scholarly journals Expansion of Phenotypically Senescent CD57+ CD8 T Cells Is Associated with Impaired Immunocompetence after Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1807-1807
Author(s):  
Sarah Morin ◽  
Amandine Pradier ◽  
Federica Giannotti ◽  
Anne-Claire Mamez ◽  
Diem-Lan Vu-Cantero ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Advisory Board ◽  
Effector Memory ◽  
Healthy Controls ◽  
Hematopoietic Stem ◽  
Memory Cd8 T Cells ◽  
Allogeneic Hsct ◽  
T Cell Senescence

Abstract Background: T cell senescence is a physiological process typically associated with aging. In addition, lymphopenia and chronic immune activation can result in T cell senescence. CD57, a member of the N-CAM family initially described as a natural killer cell marker, has been reported as a marker of human senescent CD8 T cells. Percentages of CD57+ CD8 T cells increase during aging as well as during chronic viral infections. Early studies have reported increased proportions of CD57-expressing CD8 T cells after autologous and allogeneic hematopoietic stem cell transplantation (HSCT). Whether these cells can be considered a counterpart of the senescent population found during aging is at present unknown. More importantly, whether the expansion of CD57+ CD8 T cells is associated with impaired immunocompetence after allogeneic HSCT remains to be investigated. Materials and Methods: With written informed consent, peripheral blood mononuclear cells were collected from healthy controls (HC, n=21) and patients undergoing allogeneic HSCT (n=115) at Geneva University Hospitals. Proportions of CD57+ CD8 T cells as well as phenotypic and functional characteristics of CD57+ CD8 T cells were assessed by flow cytometry. Virus-specific CD8 T cells were identified by flow cytometry based on IFNg and/or TNFa intra-cytoplasmic expression after 6h in vitro stimulation with peptides derived from CMV, EBV, HHV6, BKV and Adenovirus. Torque Teno Virus (TTV) replication was quantified by quantitative PCR as previously described (Pradier et al., Front Immunol 2020; doi: 10.3389/fimmu.2020.00998). Results: CD8 T cells recovered from allogeneic HSCT displayed significantly higher proportions of CD57+ cells compared with healthy controls (HC, median 23% [range 6%-67%]; HSCT 58% [11%-97%]; p= 8.1e−06; Figure 1A-B). Such a difference was detected at early time points after transplantation and further increased at later time points (Figure 1B). After taking into account T cell subsets heterogeneity, we observed higher proportions of CD57+ cells in CD45RA- CCR7+ CD27+ central memory (CM; p= 0.00057), CD45RA- CCR7- CD27+ transitional memory (TM; p=1.1e-05) and CD45RA- CCR7- CD27- effector memory (EM; p=2.6e−06) CD8 T cells from allogeneic HSCT recipients compared with healthy controls. We did not observe any significant differences in CD57 expression in naïve nor in TEMRA CD8 T cells. Phenotypically, CD57+ CD8 T cells from allogeneic HSCT recipients displayed a senescent immunophenotype characterized by the low surface expression of CD127 that was further downregulated in CD57+ CD8 T cells from allogeneic HSCT recipients compared with healthy controls (p=0.00067). Functionally, CD57+ CD8 T cells from allogeneic HSCT recipients displayed a similar capacity to produce IFN-g, TNF-a, granzyme B and perforin when compared to CD57+ CD8 T cells from healthy controls. Virus-specific CD8 T cells identified upon stimulation with CMV, EBV, HHV6, BKV and Adenovirus peptides mainly displayed a CD27- effector memory phenotype in HSCT recipients (Figure 1C) and expressed higher levels of CD57 in HSCT recipients compared with healthy controls for CMV (p=0.017(; EBV p=0.018; Figure 1C-D). with a trend not reaching significance was for adenovirus, HHV6 and BK-virus-specific CD8 T cells. Using the replication of the non-pathogenic anellovirus TTV as a measure of impaired immunocompetence, we observed that the proportion of CD57-expressing cells among effector memory CD8 T cells positively correlated with TTV titers in allogeneic HSCT recipients (R=0.32, p=0.019; Figure 1E). Conclusion: These results show that the proportion of phenotypically senescent CD57+ CD8 T cells increases after allogeneic HSCT as a result of an increased expression at the surface of memory CD8 T cells, including virus-specific cells. Moreover, CD57 expression at the surface of EM CD8 T cells, a highly enriched population in allogeneic HSCT recipients, correlated with higher replication of TTV, reflecting a status of impaired immunocompetence after allogeneic HSCT. Studies are ongoing to determine the utility of CD57 expression on T cells as a biomarker to predict infectious complications after allogeneic HSCT. Figure 1 Figure 1. Disclosures Chalandon: Incyte, BMS, Pfizer, Abbie, MSD, Roche, Novartis, Gilead, Amgen, Jazz, Astra Zenec: Other: Travel EXpenses, Accomodation; Incyte: Speakers Bureau; Incyte, BMS, Pfizer, Abbie, MSD, Roche, Novartis, Amgen: Other: Advisory Board. Simonetta: BMS Cellgene: Other: Ad-Hoc Advisory Board.

