Laura Papagno

Publications of Laura Papagno

• Exhausted cytotoxic control of Epstein-Barr virus in human lupus.

  Authors: Martin Larsen, Delphine Sauce, Claire Deback, Laurent Arnaud, Alexis Mathian, Makoto Miyara, David Boutolleau, Christophe Parizot, Karim Dorgham, Laura Papagno, Victor Appay, Zahir Amoura, Guy Gorochov

  PLoS pathogens. 10/2011; 7(10):e1002328.

  Systemic Lupus Erythematosus (SLE) pathology has long been associated with an increased Epstein-Barr Virus (EBV) seropositivity, viremia and cross-reactive serum antibodies specific for both virusSystemic Lupus Erythematosus (SLE) pathology has long been associated with an increased Epstein-Barr Virus (EBV) seropositivity, viremia and cross-reactive serum antibodies specific for both virus and self. It has therefore been postulated that EBV triggers SLE immunopathology, although the mechanism remains elusive. Here, we investigate whether frequent peaks of EBV viral load in SLE patients are a consequence of dysfunctional anti-EBV CD8+ T cell responses. Both inactive and active SLE patients (n = 76 and 42, respectively), have significantly elevated EBV viral loads (P = 0.003 and 0.002, respectively) compared to age- and sex-matched healthy controls (n = 29). Interestingly, less EBV-specific CD8+ T cells are able to secrete multiple cytokines (IFN-γ, TNF-α, IL-2 and MIP-1β) in inactive and active SLE patients compared to controls (P = 0.0003 and 0.0084, respectively). Moreover, EBV-specific CD8+ T cells are also less cytotoxic in SLE patients than in controls (CD107a expression: P = 0.0009, Granzyme B release: P = 0.0001). Importantly, cytomegalovirus (CMV)-specific responses were not found significantly altered in SLE patients. Furthermore, we demonstrate that EBV-specific CD8+ T cell impairment is a consequence of their Programmed Death 1 (PD-1) receptor up-regulation, as blocking this pathway reverses the dysfunctional phenotype. Finally, prospective monitoring of lupus patients revealed that disease flares precede EBV reactivation. In conclusion, EBV-specific CD8+ T cell responses in SLE patients are functionally impaired, but EBV reactivation appears to be an aggravating consequence rather than a cause of SLE immunopathology. We therefore propose that autoimmune B cell activation during flares drives frequent EBV reactivation, which contributes in a vicious circle to the perpetuation of immune activation in SLE patients.

• Changes in T-cell subsets in HIV-HCV-coinfected patients during pegylated interferon-alpha2a plus ribavirin treatment.

  Authors: Marta Massanella, Cristina Tural, Laura Papagno, Elisabet Garcia, Antoni Jou, Margarita Bofill, Brigitte Autran, Bonaventura Clotet, Julià Blanco

  Antiviral therapy. 01/2010; 15(3):333-42.

  We evaluated the effect of different doses of pegylated interferon (PEG-IFN)-alpha2a/ribavirin (RBV) on several T-cell activation markers in HIV-HCV-coinfected patients and their relationship withWe evaluated the effect of different doses of pegylated interferon (PEG-IFN)-alpha2a/ribavirin (RBV) on several T-cell activation markers in HIV-HCV-coinfected patients and their relationship with changes in plasma HCV RNA. Frozen peripheral blood mononuclear cells (PBMCs) from 22 patients receiving two different PEG-IFN-alpha2a schedules were analysed by six-colour flow cytometry. Cell-surface expression of CD38 was quantified. HIV and HCV viral loads, as well as absolute CD4+ and CD8+ T-cell counts, were recorded during the follow up (72 weeks). PEG-IFN-alpha2a/RBV treatment decreased the absolute numbers of CD8+ and CD4+ T-cells. The decrease in CD8+ T-cells was more pronounced, resulting in increased percentages of CD4+ T-cells. Percentages of naive/memory CD4+ T-cell subsets remained unchanged, although the percentage of CD38+CD45RO+ cells significantly increased. By contrast, the CD8+ T-cell compartment significantly reduced the percentage of CD45RO+ cells and HLA-DR+ cells, whereas the percentage of CD38 expressing cells was increased because of a significant increase in cell-surface CD38 expression. Changes in CD8+ T-cells were similar for both PEG-IFN-alpha2a/RBV doses, but high doses induced more severe perturbations in CD4+ T-cells. All changes returned to baseline levels after treatment cessation and, except for the loss of naive CD4+ T-cells, were not associated with virological response. Transient lymphopaenia induced by PEG-IFN-alpha2a/RBV differentially affects T-cell subsets. Activated HLA-DR+ and CD45RO+ cells were selectively reduced in peripheral blood, whereas CD38 expression was up-regulated mainly in memory cells. Increasing PEG-IFN-alpha2a/RBV doses mainly affect CD4+ T-cells but failed to modify clinical outcome.

