Biology subjects

Rivera-Hernandez, T.

Publications and source records attributed to Rivera-Hernandez, T..

3 recordsLinked to original sources

bioRxiv2024

Newcastle Disease Virus Vector-Based SARS-CoV-2 Vaccine Candidate AVX/COVID-12 Activates T Cells and Is Recognized by Antibodies from COVID-19 Patients and Vaccinated

Several effective vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed and implemented in the population. However, the current production capacity falls short of meeting global demand. Therefore, it is crucial to further develop novel vaccine platforms that can bridge the distribution gap. AVX/COVID-12 is a vector-based vaccine that utilizes the Newcastle Disease virus (NDV) to present the SARS-CoV-2 spike protein to the immune system. This study analyses the antigenicity of the vaccine candidate by examining antibody binding and T-cell activation in individuals infected with SARS-CoV-2 or variants of concern (VOCs), as well as in healthy volunteers who received coronavirus disease 2019 (COVID-19) vaccinations. Our findings indicate that the vaccine effectively binds antibodies and activates T-cells in individuals who received 2 or 3 doses of BNT162b2 or AZ/ChAdOx-1-S vaccines. Furthermore, the stimulation of T-cells from patients and vaccine recipients with AVX/COVID-12 resulted in their proliferation and secretion of interferon-gamma (IFN-{gamma}) in both CD4+ and CD8+ T-cells. In conclusion, the AVX/COVID-12 vectored vaccine candidate demonstrates the ability to stimulate robust cellular responses and is recognized by antibodies primed by the spike protein present in SARS-CoV-2 viruses that infected patients, as well as in the mRNA BNT162b2 and AZ/ChAdOx-1-S vaccines. These results support the inclusion of the AVX/COVID-12 vaccine as a booster in vaccination programs aimed at addressing COVID-19 caused by SARS-CoV-2 and its VOCs.

immunology↗

bioRxiv2020

Bioinformatic analysis of shared B and T cell epitopes amongst relevant coronaviruses to human health: Is there cross-protection?

Within the last 30 years 3 coronaviruses, SARS-CoV, MERS-CoV and SARS-CoV-2, have evolved and adapted to cause disease and spread amongst the human population. From the three, SARS-CoV-2 has spread world-wide and to July 2020 it has been responsible for more than 11 million confirmed cases and over half a million deaths. In the absence of an effective treatment or vaccine, social distancing has been the most effective measure to control the pandemic. However it has become evident that as the virus spreads the only tool that will allow us to fully control it is an effective vaccine. There are currently more than 150 vaccine candidates in different stages of development using a variety of viral antigens, with the S protein being the most targeted antigen. Although some new experimental evidence suggests cross-reacting responses between coronaviruses are present in the population, it remains unknown whether potential shared antigens between different coronaviruses could provide cross-protection. Given that coronaviruses are emerging pathogens and continue to represent a threat to global health, the development of a SARS-Cov-2 vaccine that could provide universal protection against other coronaviruses should be pushed forward. Here we present a thorough review of reported B and T cell epitopes shared between SARS-CoV-2 and other relevant coronaviruses, in addition we used web-based tools to predict novel B and T cell epitopes that have not been reported before. Analysis of experimental evidence that is constantly emerging complemented with the findings of this study allow us support the hypothesis that cross-reactive responses, particularly those coming from T cells, might play a key role in controlling infection by SARS-CoV-2. We hope that with the evidence presented in this manuscript we provide arguments to encourage the study of cross-reactive responses in order to elucidate their role in immunity to SARS-CoV-2. Finally we expect our findings will aid targeted analysis of antigen-specific immune responses and guide future vaccine design aiming to develop a cross reactive effective vaccine against respiratory diseases caused by coronaviruses.

immunology↗

bioRxiv2020

Prophage exotoxins enhance colonization fitness in epidemic scarlet fever-causing Streptococcus pyogenes

The re-emergence of scarlet fever poses a new global public health threat. The capacity of North-East Asian serotype M12 (emm12) Streptococcus pyogenes (group A Streptococcus, GAS) to cause scarlet fever has been linked epidemiologically to the presence of novel prophages, including prophage {Phi}HKU.vir encoding the secreted superantigens SSA and SpeC and the DNase Spd1. Here we report the comprehensive molecular characterization of {Phi}HKU.vir-encoded exotoxins. We demonstrate that streptolysin O (SLO)-induced glutathione efflux from host cellular stores is a previously unappreciated GAS virulence mechanism that promotes SSA release and activity, representing the first description of a thiol-activated bacterial superantigen. Spd1 is required for optimal growth in human blood, confers resistance to neutrophil killing, and degrades neutrophil extracellular traps (NETs). Investigating single, double and triple isogenic knockout mutants of the {Phi}HKU.vir-encoded exotoxins, we find that SpeC and Spd1 act synergistically to facilitate nasopharyngeal colonization in a mouse model. These results offer insight into the etiology and pathogenesis of scarlet fever-causing GAS mediated by phage {Phi}HKU.vir exotoxins.

microbiology↗