title: Clonal evolution of CD8+ T cell responses against latent viruses: relationship among phenotype, localization, and function.
abstract: Human cytomegalovirus (hCMV) infection is characterized by a vast expansion of resting effector-type virus-specific T cells in the circulation. In mice, interleukin-7 receptor α (IL-7Rα)-expressing cells contain the precursors for long-lived antigen-experienced CD8(+) T cells, but it is unclear if similar mechanisms operate to maintain these pools in humans. Here, we studied whether IL-7Rα-expressing cells obtained from peripheral blood (PB) or lymph nodes (LNs) sustain the circulating effector-type hCMV-specific pool. Using flow cytometry and functional assays, we found that the IL-7Rα(+) hCMV-specific T cell population comprises cells that have a memory phenotype and lack effector features. We used next-generation sequencing of the T cell receptor to compare the clonal repertoires of IL-7Rα(+) and IL-7Rα(-) subsets. We observed limited overlap of clones between these subsets during acute infection and after 1 year. When we compared the hCMV-specific repertoire between PB and paired LNs, we found many identical clones but also clones that were exclusively found in either compartment. New clones that were found in PB during antigenic recall were only rarely identical to the unique LN clones. Thus, although PB IL-7Rα-expressing and LN hCMV-specific CD8(+) T cells show typical traits of memory-type cells, these populations do not seem to contain the precursors for the novel hCMV-specific CD8(+) T cell pool during latency or upon antigen recall. IL-7Rα(+) PB and LN hCMV-specific memory cells form separate virus-specific compartments, and precursors for these novel PB hCMV-specific CD8(+) effector-type T cells are possibly located in other secondary lymphoid tissues or are being recruited from the naive CD8(+) T cell pool.
  
  
  OBJECTIVE
  Insight into the self-renewal properties of long-lived memory CD8(+) T cells and their location is crucial for the development of both passive and active vaccination strategies. Human CMV infection is characterized by a vast expansion of resting effector-type cells. It is, however, not known how this population is maintained. We here investigated two possible compartments for effector-type cell precursors: circulating acute-phase IL-7Rα-expressing hCMV-specific CD8(+) T cells and lymph node (LN)-residing hCMV-specific (central) memory cells. We show that new clones that appear after primary hCMV infection or during hCMV reactivation seldom originate from either compartment. Thus, although identical clones may be maintained by either memory population, the precursors of the novel clones are probably located in other (secondary) lymphoid tissues or are recruited from the naive CD8(+) T cell pool.
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands Renal Transplant Unit, Department of Internal Medicine, Academic Medical Center, Amsterdam, the Netherlands e.b.remmerswaal@amc.uva.nl.
authors.forename: Ester B M
authors.initials: EB
authors.lastname: Remmerswaal
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands Department of Clinical Immunology and Rheumatology, Academic Medical Center, Amsterdam, the Netherlands Department of Genome Analysis, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Klarenbeek
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Nuno L
authors.initials: NL
authors.lastname: Alves
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands Department of Clinical Immunology and Rheumatology, Academic Medical Center, Amsterdam, the Netherlands Department of Genome Analysis, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Marieke E
authors.initials: ME
authors.lastname: Doorenspleet
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Barbera D C
authors.initials: BD
authors.lastname: van Schaik
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands Department of Clinical Immunology and Rheumatology, Academic Medical Center, Amsterdam, the Netherlands Department of Genome Analysis, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Rebecca E E
authors.initials: RE
authors.lastname: Esveldt
authors.affiliation: Department of Surgery, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Mirza M
authors.initials: MM
authors.lastname: Idu
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Ester M M
authors.initials: EM
authors.lastname: van Leeuwen
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands Renal Transplant Unit, Department of Internal Medicine, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Nelly
authors.initials: N
authors.lastname: van der Bom-Baylon
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Antoine H C
authors.initials: AH
authors.lastname: van Kampen
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Sven D
authors.initials: SD
authors.lastname: Koch
authors.affiliation: Institute of Immunology, University of Freiburg, Freiburg, Germany.
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Pircher
authors.affiliation: Renal Transplant Unit, Department of Internal Medicine, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Frederike J
authors.initials: FJ
authors.lastname: Bemelman
authors.affiliation: Sanquin Research at CLB, Amsterdam, the Netherlands.
authors.forename: Anja
authors.initials: A
authors.lastname: Ten Brinke
authors.affiliation: Department of Genome Analysis, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Frank
authors.initials: F
authors.lastname: Baas
authors.affiliation: Renal Transplant Unit, Department of Internal Medicine, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Ineke J M
authors.initials: IJ
authors.lastname: Ten Berge
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, the Netherlands Sanquin Research at CLB, Amsterdam, the Netherlands.
authors.forename: Rene A W
authors.initials: RA
authors.lastname: van Lier
authors.affiliation: Department of Clinical Immunology and Rheumatology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Niek
authors.initials: N
authors.lastname: de Vries
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000145:classification / Q000276:immunology*; D060965:Clonal Evolution; D003587:Cytomegalovirus / Q000276:immunology* / Q000502:physiology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D020395:Receptors, Interleukin-7 / Q000032:analysis; D016176:T-Lymphocyte Subsets / Q000737:chemistry / Q000145:classification / Q000276:immunology*; D017735:Virus Latency; D055815:Young Adult
chemical_list: D020395:Receptors, Interleukin-7; C415350:interleukin-7 receptor, alpha chain