title: Increased numbers and functional activity of CD56⁺ T cells in healthy cytomegalovirus positive subjects.
abstract: Human T cells expressing CD56 are capable of tumour cell lysis following activation with interleukin-2 but their role in viral immunity has been less well studied. Proportions of CD56(+) T cells were found to be highly significantly increased in cytomegalovirus-seropositive (CMV(+) ) compared with seronegative (CMV(-) ) healthy subjects (9.1 ± 1.5% versus 3.7 ± 1.0%; P < 0.0001). Proportions of CD56(+) T cells expressing CD28, CD62L, CD127, CD161 and CCR7 were significantly lower in CMV(+) than CMV(-) subjects but those expressing CD4, CD8, CD45RO, CD57, CD58, CD94 and NKG2C were significantly increased (P < 0.05), some having the phenotype of T effector memory cells. Levels of pro-inflammatory cytokines and CD107a were significantly higher in CD56(+) T cells from CMV(+) than CMV(-) subjects following stimulation with CMV antigens. This also resulted in higher levels of proliferation in CD56(+) T cells from CMV(+) than CMV(-) subjects. Using Class I HLA pentamers, it was found that CD56(+) T cells from CMV(+) subjects contained similar proportions of antigen-specific CD8(+) T cells to CD56(-) T cells in donors of several different HLA types. These differences may reflect the expansion and enhanced functional activity of CMV-specific CD56(+) memory T cells. In view of the link between CD56 expression and T-cell cytotoxic function, this strongly implicates CD56(+) T cells as being an important component of the cytotoxic T-cell response to CMV in healthy carriers.
authors.affiliation: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, UK.
authors.forename: Mazen
authors.initials: M
authors.lastname: Almehmadi
authors.forename: Brian F
authors.initials: BF
authors.lastname: Flanagan
authors.forename: Naeem
authors.initials: N
authors.lastname: Khan
authors.forename: Suliman
authors.initials: S
authors.lastname: Alomar
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Christmas
mesh_terms: D000328:Adult; D019002:CD56 Antigen / Q000276:immunology*; D002460:Cell Line; D003587:Cytomegalovirus / Q000276:immunology*; D003586:Cytomegalovirus Infections / Q000276:immunology* / Q000821:virology; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000276:immunology; D055815:Young Adult
chemical_list: D019002:CD56 Antigen
keywords: CD56; T cells; cytomegalovirus