title: Experimental human pneumococcal carriage augments IL-17A-dependent T-cell defence of the lung.
abstract: Pneumococcal carriage is both immunising and a pre-requisite for mucosal and systemic disease. Murine models of pneumococcal colonisation show that IL-17A-secreting CD4(+) T-cells (Th-17 cells) are essential for clearance of pneumococci from the nasopharynx. Pneumococcal-responding IL-17A-secreting CD4(+) T-cells have not been described in the adult human lung and it is unknown whether they can be elicited by carriage and protect the lung from pneumococcal infection. We investigated the direct effect of experimental human pneumococcal nasal carriage (EHPC) on the frequency and phenotype of cognate CD4(+) T-cells in broncho-alveolar lavage and blood using multi-parameter flow cytometry. We then examined whether they could augment ex vivo alveolar macrophage killing of pneumococci using an in vitro assay. We showed that human pneumococcal carriage leads to a 17.4-fold (p = 0.007) and 8-fold (p = 0.003) increase in the frequency of cognate IL-17A(+) CD4(+) T-cells in BAL and blood, respectively. The phenotype with the largest proportion were TNF(+)/IL-17A(+) co-producing CD4(+) memory T-cells (p<0.01); IFNγ(+) CD4(+) memory T-cells were not significantly increased following carriage. Pneumococci could stimulate large amounts of IL-17A protein from BAL cells in the absence of carriage but in the presence of cognate CD4(+) memory T-cells, IL-17A protein levels were increased by a further 50%. Further to this we then show that alveolar macrophages, which express IL-17A receptors A and C, showed enhanced killing of opsonised pneumococci when stimulated with rhIL-17A (p = 0.013). Killing negatively correlated with RC (r = -0.9, p = 0.017) but not RA expression. We conclude that human pneumococcal carriage can increase the proportion of lung IL-17A-secreting CD4(+) memory T-cells that may enhance innate cellular immunity against pathogenic challenge. These pathways may be utilised to enhance vaccine efficacy to protect the lung against pneumonia.
authors.affiliation: Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom. aw287@le.ac.uk
authors.forename: Adam K A
authors.initials: AK
authors.lastname: Wright
authors.forename: Mathieu
authors.initials: M
authors.lastname: Bangert
authors.forename: Jenna F
authors.initials: JF
authors.lastname: Gritzfeld
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Ferreira
authors.forename: Kondwani C
authors.initials: KC
authors.lastname: Jambo
authors.forename: Angela D
authors.initials: AD
authors.lastname: Wright
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Collins
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Gordon
mesh_terms: D000293:Adolescent; D000328:Adult; D018893:Bronchoalveolar Lavage; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002353:Carrier State / Q000276:immunology* / Q000382:microbiology; D002452:Cell Count; D005260:Female; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D020381:Interleukin-17 / Q000276:immunology*; D008168:Lung / Q000276:immunology* / Q000382:microbiology; D008297:Male; D009305:Nasopharynx / Q000382:microbiology; D011008:Pneumococcal Infections / Q000276:immunology* / Q000382:microbiology / Q000635:transmission; D013296:Streptococcus pneumoniae / Q000276:immunology* / Q000302:isolation & purification; D055815:Young Adult
chemical_list: C508717:IL17A protein, human; D020381:Interleukin-17
references.citation: J Infect Dis. 2009 Sep 1;200(5):783-93
references.pmid: 19642930
references.citation: Immunobiology. 2012 Apr;217(4):420-9
references.pmid: 22204818
references.citation: PLoS One. 2011;6(10):e25558
references.pmid: 22003400
references.citation: PLoS Pathog. 2010 Nov 11;6(11):e1001191
references.pmid: 21085613
references.citation: PLoS Pathog. 2012;8(4):e1002622
references.pmid: 22496648
references.citation: J Exp Med. 2010 Jun 7;207(6):1293-305
references.pmid: 20498020
references.citation: Sci Transl Med. 2011 Oct 12;3(104):104ra100
references.pmid: 21998407
references.citation: J Immunol. 2007 Oct 15;179(8):5462-73
