 21 and 63 days post infection. The frequency of NP-specific cells declines over 63 days in all tissues but is best maintained in BAL. The pig is a powerful model for understanding how best to induce and harness local immunity to respiratory viruses. One sentence summaryInfluenza NP-specific porcine tissue resident memory CD8 T cells persist in the lung with major changes in gene expression.

immunology↗

bioRxiv2021

Simultaneous infection with porcine reproductive and respiratory syndrome and influenza viruses abrogates clinical protection induced by live attenuated porcine reproductive and respiratory syndrome vaccination

The porcine respiratory disease complex (PRDC) is responsible for significant economic losses in the pig industry worldwide. Porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus are major viral contributors to PRDC. Vaccines are cost-effective measures for controlling PRRS, however, their efficacy in the context of co-infections has been poorly investigated. In this study, we aimed to determine the effect of PRRSV-2 and swine influenza H3N2 virus co-infection on the efficacy of PRRSV modified live virus (MLV) vaccination, which is widely used in the field. Following simultaneous challenge with contemporary PRRSV-2 and H3N2 field isolates, we found that the protective effect of PRRS MLV vaccination on clinical disease and pathology was abrogated, although viral load was unaffected and antibody responses were enhanced. In contrast, co-infection in non-immunized animals reduced PRRSV-2 viremia and H3N2 virus load in the upper respiratory tract and potentiated T cell responses against both PRRSV-2 and H3N2 in the lung. Further analysis suggested that an upregulation of inhibitory cytokines gene expression in the lungs of vaccinated pigs may have influenced responses to H3N2 and PRRSV-2. These findings provide important insights into the effect of viral co-infections on PRRS vaccine efficacy that may help identity more effective vaccination strategies against PRDC in the field.

immunology↗

bioRxiv2020

Magnitude and kinetics of T cell and antibody responses during H1N1pdm09 infection in outbred and inbred Babraham pigs

We have used the pig, a large natural host animal for influenza with many physiological similarities to humans, to characterize {beta}, {gamma}{delta} T cell and antibody (Ab) immune responses to the 2009 pandemic H1N1 virus infection. We evaluated the kinetic of virus infection and associated response in inbred Babraham pigs with identical MHC (Swine Leucocyte Antigen) and compared them to commercial outbred animals. High level of nasal virus shedding continued up to day 4-5 post infection followed by a steep decline and clearance of virus by day 9. Adaptive T cell and Ab responses were detectable from day 5-6 post infection reaching a peak at 9-14 days. {gamma}{delta} cells produced cytokines ex vivo at day 2 post infection, while virus specific IFN{gamma} producing {gamma}{delta} T cells were detected from day 7 post infection. Analysis of NP tetramer specific and virus specific CD8 and CD4 T cells in blood, lung, lung draining lymph nodes and broncho-alveolar lavage (BAL) showed clear differences in cytokine production between these tissues. BAL contained the most highly activated CD8, CD4 and {gamma}{delta} cells producing large amounts of cytokines, which likely contribute to elimination of virus. The weak response in blood did not reflect the powerful local lung immune responses. The immune response in the Babraham pig following H1N1pdm09 influenza infection was comparable to that of outbred animals. The ability to utilize these two swine models together will provide unparalleled power to analyse immune responses to influenza.

immunology↗

bioRxiv2020

Simultaneous aerosol and intra-muscular immunization with influenza vaccine induces powerful protective local T cell and systemic Ab immune responses in pigs

A vaccine providing both powerful antibody and cross-reactive T cell immune responses against influenza viruses would be beneficial for both humans and pigs. Here we evaluated intramuscular (IM), aerosol (Aer) and simultaneous immunization (SIM) by both routes in pigs, using the single cycle candidate influenza vaccine S-FLU. After prime and boost immunization pigs were challenged with H1N1pdm09 virus. IM immunized pigs generated high titer of neutralizing antibodies but poor T cell responses, while Aer induced powerful respiratory tract T cell responses, but a low titer of antibodies. SIM pigs combined high antibody titers and strong local T cell responses. SIM pigs showed the most complete suppression of virus shedding and the greatest improvement in pathology. We conclude that SIM regimes for immunization against respiratory pathogens warrant further study.