• Upregulation of IL-7 Receptor {alpha} and Programmed Death 1 marks an epitope-specific CD8+ T cell response that disappears following primary Epstein-Barr virus infection.

  Authors: Delphine Sauce, Martin Larsen, Rachel J. M. Abbott, Andrew D Hislop, Alison M Leese, Naeem Khan, Laura Papagno, Gordon J Freeman, Alan B Rickinson

  Journal of virology. 08/2009;

  In immunocompetent individuals, the stability of the herpesvirus-host balance limits opportunities to study the disappearance of a virus-specific CD8+ T cell response. However, in HLA-A*0201-positiveIn immunocompetent individuals, the stability of the herpesvirus-host balance limits opportunities to study the disappearance of a virus-specific CD8+ T cell response. However, in HLA-A*0201-positive infectious mononucleosis (IM) patients undergoing primary Epstein-Barr virus (EBV) infection, we noticed that the initial CD8 response targets three EBV lytic antigen-derived epitopes, YVL, GLC and TLD, but only the YVL and GLC reactivities persist long-term; the TLD response disappears within 10-27 months. While present, TLD-specific cells remained largely indistinguishable from YVL and GLC reactivities in many phenotypic and functional respects but showed unique temporal changes in two markers of T cell fate, interleukin 7 receptor alpha (IL-7Ralpha, CD127) and programmed death 1 (PD1). Thus, following the antigen-driven down-regulation of IL-7Ralpha seen on all populations in acute IM, in every case the TLD-specific population recovered expression unusually quickly post-IM. Secondly, in four of six patients studied, TLD-specific cells showed very strong PD-1 up-regulation in the last bleed before the cells' disappearance. Our data suggest that the disappearance of this individual epitope reactivity from an otherwise stable EBV-specific response (i) reflects a selective loss of cognate antigen re-stimulation (rather than of IL-7-dependent signals), and (ii) is immediately preceded, and perhaps mediated, by PD-1 up-regulation to unprecedented levels.

• A step ahead on the HIV collaboratory.

  Authors: Robert L Murphy, Brigitte Autran, Christine Katlama, Gilles Brucker, Patrice Debre, Vincent Calvez, Bonaventura Clotet, Nathan Clumeck, Dominique Costagliola, Steven G Deeks [......] Jose Gatell, Ashley Haase, Michel Klein, Adriano Lazzarin, Andrew J McMichael, Laura Papagno, Timothy W Schacker, Simon Wain-Hobson, Bruce D Walker, Michael Youle

  Science (New York, N.Y.). 07/2009; 324(5932):1264-5.

• Antigen sensitivity is a major determinant of CD8+ T-cell polyfunctionality and HIV suppressive activity.

