Polyinosine-polycytidylic acid enhances cellular adherence of Streptococcus pneumoniae.

Abstract

Viral upper respiratory tract infections (URIs) are often followed by secondary bacterial infections. To better understand this phenomenon, we examined the impact of the viral agent polyinosine-polycytidylic acid [Poly (I:C)] on the adherence of Streptococcus pneumoniae (Spn) to pharyngeal epithelial cells. In vitro model of cultured human pharyngeal epithelial cells. Detroit 562 cells, a human pharyngeal carcinoma cell line, were pretreated with Poly (I:C). Poly (I:C)-induced expression of platelet-activating factor receptor (PAF-R) was assayed using real-time polymerase chain reaction, flow cytometry, and immunofluorescence microscopy. Bacterial adhesion to these epithelial cells was assessed using immunofluorescence microscopy and colony formation assays. Pretreatment with Poly (I:C) increased mRNA and protein expression of PAF-R in Detroit 562 cells and enhanced the adherence of Spn to these epithelial cells. RNA viral infection can enhance PAF-R expression in epithelial cells and increase the adherence of Spn. These findings might explain in part the mechanisms that underlie the increase in bacterial infection following URIs.