title: CD45 isoform phenotypes of human T cells: CD4(+)CD45RA(-)RO(+) memory T cells re-acquire CD45RA without losing CD45RO.
abstract: We have studied the alterations in CD45R phenotypes of CD4(+)CD45RA(-)RO(+) T cells in recipients of T cell-depleted bone marrow grafts. These patients are convenient models because early after transplantation, their T cell compartment is repopulated through expansion of mature T cells and contains only cells with a memory phenotype. In addition, re-expression of CD45RA by former CD4(+)CD45RA(-) T cells can be accurately monitored in the pool of recipient T cells that, in the absence of recipient stem cells, can not be replenished with CD45RA(+) T cells through the thymic pathway. We found that CD4(+)CD45RA(-)RO(+) recipient T cells could re-express CD45RA but never reverted to a genuine CD4(+)CD45RA(+)RO(-) naive phenotype. Even 5 years after transplantation, they still co-expressed CD45RO. In addition, the level of CD45RA and CD45RC expression was lower ( approximately 35 %) than that of naive cells. In contrast, the level of CD45RB expression was comparable to that of naive cells. We conclude that CD4(+)CD45RA(-)RO(+) T cells may re-express CD45(high) isoforms but remain distinguishable from naive cells by their lower expression of CD45RA / RC and co-expression of CD45RO. Therefore, it is likely that the long-lived memory T cell will be found in the population expressing both low and high molecular CD45 isoforms.
authors.affiliation: Division of Immunology and Allergology Department of Internal Medicine, University Hospital, Geneva, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Arlettaz
authors.forename: C
authors.initials: C
authors.lastname: Barbey
authors.forename: F
authors.initials: F
authors.lastname: Dumont-Girard
authors.forename: C
authors.initials: C
authors.lastname: Helg
authors.forename: B
authors.initials: B
authors.lastname: Chapuis
authors.forename: E
authors.initials: E
authors.lastname: Roux
authors.forename: E
authors.initials: E
authors.lastname: Roosnek
mesh_terms: D000328:Adult; D016026:Bone Marrow Transplantation; D015704:CD4 Antigens / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory / Q000235:genetics / Q000276:immunology*; D017493:Leukocyte Common Antigens / Q000235:genetics / Q000276:immunology*; D008297:Male; D020033:Protein Isoforms / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014181:Transplantation Immunology
chemical_list: D015704:CD4 Antigens; D020033:Protein Isoforms; D017493:Leukocyte Common Antigens