immunology↗

bioRxiv2020

A COVID-19 vaccine candidate using SpyCatcher multimerization of the SARS-CoV-2 spike protein receptor-binding domain induces potent neutralising antibody responses

There is dire need for an effective and affordable vaccine against SARS-CoV-2 to tackle the ongoing pandemic. In this study, we describe a modular virus-like particle vaccine candidate displaying the SARS-CoV-2 spike glycoprotein receptor-binding domain (RBD) using SpyTag/SpyCatcher technology (RBD-SpyVLP). Low doses of RBD-SpyVLP in a prime-boost regimen induced a strong neutralising antibody response in mice and pigs that was superior to convalescent human sera. We evaluated antibody quality using ACE2 blocking and neutralisation of cell infection by pseudovirus or wild-type SARS-CoV-2. Using competition assays with a monoclonal antibody panel, we showed that RBD-SpyVLP induced a polyclonal antibody response that recognised all key epitopes on the RBD, reducing the likelihood of selecting neutralisation-escape mutants. The induction of potent and polyclonal antibody responses by RBD-SpyVLP provides strong potential to address clinical and logistic challenges of the COVID-19 pandemic. Moreover, RBD-SpyVLP is highly resilient, thermostable and can be lyophilised without losing immunogenicity, to facilitate global distribution and reduce cold-chain dependence.

immunology↗

bioRxiv2020

Evaluation of the immunogenicity of prime-boost vaccination with the replication-deficient viral vectored COVID-19 vaccine candidate ChAdOx1 nCoV-19

Clinical development of the COVID-19 vaccine candidate ChAdOx1 nCoV-19, a replication-deficient simian adenoviral vector expressing the full-length SARS-CoV-2 spike (S) protein was initiated in April 2020 following non-human primate studies using a single immunisation. Here, we compared the immunogenicity of one or two doses of ChAdOx1 nCoV-19 in both mice and pigs. Whilst a single dose induced antigen-specific antibody and T cells responses, a booster immunisation enhanced antibody responses, particularly in pigs, with a significant increase in SARS-CoV-2 neutralising titres.

immunology↗

bioRxiv2020

Distribution of droplets and immune responses after aerosol and intra-nasal delivery of influenza virus to the respiratory tract of pigs

Recent evidence indicates that local immune responses and tissue resident memory T cells (TRM) are critical for protection against respiratory infections but there is little information on the contributions of upper and lower respiratory tract (URT and LRT) immunity. To provide a rational basis for designing methods for optimal delivery of vaccines to the respiratory tract in a large animal model, we investigated the distribution of droplets generated by a mucosal atomization device (MAD) and two vibrating mesh nebulizers (VMNs) and the immune responses induced by delivery of influenza virus by MAD in pigs. We showed that droplets containing the drug albuterol, a radiolabel (99mTc-DTPA) or a model influenza virus vaccine (S-FLU) have similar aerosol characteristics. 99mTc-DTPA scintigraphy showed that VMNs deliver droplets with uniform distribution throughout the lungs as well as the URT. Surprisingly MAD administration (1ml/nostril) also delivered a high proportion of the dose to the lungs, albeit concentrated in a small area. After MAD administration of influenza virus, antigen specific T cells were found at high frequency in nasal turbinates, trachea, broncho-alveolar lavage, lungs, tracheobronchial nodes and blood. We conclude that the pig is useful for investigating optimal targeting of vaccines to the respiratory tract.

immunology↗

bioRxiv2020

Establishment of a pig influenza challenge model for evaluation of monoclonal antibody delivery platforms

Monoclonal antibodies are a possible adjunct to vaccination and drugs in treatment of influenza virus infection. However questions remain whether small animal models accurately predict efficacy in humans. We have established the pig, a large natural host animal for influenza, with many physiological similarities to humans, as a robust model for testing monoclonal antibodies. We show that a strongly neutralizing monoclonal antibody (2-12C) against the hemagglutinin head administered prophylactically at 15 mg/kg reduced viral load and lung pathology after pandemic H1N1 influenza challenge. A lower dose of 1 mg/kg of 2-12C or a DNA plasmid encoded version of 2-12C, reduced pathology and viral load in the lungs, but not viral shedding in nasal swabs. We propose that the pig influenza model will be useful for testing candidate monoclonal antibodies and emerging delivery platforms prior to human trials.

immunology↗