references.pmid: 17911633
references.citation: Clin Diagn Lab Immunol. 2003 Nov;10(6):1019-24
references.pmid: 14607861
references.citation: PLoS Pathog. 2012;8(4):e1002660
references.pmid: 22563306
references.citation: J Clin Immunol. 2010 Jul;30(4):539-45
references.pmid: 20437253
references.citation: Eur J Immunol. 2011 Jul;41(7):1894-901
references.pmid: 21469124
references.citation: Innate Immun. 2013 Oct;19(5):479-92
references.pmid: 23295184
references.citation: Lancet Infect Dis. 2004 Mar;4(3):144-54
references.pmid: 14998500
references.citation: Am J Respir Cell Mol Biol. 2002 Jun;26(6):748-53
references.pmid: 12034575
references.citation: J Immunol. 2004 Sep 1;173(5):3482-91
references.pmid: 15322213
references.citation: Infect Immun. 2004 May;72(5):2689-97
references.pmid: 15102777
references.citation: Am J Respir Cell Mol Biol. 2005 Sep;33(3):248-53
references.pmid: 15901616
references.citation: PLoS Pathog. 2011 Aug;7(8):e1002175
references.pmid: 21852948
references.citation: J Immunol. 2008 Nov 1;181(9):6117-24
references.pmid: 18941201
references.citation: Vaccine. 2010 May 21;28(23):3902-4
references.pmid: 20398618
references.citation: J Gen Physiol. 2006 May;127(5):591-604
references.pmid: 16636206
references.citation: Nat Commun. 2012;3:1119
references.pmid: 23047677
references.citation: Nat Med. 2008 Mar;14(3):275-81
references.pmid: 18264110
references.citation: Infect Immun. 2010 Dec;78(12):5287-94
references.pmid: 20855509
references.citation: Infect Immun. 2008 Jun;76(6):2678-84
references.pmid: 18391006
references.citation: J Immunol. 2006 Dec 1;177(11):7980-9
references.pmid: 17114471
references.citation: Infect Immun. 2002 Sep;70(9):5019-25
references.pmid: 12183548
references.citation: PLoS Pathog. 2011 Dec;7(12):e1002396
references.pmid: 22144893
references.citation: PLoS One. 2011;6(9):e25610
references.pmid: 21980502
references.citation: J Infect Dis. 2012 Sep 1;206(5):723-34
references.pmid: 22723642
references.citation: Vaccine. 2012 Jun 6;30(26):3897-907
references.pmid: 22504663
references.citation: Nat Immunol. 2011 Jun 12;12(7):639-46
references.pmid: 21666689
references.citation: J Vis Exp. 2013 Feb 15;(72):
references.pmid: 23439027
references.citation: PLoS One. 2011;6(10):e25367
references.pmid: 22039412
references.citation: J Infect. 2006 Jan;52(1):37-48
references.pmid: 16368459
references.citation: PLoS Pathog. 2008 Sep 19;4(9):e1000159
references.pmid: 18802458
references.citation: Crit Care. 2011;15(5):R254
references.pmid: 22026963
references.citation: Blood. 2008 Oct 1;112(7):2826-35
references.pmid: 18664624
references.citation: Cytokine Growth Factor Rev. 2010 Dec;21(6):443-8
references.pmid: 21095154
references.citation: Thorax. 2011 May;66(5):375-82
references.pmid: 21357587
references.citation: Infect Immun. 2011 May;79(5):1842-7
references.pmid: 21321074
references.citation: Nat Med. 2012 Mar 04;18(4):547-54
references.pmid: 22388091
references.citation: Inflammation. 2011 Feb;34(1):1-9
references.pmid: 20339909
references.citation: Infect Immun. 2000 Feb;68(2):492-501
references.pmid: 10639409
references.citation: Nat Immunol. 2011 Sep 04;12(10):966-74
references.pmid: 21892173
references.citation: Am J Respir Crit Care Med. 2012 Nov 1;186(9):824-9
references.pmid: 22798317
references.citation: J Immunol. 2008 Sep 15;181(6):4279-86
references.pmid: 18768886
references.citation: J Immunol. 2009 Apr 15;182(8):4507-11
references.pmid: 19342622
references.citation: Immunobiology. 2010 Apr;215(4):251-63
references.pmid: 20071053
references.citation: Nat Immunol. 2007 Apr;8(4):369-77
references.pmid: 17351619
references.citation: J Infect Dis. 2007 Apr 15;195(8):1194-202
references.pmid: 17357058
references.citation: Cell Tissue Res. 2006 Jun;324(3):449-56
references.pmid: 16501999
references.citation: J Leukoc Biol. 2011 Aug;90(2):263-70
references.pmid: 21486905
references.citation: J Clin Invest. 2009 Jul;119(7):1899-909
references.pmid: 19509469
references.citation: J Clin Invest. 2009 Dec;119(12):3573-85
references.pmid: 19920355