scholarly journals Transient and persistent effects of IL-15 on lymphocyte homeostasis in nonhuman primates

Blood ◽  
2010 ◽  
Vol 116 (17) ◽  
pp. 3238-3248 ◽  
Author(s):  
Enrico Lugli ◽  
Carolyn K. Goldman ◽  
Liyanage P. Perera ◽  
Jeremy Smedley ◽  
Rhonda Pung ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
The Body ◽  
Effector Memory ◽  
Memory Cd8 T Cells

Abstract Interleukin-15 (IL-15) is a cytokine with potential therapeutic application in individuals with cancer or immunodeficiency to promote natural killer (NK)– and T-cell activation and proliferation or in vaccination protocols to generate long-lived memory T cells. Here we report that 10-50 μg/kg IL-15 administered intravenously daily for 12 days to rhesus macaques has both short- and long-lasting effects on T-cell homeostasis. Peripheral blood lymphopenia preceded a dramatic expansion of NK cells and memory CD8 T cells in the circulation, particularly a 4-fold expansion of central memory CD8 T cells and a 6-fold expansion of effector memory CD8 T cells. This expansion is a consequence of their activation in multiple tissues. A concomitant inverted CD4/CD8 T-cell ratio was observed throughout the body at day 13, a result of preferential CD8 expansion. Expanded T- and NK-cell populations declined in the blood soon after IL-15 was stopped, suggesting migration to extralymphoid sites. By day 48, homeostasis appears restored throughout the body, with the exception of the maintenance of an inverted CD4/CD8 ratio in lymph nodes. Thus, IL-15 generates a dramatic expansion of short-lived memory CD8 T cells and NK cells in immunocompetent macaques and has long-term effects on the balance of CD4+ and CD8+ T cells.

Flagellin, a TLR5 Agonist, Reduces GvHD in Allogeneic HSCT Recipients While Enhancing Anti-Viral Immunity: A Novel Therapeutic Approach

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 144-144
Author(s):  
Mohammad S Hossain ◽  
David L Jaye ◽  
Brian P Pollack ◽  
Alton B Farr ◽  
John Roback ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Viral Immunity ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Post Transplant ◽  
Radiation Chimeras ◽  
Donor T Cells

