Respiratory syncytial virus and neutrophil activation

Abstract

SummaryRespiratory syncytial virus infects almost all children by 2 years of age. Neutrophils are the predominant airway leucocytes in RSV bronchiolitis and they are activated in the presence of infection. However it is not clear whether RSV can directly signal to activate neutrophil cytotoxic function. To investigate this we have used a preparation of RSV washed using a new centrifugal diafiltration method to rapidly remove inflammatory molecules produced by the epithelial cells used to propagate the RSV stock. Human neutrophils were isolated from peripheral blood and activated with either the unwashed crude RSV preparations or the purified intact RSV. Neutrophils were also challenged with purified RSV G-glycoprotein. The effect of challenging human neutrophils with these preparations of intact RSV, or the RSV G-glycoprotein, was assessed by measuring the cell surface expression of CD11b and CD18b, the phagocytic oxidative burst, and intracellular release of calcium pools. Neutrophils challenged with the washed RSV exhibited significantly lower activation of surface marker expression ( P < < < < 0·001) and oxidative burst ( P < < < < 0·001) than those challenged with unwashed virus or with virus free supernatant. There was no increase in intracellular calcium release on exposure to the washed RSV. Purified G glycoprotein did not stimulate neutrophils, whilst the use of a blocking antibody to the F protein did not prevent unwashed RSV from activating cytotoxic responses. These results suggest that neutrophils have no innate signalling system that recognizes RSV but they are activated at sites of RSV infection as a result of the cytokines and inflammatory molecules released by virally infected cells.

Pretreatment with Recombinant Human Vascular Endothelial Growth Factor Reduces Virus Replication and Inflammation in a Perinatal Lamb Model of Respiratory Syncytial Virus Infection

“…Neutrophilic exocytosis is a major cause of epithelial damage and airway obstruction contributing to ventilation compromise during RSV disease in children (37,42). VEGF interaction with endothelium can regulate adhesion molecule expression and even enhance neutrophil emigration; however, in this case the reduced neutrophil recruitment was likely due to diminished virus replication as this is a significant regulator of neutrophil emigration in RSV disease (4,22,43).…”

Ciliary dyskinesia is an early feature of respiratory syncytial virus infection

“…In our experience the rapid onset of ciliostasis is frequently attributed to the presence of a toxin or to the nonphysiological nature of the carrier fluid; solutions with a low pH can cause rapid ciliostasis [18]. Another study reported that the addition of unwashed ultraviolet-irradiated RSV increased toxicity to HeLa cells, suggesting their viral preparation may have contained a toxic contaminant [13]. However, it is possible that the factors other than the presence of virus resulted in the rapid ciliostasis seen in the study by TRISTRAM et al [6].…”

“…Stocks were harvested by disruption with glass beads for 1 min and the supernatant was centrifuged at 10006g for 5 min to remove cell debris. The filtrate was then purified by centrifugation through a polyethersulfone membrane with a pore size of 1000 kDa molecular weight cut-off (Vivaspin-20; Vivascience, Gloucester, UK), as previously described [13]. The virus fractions were collected and pooled in bronchial epithelial cell basal medium (BEBM; Lonza, Slough, UK), and aliquots containing about 0.5-1610 6 plaque-forming units (PFU)?mL -1 were stored at -80uC.…”

Respiratory syncytial virus-like nanoparticle vaccination induces long-term protection without pulmonary disease by modulating cytokines and&nbsp;T-cells partially through alveolar macrophages

“…The cause of FI-RSV vaccine-enhanced disease is not fully understood yet, but is assumed to be caused by multiple parameters including FI-RSV vaccine-induced Th2-biased immune responses (IL-4, IL-5, IL-13), neutrophils, and eosinophil infiltration in lungs after RSV infection. 33,34 The general features of FI-RSV vaccine-enhanced disease as represented by pulmonary histopathology in humans could be recapitulated in mice. However, detailed pathological features of RSV disease appear to be different in mice and humans.…”