  Authors: Jorge R Almeida, Delphine Sauce, David A Price, Laura Papagno, So Youn Shin, Arnaud Moris, Martin Larsen, Gianfranco Pancino, Daniel C Douek, Brigitte Autran, Asier Saez-Cirion, Victor Appay

  Blood. 05/2009;

  CD8(+) T-cells are major players in the immune response against HIV. However, recent failures in the development of T-cell-based vaccines against HIV-1 have emphasized the need to reassess our basicCD8(+) T-cells are major players in the immune response against HIV. However, recent failures in the development of T-cell-based vaccines against HIV-1 have emphasized the need to reassess our basic knowledge of T-cell-mediated efficacy. CD8(+) T-cells from HIV-1 infected patients with slow disease progression exhibit potent polyfunctionality and HIV suppressive activity, yet the factors that unify these properties are incompletely understood. We performed a detailed study of the interplay between T-cell functional attributes using a bank of HIV-specific CD8(+) T-cell clonotypes isolated in vitro; this approach enabled us to overcome inherent difficulties related to the in vivo heterogeneity of T-cell populations and address the underlying determinants that synthesize the qualities required for antiviral efficacy. Conclusions were supported by ex vivo analysis of HIV specific CD8+ T-cells from infected donors. We report that attributes of CD8(+) T-cell efficacy against HIV are linked at the level of antigen sensitivity. Highly sensitive CD8(+) T-cells display polyfunctional profiles and potent HIV suppressive activity. These data provides news insights into the mechanisms underlying CD8+ T-cell efficacy against HIV, and indicate that vaccine strategies should focus on the induction of HIV-specific T-cells with high levels of antigen sensitivity in order to elicit potent antiviral efficacy.

• Multicentric Castleman disease is associated with polyfunctional effector memory HHV-8-specific CD8+ T cells.

  Authors: Amélie Guihot, Eric Oksenhendler, Lionel Galicier, Anne-Geneviève Marcelin, Laura Papagno, Anne-Sophie Bedin, Félix Agbalika, Nicolas Dupin, Jacques Cadranel, Brigitte Autran, Guislaine Carcelain

  Blood. 03/2008; 111(3):1387-95.

  Multicentric Castleman disease (MCD) is a devastating human herpesvirus 8 (HHV-8)-related lymphoproliferative disorder that occurs in immunocompromised persons. To determine the role of immuneMulticentric Castleman disease (MCD) is a devastating human herpesvirus 8 (HHV-8)-related lymphoproliferative disorder that occurs in immunocompromised persons. To determine the role of immune responses in MCD, we studied the frequency, antigenic repertoire, differentiation, and functional profile of HHV-8-specific CD8(+) T cells in MCD patients and in human immunodeficiency virus-coinfected asymptomatic HHV-8 carriers (AC). Screening CD8(+) T-cell responses with ELISpot interferon-gamma (IFN-gamma) assays using 56 peptides on 6 latent and lytic HHV-8 proteins showed that MCD and AC patients had responses of similar magnitude and antigenic repertoire and identified a new 10-mer human leukocyte antigen B7 CD8 epitope in K15. Intracellular IFN-gamma staining showed significantly more CD45RA(-)CCR7(-)CD27(-) CD8(+)IFN-gamma(+) cells (late phenotype) and significantly fewer CCR7(-)CD27(+)CD45RA(-) cells (early and intermediate phenotype) in MCD than in AC patients. This phenotypic shift was not found for Epstein-Barr virus-specific CD8(+) T cells tested as controls. HHV-8 viral loads were negatively correlated with early and intermediate effector memory cells. HHV-8-specific T cells were polyfunctional (secretion of IFN-gamma, tumor necrosis factor-alpha, macrophage inflammatory protein-1beta, and/or CD107a) in both MCD and AC patients. In conclusion, MCD is not associated with a lack of HHV-8-specific CD8(+) T cells or limitation of their functional profile. Their differentiation increases with HHV-8 viral load. These results offer new insight into the pathophysiology of MCD.

• Cell permeabilization for the assessment of T lymphocyte polyfunctional capacity.

  Authors: Laura Papagno, Jorge R Almeida, Elisa Nemes, Brigitte Autran, Victor Appay

  Journal of immunological methods. 01/2008; 328(1-2):182-8.

