Gamma-irradiation-killed Streptococcus pneumoniae potently induces the expression of IL-6 and IL-8 in human bronchial epithelial cells

Publication date: Available online 14 August 2018Source: Microbial PathogenesisAuthor(s): Min Yong Jwa, Eun Byeol Ko, Hyun Young Kim, Sun Kyung Kim, Soyoung Jeong, Ho Seong Seo, Cheol-Heui Yun, Seung Hyun HanAbstractStreptococcus pneumoniae is a major respiratory pathogen that can cause pneumonia, meningitis, and otitis media. Although capsular polysaccharide-based vaccines are commercially available, there is a need for broad-spectrum, serotype-independent, and cost-effective vaccines. Recently, an intranasal vaccine formulated with gamma-irradiated nonencapsulated S. pneumoniae whole cells has been developed and its immunogenicity is under investigation. Since innate immunity influences the subsequent adaptive immunity, in the present study, we investigated the immunostimulatory activity of gamma-irradiated S. pneumoniae (r-SP) in the human bronchial epithelial cell-line, BEAS-2B, by comparing with heat-inactivated S. pneumoniae (h-SP) and formalin-inactivated S. pneumoniae (f-SP). r-SP potently induced interleukin (IL)-6 and IL-8 at both mRNA and protein levels in a dose- and time-dependent manner, whereas h-SP and f-SP poorly induced them. Of note, the mRNA levels of IL-6 and IL-8 were approximately two-fold higher when cells were stimulated with 3 × 107 CFU/ml of r-SP for 3 h, while the protein levels of IL-6 and IL-8 were approximately five-fold higher after stimulation with 3 × 107 CFU/ml of r-SP for 24 h. Furthermore, r-SP exhibited potent activation...
Source: Microbial Pathogenesis - Category: Infectious Diseases Source Type: research