Avaliação in vitro da atividade antiviral de um peptídeo sintético derivado de veneno de escorpião contra o vírus respiratório sincicial (VRS), cepa A2

Abstract

Respiratory syncytial virus (RSV) is the main cause of acute respiratory infections (ARIs), especially in children under 5 years of age, responsible for several cases of hospitalizations and deaths each year, leading to severe economic losses. So far there is no vaccine approved for use against the pathogen. Thus, the research and development of peptides with antiviral activity (AVPs) derived from natural sources becomes an attractive option against the disease caused by RSV. The venom of different species of scorpions has been shown to be an interesting source for obtaining AVPs that can, after being identified, be punctually modified to improve pharmacological activity and decrease in adverse effects. Thereby, the present study determined the titration of RSV, strain A2, in human laryngeal carcinoma-derived tumor cell line (HEp-2); and evaluated the antiviral activity of a synthetic peptide derived from scorpion venom against the virus. For viral titration, serial dilutions (10-1 to 10-5) of the viral stock were prepared and the number of plaque forming units (PFU) per ml present in the sample. Subsequently, using the MTT assay, the antiviral activity of the peptide in different concentrations (400 μg / mL to 3.125 μg / mL) was investigated prior to viral infection (pretreatment assay) or after viral infection (post-treatment assay). From the analyzes, the RSV A2 strain titre, was determined in 2.7x107 PFU / mL and it was found that the evaluated peptide shows a tendency to antiviral activity against RSV infection, with values ranging from 0.23% (6.25 μg / mL) to 86.48% (25.0 μg / mL) in the pre-treatment assay and from 59.51% (50.0 μg / mL) to 125 , 88% (12.5 μg / mL) at post-treatment. In addition, it can be observed that the peptide has a greater ability to inhibit the final stages of the viral cycle than the adsorption and penetration steps. Therefore, the results obtained here are relevant because they demonstrate a peptide with potential antiviral activity, and that in the future it may have its activity evaluated against RSV infection in in vivo models. Subsequent assays will be performed to confirm the antiviral activity, ensuring greater accuracy in the results.