  The rapid progress in flow cytometry means that an increasing number of parameters can be looked at simultaneously, which is highly relevant for the assessment of lymphocyte characteristics, inThe rapid progress in flow cytometry means that an increasing number of parameters can be looked at simultaneously, which is highly relevant for the assessment of lymphocyte characteristics, in particular their multifunctional profile. However, procedures using less complex technology need now optimization in order to take into account the new reagents and applications related to polychromatic flow cytometry. Through optimization of an immunomonitoring protocol to assess the functional profile of antigen specific T-cells using 9-10 colour flow cytometry, we tested the efficacy of three distinct standardized permeabilization buffers for the staining of relevant intracellular molecules. We show significant discrepancies in staining sensitivity for cytokine and cytotoxic factor expression from one permeabilization kit to another, which can lead to different data and interpretation. It is important to be aware of this potential bias and to design specific application/experimental procedures in order to obtain optimal results.

• Superior control of HIV-1 replication by CD8+ T cells is reflected by their avidity, polyfunctionality, and clonal turnover.

  Authors: Jorge R Almeida, David A Price, Laura Papagno, Zaïna Aït Arkoub, Delphine Sauce, Ethan Bornstein, Tedi E Asher, Assia Samri, Aurélie Schnuriger, Ioannis Theodorou, Dominique Costagliola, Christine Rouzioux, Henri Agut, Anne-Geneviève Marcelin, Daniel Douek, Brigitte Autran, Victor Appay

  The Journal of experimental medicine. 11/2007; 204(10):2473-85.

  The key attributes of CD8+ T cell protective immunity in human immunodeficiency virus (HIV) infection remain unclear. We report that CD8+ T cell responses specific for Gag and, in particular, theThe key attributes of CD8+ T cell protective immunity in human immunodeficiency virus (HIV) infection remain unclear. We report that CD8+ T cell responses specific for Gag and, in particular, the immunodominant p24 epitope KK10 correlate with control of HIV-1 replication in human histocompatibility leukocyte antigen (HLA)-B27 patients. To understand further the nature of CD8+ T cell-mediated antiviral efficacy, we performed a comprehensive study of CD8+ T cells specific for the HLA-B27-restricted epitope KK10 in chronic HIV-1 infection based on the use of multiparametric flow cytometry together with molecular clonotypic analysis and viral sequencing. We show that B27-KK10-specific CD8+ T cells are characterized by polyfunctional capabilities, increased clonal turnover, and superior functional avidity. Such attributes are interlinked and constitute the basis for effective control of HIV-1 replication. These data on the features of effective CD8+ T cells in HIV infection may aid in the development of successful T cell vaccines.

• Accelerated immune senescence and HIV-1 infection.

  Authors: Victor Appay, Jorge R Almeida, Delphine Sauce, Brigitte Autran, Laura Papagno

  Experimental gerontology. 06/2007; 42(5):432-7.

  A recent consensus has emerged regarding the association between chronic immune activation and poor outcome in HIV-1 infection. However, its basis remains unclear. Accumulating evidence suggests thatA recent consensus has emerged regarding the association between chronic immune activation and poor outcome in HIV-1 infection. However, its basis remains unclear. Accumulating evidence suggests that the cells of the immune system may have a limited replicative lifespan in vivo. In this context, persistent activation during chronic HIV infection may lead to an exhaustion of immune resources. This may occur at two levels: Clonal and Global. Some HIV-1-specific CD8+ T-cells start expressing the senescence marker CD57 soon after primary infection. Persistently activated HIV-1-specific T-cell clones may eventually reach stages of replicative senescence and disappear, resulting in the specific loss of CD8+ T-cell populations important to control viral replication. In addition, HIV-1 infected individuals are characterized by the accumulation of highly differentiated CD8+ and CD4+ T-cells overtime. Together with the decline of T-cell renewal capacities, this may reflect a general ageing of the lymphocyte population. Similar observations have been done in HIV non-infected elderly individuals, which suggests that premature immunosenescence occurs in HIV-1 infection, as a result of persistent immune activation.

• HIV-specific cytotoxic T cells from long-term survivors select a unique T cell receptor.

  Authors: Tao Dong, Guillaume Stewart-Jones, Nan Chen, Philippa Easterbrook, Xiaoning Xu, Laura Papagno, Victor Appay, Michael Weekes, Chris Conlon, Celsa Spina, Susan Little, Gavin Screaton, Anton van der Merwe, Douglas D Richman, Andrew J McMichael, E Yvonne Jones, Sarah L Rowland-Jones

  The Journal of experimental medicine. 01/2005; 200(12):1547-57.

