Pneumolysin activates the NLRP3 inflammasome and promotes proinflammatory cytokines independently of TLR4
AuthorsMcNeela, Edel A.
Neill, Daniel R
Fernandes, Vitor E.
McLoughlin, Rachel M.
Fitzgerald, Katherine A.
Andrew, Peter W.
Lavelle, Ed C.
UMass Chan AffiliationsDepartment of Medicine, Division of Infectious Diseases and Immunology
Document TypeJournal Article
Enzyme-Linked Immunosorbent Assay
Killer Cells, Natural
Mice, Inbred BALB C
Mice, Inbred C3H
Mice, Inbred C57BL
Toll-Like Receptor 4
Immunology and Infectious Disease
MetadataShow full item record
AbstractPneumolysin (PLY) is a key Streptococcus pneumoniae virulence factor and potential candidate for inclusion in pneumococcal subunit vaccines. Dendritic cells (DC) play a key role in the initiation and instruction of adaptive immunity, but the effects of PLY on DC have not been widely investigated. Endotoxin-free PLY enhanced costimulatory molecule expression on DC but did not induce cytokine secretion. These effects have functional significance as adoptive transfer of DC exposed to PLY and antigen resulted in stronger antigen-specific T cell proliferation than transfer of DC exposed to antigen alone. PLY synergized with TLR agonists to enhance secretion of the proinflammatory cytokines IL-12, IL-23, IL-6, IL-1beta, IL-1alpha and TNF-alpha by DC and enhanced cytokines including IL-17A and IFN-gamma by splenocytes. PLY-induced DC maturation and cytokine secretion by DC and splenocytes was TLR4-independent. Both IL-17A and IFN-gamma are required for protective immunity to pneumococcal infection and intranasal infection of mice with PLY-deficient pneumococci induced significantly less IFN-gamma and IL-17A in the lungs compared to infection with wild-type bacteria. IL-1beta plays a key role in promoting IL-17A and was previously shown to mediate protection against pneumococcal infection. The enhancement of IL-1beta secretion by whole live S. pneumoniae and by PLY in DC required NLRP3, identifying PLY as a novel NLRP3 inflammasome activator. Furthermore, NLRP3 was required for protective immunity against respiratory infection with S. pneumoniae. These results add significantly to our understanding of the interactions between PLY and the immune system.
SourcePLoS Pathog. 2010 Nov 11;6(11):e1001191. Link to article on publisher's site
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/34885
Related ResourcesLink to Article in PubMed