Abstract Abstract 144 In MHC-mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT), host antigen specific donor T cells mediate acute and chronic graft-versus-host disease (GvHD). Based upon the radio-protective effects of flagellin, a TLR5 agonist protein (∼50 kDa) extracted from bacterial flagella, we reasoned that flagellin might modulate donor T cells immune responses toward host antigens, reduce GvHD, and improve immune responses to CMV infection in experimental models of allogeneic HSCT. Two 50mg/mouse i.p doses of highly purified flagellin were administered 3 hrs before irradiation and 24 hrs after allo-HSCT in H-2b ^ CB6F1 and H-2k ^ B6 models. GvHD scores were obtained with weekly clinical examination and with histological scoring of intestine, colon, liver and skin at necropsy. Flagellin treatment successfully protected allo-HSCT recipients from acute and chronic GvHDs after transplantation of 5×106 splenocytes and 5×106 T cell depleted (TCD) BM, and significantly increased survival compared to PBS-treated control recipients. Reduced acute GvHD was associated with significant reduction of a) early post-transplant proliferation of donor CD4+ and CD8+ T cells measured by Ki67 and CFSE staining, b) fewer CD62L+, CD69+, CD25+, ICOS-1+ and PD-1+ donor CD4+ and CD8+ T cells compared with the PBS-treated control recipients. Decreased numbers of activated and proliferating donor T cells were associated with significantly reduced pro-inflammatory serum IFN-g, TNF-a, and IL-6 on days 4–10 post transplant in flagellin-treated recipients compared with the PBS-treated recipients. Interestingly, both flagellin-treated recipients and PBS-treated recipients had over 99% donor T cell chimerism at 2 months post transplant. Moreover, MCMV infection on 100+ days post-transplant flagellin-treated mice significantly enhanced anti-viral immunity, including more donor MCMV-peptide-tetramer+ CD8+ T cells in the blood (p<0.05), and less MCMV in the liver on day 10 post infection (p<0.02) compared with the PBS-treated control recipients. Overall immune reconstitution after flagellin-treatment was robust and associated with larger numbers of CD4+CD25+foxp3+ regulatory T cells in the thymus. To further define the role of flagellin-TLR5 agonistic interactions in the reduction of GvHD, we next generated B6 ^ TLR5 KO (KO) and KOB^6 radiation chimeras by transplanting 10 × 106 BM cells from wild-type (WT) B6 or TLR5 KO donors into the congenic CD45.1+ B6 or KO recipients conditioned with 11Gy (5.5Gyx2) TBI. The radiation chimeras were irradiated again with 9.0Gy (4.5Gy × 2) on 60 days after the first transplant and transplanted with 3 × 106 splenocytes and 5 × 106 TCD BM from H-2K congenic donors. Two 50mg doses of flagellin were administered 3 hrs before irradiation and 24 hrs after HSCT. All flagellin-treated B6 ^ B6 radiation chimeras survived with only 12% weight-loss by 80 days post transplant compared with 50% survival among recipients of flagellin-treated B6 ^ KO and 40% survival among KO ^ B6 radiation chimeras. All flagellin-treated KO^ KO and PBS-treated radiation chimeras died within 65 days post transplant. These data suggested that interaction of flagellin with the TLR5 expressing host gut epithelium and donor hematopoietic cells are both required for the maximum protective effect of this TLR5 agonist on GvHD in allogeneic HSCT recipients. Together our data demonstrate that peritransplant administration of flagellin effectively controls acute and chronic GvHD while preserving enhanced post-transplant donor anti-opportunistic immunity. Since flagellin has been found to be safe for use in humans as vaccine adjuvant in a number of clinical trials, the clinical use of flagellin in the setting of allogeneic HSCT is of interest. Disclosures: No relevant conflicts of interest to declare.

The Role of Bone Marrow T Cells in Regulating Hematopoietic Stem Cell Function.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2349-2349
Author(s):  
Claudia Brandao ◽  
Alexander M. de Bruin ◽  
Martijn A. Nolte
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Cd8 T Cells ◽  
Feedback Mechanism ◽  
T Cell Subsets ◽  
Effector Memory ◽  
Self Renewal ◽  
Hematopoietic Stem