  HIV-specific cytotoxic T lymphocytes (CTL) are important in controlling HIV replication, but the magnitude of the CTL response does not predict clinical outcome. In four donors with delayed diseaseHIV-specific cytotoxic T lymphocytes (CTL) are important in controlling HIV replication, but the magnitude of the CTL response does not predict clinical outcome. In four donors with delayed disease progression we identified Vbeta13.2 T cell receptors (TCRs) with very similar and unusually long beta-chain complementarity determining region 3 (CDR3) regions in CTL specific for the immunodominant human histocompatibility leukocyte antigens (HLA)-B8-restricted human immunodeficiency virus-1 (HIV-1) nef epitope, FLKEKGGL (FL8). CTL expressing Vbeta13.2 TCRs tolerate naturally arising viral variants in the FL8 epitope that escape recognition by other CTL. In addition, they expand efficiently in vitro and are resistant to apoptosis, in contrast to FL8-specific CTL using other TCRs. Selection of Vbeta13.2 TCRs by some patients early in the FL8-specific CTL response may be linked with better clinical outcome.

• Immune activation and CD8+ T-cell differentiation towards senescence in HIV-1 infection.

  Authors: Laura Papagno, Celsa A Spina, Arnaud Marchant, Mariolina Salio, Nathalie Rufer, Susan Little, Tao Dong, Gillian Chesney, Anele Waters, Philippa Easterbrook, P Rod Dunbar, Dawn Shepherd, Vincenzo Cerundolo, Vincent Emery, Paul Griffiths, Christopher Conlon, Andrew J McMichael, Douglas D Richman, Sarah L Rowland-Jones, Victor Appay

  PLoS biology. 03/2004; 2(2):E20.

  Progress in the fight against the HIV/AIDS epidemic is hindered by our failure to elucidate the precise reasons for the onset of immunodeficiency in HIV-1 infection. Increasing evidence suggests thatProgress in the fight against the HIV/AIDS epidemic is hindered by our failure to elucidate the precise reasons for the onset of immunodeficiency in HIV-1 infection. Increasing evidence suggests that elevated immune activation is associated with poor outcome in HIV-1 pathogenesis. However, the basis of this association remains unclear. Through ex vivo analysis of virus-specific CD8(+) T-cells and the use of an in vitro model of naïve CD8(+) T-cell priming, we show that the activation level and the differentiation state of T-cells are closely related. Acute HIV-1 infection induces massive activation of CD8(+) T-cells, affecting many cell populations, not only those specific for HIV-1, which results in further differentiation of these cells. HIV disease progression correlates with increased proportions of highly differentiated CD8(+) T-cells, which exhibit characteristics of replicative senescence and probably indicate a decline in T-cell competence of the infected person. The differentiation of CD8(+) and CD4(+) T-cells towards a state of replicative senescence is a natural process. It can be driven by excessive levels of immune stimulation. This may be part of the mechanism through which HIV-1-mediated immune activation exhausts the capacity of the immune system.

• Immune Activation and CD8⁺ T-Cell Differentiation towards Senescence in HIV-1 Infection

  Authors: Laura Papagno, Spina Celsa A, Arnaud Marchant, Mariolina Salio, Nathalie Rufer, Susan Little, Tao Dong, Gillian Chesney, Anele Waters, Philippa Easterbrook, Dunbar P. Rod, Dawn Shepherd, Vincenzo Cerundolo, Vincent Emery, Paul Griffiths, Christopher Conlon, McMichael Andrew J, Richman Douglas D, Rowland-Jones Sarah L, Victor Appay

  PLoS Biology. 01/2004;

