title: Increased frequency of CD25dimCD4+ T-cells in HIV-2 infection, a naturally occurring attenuated form of HIV-1.
abstract: The ability to maintain the CD4-memory pool is currently considered one of the main determinants of AIDS progression. Like HIV-1, HIV-2 infection is characterized by progressive hyper-immune activation, yet it is associated with slower rates of CD4-loss and reduced viremia irrespective of disease stage. In contrast to HIV-1, we observed an increased proportion of CD4(+) T-cells expressing CD25 in HIV-2 infected individuals, independent of the degree of CD4-depletion and levels of immune activation. This was due to CD4(+) T-cells expressing an intermediate intensity of CD25, characterized by an increased ability to produce IL-2 and a lack of other regulatory markers. This expansion, unique to HIV-2 seropositive individuals, may relate to an improved ability to replenish their CD4-memory pool, and thus to the better prognosis that characterizes HIV-2 infection. Identification of the underlying mechanisms regulating this population in HIV-1 and HIV-2 infections may provide a rational for novel therapeutic strategies.
authors.affiliation: Unidade de Imunologia Clínica, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal.
authors.forename: Russell B
authors.initials: RB
authors.lastname: Foxall
authors.forename: Rui S
authors.initials: RS
authors.lastname: Soares
authors.forename: Adriana S
authors.initials: AS
authors.lastname: Albuquerque
authors.forename: Catarina S
authors.initials: CS
authors.lastname: Cortesão
authors.forename: Rui M M
authors.initials: RM
authors.lastname: Victorino
authors.forename: Ana E
authors.initials: AE
authors.lastname: Sousa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D015331:Cohort Studies; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D015658:HIV Infections / Q000097:blood / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000276:immunology*; D015498:HIV-2 / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology*; D007376:Interleukin-2 / Q000097:blood / Q000276:immunology; D053645:Interleukin-2 Receptor alpha Subunit / Q000096:biosynthesis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D016176:T-Lymphocyte Subsets / Q000276:immunology; D019562:Viral Load; D014766:Viremia / Q000097:blood / Q000821:virology
chemical_list: D004279:DNA, Viral; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit