Genetic variability in G2 and F2 region between biological clones of human respiratory syncytial virus with or without host immune selection pressure

Abstract

Human respiratory syncytial virus (HRSV) is an important respiratory pathogens among children between zero-five years old. Host immunity and viral genetic variability are important factors that can make vaccine production difficult. In this work, differences between biological clones of HRSV were detected in clinical samples in the absence and presence of serum collected from children in the convalescent phase of the illness and from their biological mothers. Viral clones were selected by plaque assay in the absence and presence of serum and nucleotide sequences of the G2 and F2 genes of HRSV biological clones were compared. One non-synonymous mutation was found in the F gene (Ile5Asn) in one clone of an HRSV-B sample and one non-synonymous mutation was found in the G gene (Ser291Pro) in four clones of the same HRSV-B sample. Only one of these clones was obtained after treatment with the child's serum. In addition, some synonymous mutations were determined in two clones of the HRSV-A samples. In conclusion, it is possible that minor sequences could be selected by host antibodies contributing to the HRSV evolutionary process, hampering the development of an effective vaccine, since we verify the same codon alteration in absence and presence of human sera in individual clones of BR-85 sample.

Avaliação da susceptibilidade de mutantes de escape do vírus sincicial respiratório frente ao Palivizumab pelo método de microneutralização <i>in vitro</i>.

“…Isso faz com que o HRSV seja bastante adaptável às pressões seletivas e proporcionando assim o aparecimento de quasiespécies (Zhao et al, 2004). As quasiespécies naturais de vírus de RNA permitem a emergência rápida de vírus mutantes que escapam da pressão imune do hospedeiro frente a este monoclonal (Moraes et al, 2015). Trabalhos prévios demonstraram que mutações nos aminoácidos S268I, K272Q, K272E, S275L e N276S já existem na população e podem propiciar pacientes com recidivas (Zhu et al, 2011;Papenburg et al, 2012;Tomé et al, 2012;Oliveira et al, 2015).…”