  Progress in the fight against the HIV/AIDS epidemic is hindered by our failure to elucidate the precise reasons for the onset of immunodeficiency in HIV-1 infection. Increasing evidence suggests thatProgress in the fight against the HIV/AIDS epidemic is hindered by our failure to elucidate the precise reasons for the onset of immunodeficiency in HIV-1 infection. Increasing evidence suggests that elevated immune activation is associated with poor outcome in HIV-1 pathogenesis. However, the basis of this association remains unclear. Through ex vivo analysis of virus-specific CD8⁺ T-cells and the use of an in vitro model of naive CD8⁺ T-cell priming, we show that the activation level and the differentiation state of T-cells are closely related. Acute HIV-1 infection induces massive activation of CD8⁺ T-cells, affecting many cell populations, not only those specific for HIV-1, which results in further differentiation of these cells. HIV disease progression correlates with increased proportions of highly differentiated CD8⁺ T-cells, which exhibit characteristics of replicative senescence and probably indicate a decline in T-cell competence of the infected person. The differentiation of CD8⁺ and CD4⁺ T-cells towards a state of replicative senescence is a natural process. It can be driven by excessive levels of immune stimulation. This may be part of the mechanism through which HIV-1-mediated immune activation exhausts the capacity of the immune system.

• Characterization of CD4(+) CTLs ex vivo.

  Authors: Victor Appay, John J Zaunders, Laura Papagno, Julian Sutton, Angel Jaramillo, Anele Waters, Philippa Easterbrook, Pat Grey, Don Smith, Andrew J McMichael, David A Cooper, Sarah L Rowland-Jones, Anthony D Kelleher

  Journal of immunology (Baltimore, Md. : 1950). 07/2002; 168(11):5954-8.

  The cytotoxic potential of CD8(+) T cells and NK cells plays a crucial role in the immune response to pathogens. Although in vitro studies have reported that CD4(+) T cells are also able to mediateThe cytotoxic potential of CD8(+) T cells and NK cells plays a crucial role in the immune response to pathogens. Although in vitro studies have reported that CD4(+) T cells are also able to mediate perforin-mediated killing, the in vivo existence and relevance of cytotoxic CD4(+) T cells have been the subject of debate. Here we show that a population of CD4(+) perforin(+) T cells is present in the circulation at low numbers in healthy donors and is markedly expanded in donors with chronic viral infections, in particular HIV infection, at all stages of the disease, including early primary infection. Ex vivo analysis shows that these cells have cytotoxic potential mediated through the release of perforin. In comparison with more classical CD4(+) T cells, this subset displays a distinct surface phenotype and functional profile most consistent with end-stage differentiated T cells and include Ag experienced CD4(+) T cells. The existence of CD4(+) cytotoxic T cells in vivo at relatively high levels in chronic viral infection suggests a role in the immune response.

• Dynamics of T cell responses in HIV infection.

  Authors: Victor Appay, Laura Papagno, Celsa A Spina, Pokrath Hansasuta, Abigail King, Louise Jones, Graham S Ogg, Susan Little, Andrew J McMichael, Douglas D Richman, Sarah L Rowland-Jones

  Journal of immunology (Baltimore, Md. : 1950). 05/2002; 168(7):3660-6.

  Cytotoxic CD8(+) T cells play a major role in the immune response against viruses. However, the dynamics of CD8(+) T cell responses during the course of a human infection are not well understood.Cytotoxic CD8(+) T cells play a major role in the immune response against viruses. However, the dynamics of CD8(+) T cell responses during the course of a human infection are not well understood. Using tetrameric complexes in combination with a range of intracellular and extracellular markers, we present a detailed analysis of the changes in activation and differentiation undergone by Ag-specific CD8(+) T cells, in relation to Ag-specific CD4(+) T cell responses, in the context of a human infection: HIV-1. During primary HIV-1 infection, the initial population of HIV-specific CD8(+) T cells is highly activated and prone to apoptosis. The Ag-specific cells differentiate rapidly from naive to cells at a perforin low intermediate stage of differentiation, later forming a stable pool of resting cells as viral load decreases during chronic infection. These observations have significant implications for our understanding of T cell responses in human viral infections in general and indicate that the definition of effector and memory subsets in humans may need revision.

• Memory CD8+ T cells vary in differentiation phenotype in different persistent virus infections.

