Efeito de lactoferrina bovina na replicação viral e doença clínica em modelo murino de vírus sincicial respiratório

Abstract

Background : Lactoferrin (LF) is a glycoprotein present in human milk with known antimicrobial effects. In vitro, LF has shown to impair the growth of respiratory syncytial virus (RSV). We sought to assess the effect of bovine (b)LF in RSV replication and different aspects of RSV disease in an in vivo murine model. Methods : BALB/C mice were inoculated with 107 PFU RSV A2 or 10% EMEM. bLF or placebo (DPBS) were administered once or twice daily by oral gavage or intraperitoneal (IP) injection at doses ranging from 2 to 10mg/animal/day, from 48h before until day 4 post-RSV inoculation. Bronchoalveolar lavage, whole lung specimens and serum samples were harvested on day 5 post inoculation to asses RSV loads, lung inflammation and cytokine concentrations. Weight loss, airway obstruction and disease severity were assessed daily in all groups. Results : On day 5 post-inoculation RSV loads, lung inflammation and serum innate, Th1, Th2 and Th17 cytokine concentrations showed no differences between RSV infected mice treated with bLF and RSV untreated mice independent of bLF dosing and administration route (p>0.05). In addition, all bLF groups showed similar weight loss, degree of airway obstruction, and disease severity scores on days 1 to 5 post-inoculation which was comparable to infected untreated mice (p>0.05), but higher than uninfected controls. Conclusions : Administration of oral or IP bLF at different doses did not demonstrate antiviral activity or significant effects on disease severity in the RSV mouse model. Whether these observations could be extrapolated to infants at risk of RSV infection needs to be further explored.