RT Journal Article
SR Electronic
T1 Interactions of BPIFA1 and BPIFB1 with <em>S. aureus</em>
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP PA3975
DO 10.1183/13993003.congress-2016.PA3975
VO 48
IS suppl 60
A1 Chloe Marshall
A1 Lynne Bingle
A1 Colin Bingle
YR 2016
UL http://erj.ersjournals.com/content/48/suppl_60/PA3975.abstract
AB As part of a robust innate immune system, the cells of the airway epithelium secrete fluid and proteins to create the highly proteinaceous periciliary liquid (PCL). Many proteins present in the PCL have proposed antimicrobial functions, including two of the most abundant proteins, BPIFA1 (SPLUNC1) and BPIFB1 (LPLUNC1). The function of these two proteins in host defence is unresolved and we hypothesize that they interact with the respiratory pathogen, S. aureus, to limit infection.Air-liquid interface (ALI) cultures of primary bronchial epithelial cells secrete many proteins present in the PCL, including BPIFA1 and BPIFB1. Pull down assays interacting cell secretions with S. aureus were used to visualise protein-bacterial interactions. Both BPIFA1 and BPIFB1 were shown interact strongly with S. aureus. Recombinant proteins generated in CHO cells exhibited similar binding to the endogenous proteins. Deglycosylation using PNGase F treatment prior to pull down assays highlighted that these interactions were not dependent on the glycosylation state of BPIFA1 or BPIFB1.We next used adhesion molecule/surface protein mutants of S. aureus from the Nebraska Transposon Mutant library in pull down assays to identify possible S. aureus proteins responsible for interactions with BPIFA1 and BPIFB1. Of the 10 mutants chosen for this study, none were identified as mediating these interactions suggesting the involvement of non-specific interactions.Our study has shown that BPIFA1 and BPIFB1 form strong interactions with the surface of S. aureus, in a potentially non-specific manner. The functional consequences of which remain unresolved but support the notion that BPIFA1 and BPIFB1 play a role in protecting airway epithelial cells from infection.