  Authors: Victor Appay, P Rod Dunbar, Margaret Callan, Paul Klenerman, Geraldine M A Gillespie, Laura Papagno, Graham S Ogg, Abigail King, Franziska Lechner, Celsa A Spina [......] Diane V Havlir, Douglas D Richman, Norbert Gruener, Gerd Pape, Anele Waters, Philippa Easterbrook, Mariolina Salio, Vincenzo Cerundolo, Andrew J McMichael, Sarah L Rowland-Jones

  Nature medicine. 05/2002; 8(4):379-85.

  The viruses HIV-1, Epstein-Barr virus (EBV), cytomegalovirus (CMV) and hepatitis C virus (HCV) are characterized by the establishment of lifelong infection in the human host, where their replicationThe viruses HIV-1, Epstein-Barr virus (EBV), cytomegalovirus (CMV) and hepatitis C virus (HCV) are characterized by the establishment of lifelong infection in the human host, where their replication is thought to be tightly controlled by virus-specific CD8+ T cells. Here we present detailed studies of the differentiation phenotype of these cells, which can be separated into three distinct subsets based on expression of the costimulatory receptors CD28 and CD27. Whereas CD8+ T cells specific for HIV, EBV and HCV exhibit similar characteristics during primary infection, there are significant enrichments at different stages of cellular differentiation in the chronic phase of persistent infection according to the viral specificity, which suggests that distinct memory T-cell populations are established in different virus infections. These findings challenge the current definitions of memory and effector subsets in humans, and suggest that ascribing effector and memory functions to subsets with different differentiation phenotypes is no longer appropriate.

• Accelerated immune senescence and HIV-1 infection

  Authors: Victor Appay, Jorge R. Almeida, Delphine Sauce, Brigitte Autran, Laura Papagno

  Experimental Gerontology.

  A recent consensus has emerged regarding the association between chronic immune activation and poor outcome in HIV-1 infection. However, its basis remains unclear. Accumulating evidence suggests thatA recent consensus has emerged regarding the association between chronic immune activation and poor outcome in HIV-1 infection. However, its basis remains unclear. Accumulating evidence suggests that the cells of the immune system may have a limited replicative lifespan in vivo. In this context, persistent activation during chronic HIV infection may lead to an exhaustion of immune resources. This may occur at two levels: Clonal and Global. Some HIV-1-specific CD8+ T-cells start expressing the senescence marker CD57 soon after primary infection. Persistently activated HIV-1-specific T-cell clones may eventually reach stages of replicative senescence and disappear, resulting in the specific loss of CD8+ T-cell populations important to control viral replication. In addition, HIV-1 infected individuals are characterized by the accumulation of highly differentiated CD8+ and CD4+ T-cells overtime. Together with the decline of T-cell renewal capacities, this may reflect a general ageing of the lymphocyte population. Similar observations have been done in HIV non-infected elderly individuals, which suggests that premature immunosenescence occurs in HIV-1 infection, as a result of persistent immune activation.

• Cell permeabilization for the assessment of T lymphocyte polyfunctional capacity

  Authors: Laura Papagno, Jorge R. Almeida, Elisa Nemes, Brigitte Autran, Victor Appay

  Journal of Immunological Methods.

  The rapid progress in flow cytometry means that an increasing number of parameters can be looked at simultaneously, which is highly relevant for the assessment of lymphocyte characteristics, inThe rapid progress in flow cytometry means that an increasing number of parameters can be looked at simultaneously, which is highly relevant for the assessment of lymphocyte characteristics, in particular their multifunctional profile. However, procedures using less complex technology need now optimization in order to take into account the new reagents and applications related to polychromatic flow cytometry. Through optimization of an immunomonitoring protocol to assess the functional profile of antigen specific T-cells using 9–10 colour flow cytometry, we tested the efficacy of three distinct standardized permeabilization buffers for the staining of relevant intracellular molecules. We show significant discrepancies in staining sensitivity for cytokine and cytotoxic factor expression from one permeabilization kit to another, which can lead to different data and interpretation. It is important to be aware of this potential bias and to design specific application/experimental procedures in order to obtain optimal results.