RESUMO
Chlorogenic acid (CGA) is a phenolic compound that has been well studied for its antiviral, anti-inflammatory and immune stimulating properties. This research was aimed to focus on the antiviral properties of CGA on infectious bronchitis virus (IBV) in vivo and in vitro for the very first time. The outcome of in vitro experiments validated that, out of five previously reported antiviral components, CGA significantly reduced the relative mRNA expression of IBV-N in CEK cells. At high concentration (400 mg/kg), CGA supplementation reduced IBV-N mRNA expression levels and ameliorated the injury in trachea and lungs. The mRNA expression levels of IL-6, IL-1ß, IL-12, and NF-κB were considerably turned down, but IL-22 and IL-10 were enhanced in trachea. However, CGA-H treatment had considerably increased the expression levels of MDA5, MAVS, TLR7, MyD88, IRF7, IFN-ß and IFN-α both in trachea and lungs. Moreover, CGA-H notably induced the CD3+, CD3+ CD4+ and CD4+/CD8+ proliferation and significantly increased the IgA, IgG, and IgM levels in the serum. In conclusion, these results showed that at high concentration CGA is a strong anti-IBV compound that can effectively regulate the innate immunity through MDA5, TLR7 and NF-κB signaling pathways and have the potential to induce the cell mediated and humoral immune response in IBV infected chickens.
Assuntos
Ácido Clorogênico/farmacologia , Infecções por Coronavirus/tratamento farmacológico , Gammacoronavirus/efeitos dos fármacos , Helicase IFIH1 Induzida por Interferon/metabolismo , NF-kappa B/metabolismo , Receptor 7 Toll-Like/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Antivirais/farmacologia , Células Cultivadas , Galinhas , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Modelos Animais de Doenças , Gammacoronavirus/imunologia , Gammacoronavirus/isolamento & purificação , Imunidade Inata , Helicase IFIH1 Induzida por Interferon/genética , NF-kappa B/genética , Receptor 7 Toll-Like/genéticaRESUMO
The Gammacoronavirus infectious bronchitis virus (IBV) causes a highly contagious and economically important respiratory disease in poultry. In the laboratory, most IBV strains are restricted to replication in ex vivo organ cultures or in ovo and do not replicate in cell culture, making the study of their basic virology difficult. Entry of IBV into cells is facilitated by the large glycoprotein on the surface of the virion, the spike (S) protein, comprised of S1 and S2 subunits. Previous research showed that the S2' cleavage site is responsible for the extended tropism of the IBV Beaudette strain. This study aims to investigate whether protease treatment can extend the tropism of other IBV strains. Here we demonstrate that the addition of exogenous trypsin during IBV propagation in cell culture results in significantly increased viral titres. Using a panel of IBV strains, exhibiting varied tropisms, the effects of spike cleavage on entry and replication were assessed by serial passage cell culture in the presence of trypsin. Replication could be maintained over serial passages, indicating that the addition of exogenous protease is sufficient to overcome the barrier to infection. Mutations were identified in both S1 and S2 subunits following serial passage in cell culture. This work provides a proof of concept that exogenous proteases can remove the barrier to IBV replication in otherwise non-permissive cells, providing a platform for further study of elusive field strains and enabling sustainable vaccine production in vitro.
Assuntos
Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Vírus da Bronquite Infecciosa/efeitos dos fármacos , Vírus da Bronquite Infecciosa/fisiologia , Tripsina/uso terapêutico , Tropismo Viral/efeitos dos fármacos , Animais , Linhagem Celular , Chlorocebus aethiops , Gammacoronavirus/efeitos dos fármacos , Vírus da Bronquite Infecciosa/metabolismo , Cinética , Inoculações Seriadas , Glicoproteína da Espícula de Coronavírus/metabolismo , Células Vero , Proteínas do Envelope Viral/metabolismo , Vírion/efeitos dos fármacos , Vírion/metabolismo , Replicação Viral/efeitos dos fármacosRESUMO
The COVID-19 infection, caused by SARS-CoV-2, is inequitably distributed and more lethal among populations with lower socioeconomic status. Direct contact with contaminated surfaces has been among the virus sources, as it remains infective up to days. Several disinfectants have been shown to inactivate SARS-CoV-2, but they rapidly evaporate, are flammable or toxic and may be scarce or inexistent for vulnerable populations. Therefore, we are proposing simple, easy to prepare, low-cost and efficient antiviral films, made with a widely available dishwashing detergent, which can be spread on hands and inanimate surfaces and is expected to maintain virucidal activity for longer periods than the current sanitizers. Avian coronavirus (ACoV) was used as model of the challenge to test the antivirus efficacy of the proposed films. Polystyrene petri dishes were covered with a thin layer of detergent formula. After drying, the films were exposed to different virus doses for 10 min and virus infectivity was determined using embryonated chicken eggs, and RNA virus quantification in allantoic fluids by RT-qPCR. The films inactivated the ACoV (ranging from 103.7 to 106.7 EID50), which is chemically and morphologically similar to SARS-CoV-2, and may constitute an excellent alternative to minimize the spread of COVID-19.