title: The relationship between human effector and memory T cells measured by ex vivo and cultured ELISPOT following recent and distal priming.
abstract: Maintenance of T-cell responses is an essential feature in protection from many infectious diseases that must be harnessed in vaccination. The relationship between effector T-cell responses and more durable and highly proliferative T-cell memory, particularly in humans, is not well understood. In this study, effector T-cell responses were measured by overnight ex vivo interferon-gamma (IFN-gamma) enzyme-linked immunosorbent spot-forming cell assay (ELISPOT), whereas memory T cells were measured by 10-day culture followed by IFN-gamma ELISPOT (cultured ELISPOT). We observed a significant correlation between IFN-gamma responses to CD4-stimulatory, but not to CD8-stimulatory, recall antigens measured by these assays, suggesting a divergence in regulation. In vaccine trial participants who received a prime-boost vaccination regimen comprising malaria antigens delivered by poxviruses, there was a correlation between ex vivo and cultured responses on day 7, but not 3 months post-vaccination, with the ratio of cultured : ex vivo response increasing over time. To compare responses revealed by cultured ELISPOT in more detail, tetramers comprising viral recall antigens were used to ascribe effector-memory and central-memory T-cell phenotypes through CCR7 and CD62L costaining. For CD8(+) responses the effector phenotype decreased during the initial culture period and memory populations remained high within the resulting 20-fold to 50-fold increased IFN-gamma-secreting or tetramer(+) population. This was less marked for CD4(+) responses, which had higher starting memory phenotype. Depletion of these central-memory T-cell populations generally ablated responses in cultured ELISPOT and reduced ex vivo responses. This study highlights differences between CD4(+) and CD8(+) effector and memory T cells, and the more complex phenotype of CD4(+) T cells.
authors.affiliation: Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK. stephen.todryk@northumbria.ac.uk
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Todryk
authors.forename: Ansar A
authors.initials: AA
authors.lastname: Pathan
authors.forename: Sheila
authors.initials: S
authors.lastname: Keating
authors.forename: David W
authors.initials: DW
authors.lastname: Porter
authors.forename: Tamara
authors.initials: T
authors.lastname: Berthoud
authors.forename: Fiona
authors.initials: F
authors.lastname: Thompson
authors.forename: Paul
authors.initials: P
authors.lastname: Klenerman
authors.forename: Adrian V S
authors.initials: AV
authors.lastname: Hill
mesh_terms: D000293:Adolescent; D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D017780:Malaria Vaccines / Q000276:immunology; D008875:Middle Aged; D014373:Tuberculin / Q000276:immunology; D014611:Vaccination; D055815:Young Adult
chemical_list: D007376:Interleukin-2; D017780:Malaria Vaccines; D014373:Tuberculin; D007371:Interferon-gamma
references.citation: J Virol. 2004 Jul;78(13):7284-7
references.pmid: 15194806
references.citation: PLoS One. 2008 Apr 30;3(4):e2027
references.pmid: 18446217
references.citation: Gene Ther. 2006 Jul;13(14):1110-7
references.pmid: 16525482
references.citation: J Immunol. 2005 Jan 15;174(2):1037-45
references.pmid: 15634928
references.citation: J Immunol Methods. 2002 Feb 1;260(1-2):157-72
references.pmid: 11792386
references.citation: J Virol. 2006 May;80(10):4717-28
references.pmid: 16641265
references.citation: Nat Immunol. 2003 Mar;4(3):225-34
references.pmid: 12563257
references.citation: Infect Immun. 2006 May;74(5):2706-16
references.pmid: 16622207
references.citation: J Immunol. 2007 Apr 1;178(7):4455-65
references.pmid: 17372003
references.citation: J Immunol. 2005 Sep 15;175(6):3502-7
references.pmid: 16148092
references.citation: Nat Med. 2004 Apr;10(4):406-10
references.pmid: 15034567
references.citation: J Immunol. 2006 Apr 15;176(8):4682-9
references.pmid: 16585561
references.citation: J Immunol. 2008 May 1;180(9):5907-15
references.pmid: 18424710
references.citation: Nature. 1999 Oct 14;401(6754):708-12
references.pmid: 10537110
references.citation: Infect Immun. 2006 Feb;74(2):1416-8
references.pmid: 16428796
references.citation: J Exp Med. 1997 Sep 15;186(6):859-65
references.pmid: 9294140
references.citation: J Infect Dis. 2006 Oct 1;194(7):984-92
references.pmid: 16960787
references.citation: J Immunol. 2007 Apr 15;178(8):5217-26
references.pmid: 17404305
references.citation: Science. 2007 Aug 3;317(5838):622-5
references.pmid: 17673652
references.citation: PLoS One. 2008 Jan 30;3(1):e1493
references.pmid: 18231580
references.citation: J Immunol. 2001 Nov 1;167(9):5217-25
references.pmid: 11673535
references.citation: Science. 2006 Jun 9;312(5779):1530-3
references.pmid: 16763152
references.citation: J Immunol. 2005 Nov 15;175(10):6334-43
references.pmid: 16272285
references.citation: Nat Med. 2003 Jun;9(6):729-35
references.pmid: 12766765
references.citation: J Immunol. 2005 Nov 1;175(9):5675-80
references.pmid: 16237057
references.citation: Annu Rev Immunol. 2004;22:745-63
references.pmid: 15032595
references.citation: J Immunol. 2002 Aug 15;169(4):2210-4
references.pmid: 12165552