Abstract Abstract 2349 After immune activation, effector/memory T cells, including virus-specific CD8 T cells, are known to migrate to the bone marrow (BM), where they can be maintained by the production of IL-15 by the stroma; however, it is not yet known whether these T cells also have a function at this site. Since depletion of T cells from allogenic BM grafts compromises HSC engraftment, we hypothesize that T cells can directly influence the balance between differentiation and self-renewal of hematopoietic stem cells (HSCs). To test the ability of T cells to affect hematopoiesis, we performed co-cultures of HSCs and T cells isolated from murine BM. We found that T cells localized in the BM are able to enhance HSC differentiation as well as their self-renewal capacity. This feature is specific for BM central memory (CM) CD8 T cells, since other T cell subsets are not able to affect HSCs to the same extent. Moreover, depletion of CM CD8 T cells from the total BM T cell pool abrogates the impact on HSC differentiation and self-renewal, indicating that this particular T cell population is both sufficient and required for the observed effects. BM CM CD8 T cells do not affect quiescence of HSCs, but do enhance their proliferative capacity, and we found that supernatant from CM CD8 T cells is sufficient for this effect. Interestingly, competitive transplantation assays showed that HSCs cultured with CM CD8 T cells-derived supernatant contribute much better to leukocyte formation than medium-treated HSCs. This effect is seen in both the myeloid and lymphoid compartment, indicating that CM CD8 T cells are able to release soluble factors that support and enhance the multilineage reconstitution capacity of HSCs. Functional studies with blocking antibodies or knock-out mice showed that the supernatant-mediated effect is not caused by the hematopoietic cytokines IL3, IL6, IL21, GM-CSF, RANTES, TNFα or IFNγ. Preliminary data indicate that this feedback mechanism of the immune system on the hematopoietic process in the bone marrow is also present in the human situation, since autologous BM T cells increase the numbers of human HSCs, as well as their differentiation capacity. Overall, these findings demonstrate that T cells have an important function in the BM and that especially CD8 TCM cells can directly influence HSC homeostasis. We postulate that this feedback mechanism of the immune system on the hematopoietic process in the BM is particularly relevant during viral infection, as the efficient migration of virus-specific CD8 T cells to the BM could well benefit the replenishment of the HSC/progenitor cell compartment and restoration of blood cell numbers that got lost upon infection. Disclosures: No relevant conflicts of interest to declare.

NKp80 defines and stimulates a reactive subset of CD8 T cells

Blood ◽  
2009 ◽  
Vol 113 (2) ◽  
pp. 358-369 ◽  
Author(s):  
Sabrina Kuttruff ◽  
Sven Koch ◽  
Alexandra Kelp ◽  
Graham Pawelec ◽  
Hans-Georg Rammensee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Natural Killer ◽  
Cd8 T Cells ◽  
Cell Subset ◽  
T Cell Responses ◽  
Effector Memory ◽  
Memory Cd8 T Cells ◽  
Cell Responses ◽  
Natural Killer Gene Complex

Abstract NKp80, an activating homodimeric C-type lectin-like receptor (CTLR), is expressed on essentially all human natural killer (NK) cells and stimulates their cytotoxicity and cytokine release. Recently, we demonstrated that the ligand for NKp80 is the myeloid-specific CTLR activation-induced C-type lectin (AICL), which is encoded in the natural killer gene complex (NKC) adjacent to NKp80. Here, we show that NKp80 also is expressed on a minor fraction of human CD8 T cells that exhibit a high responsiveness and an effector memory phenotype. Gene expression profiling and flow cytometric analyses revealed that this NKp80+ T-cell subset is characterized by the coexpression of other NK receptors and increased levels of cytotoxic effector molecules and adhesion molecules mediating access to sites of inflammation. NKp80 ligation augmented CD3-stimulated degranulation and interferon (IFN)γ secretion by effector memory T cells. Furthermore, engagement of NKp80 by AICL-expressing transfectants or macrophages markedly enhanced CD8 T-cell responses in alloreactive settings. Collectively, our data demonstrate that NKp80 is expressed on a highly responsive subset of effector memory CD8 T cells with an inflammatory NK-like phenotype and promotes T-cell responses toward AICL-expressing cells. Hence, NKp80 may enable effector memory CD8 T cells to interact functionally with cells of myeloid origin at sites of inflammation.

Prospective Molecular Identification of Alloreactive CTL Clones in Allogeneic Hematopoietic Stem Cell Transplantation.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4972-4972
Author(s):  
Christine L. O’Keefe ◽  
Ronald Sobecks ◽  
Alexander Rodriguez ◽  
Julie Curtis ◽  
Elizabeth Kuckowski ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Molecular Analysis ◽  
Cd8 T Cells ◽  
T Cell Repertoire ◽  
Cell Repertoire ◽  
Activation Markers ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Donor Cells

Abstract The process of immune recovery after allogeneic HSCT can be characterized by an often profound oligoclonality of the TCR spectrum which may reflect: 1) A decreased diversity within the T cell population or 2) Expansion of individual clones that may be caused by specific antigenic drive exerted by pathogens (e.g., CMV) or alloantigens during the process of GvHD. Novel technologies based on the molecular analysis of the TCR repertoire can be applied to study clonal responses, including multiplex amplification of rearranged TCR VB chains followed by sequencing and quantitation of their contribution to the entire T cell repertoire. We initially studied the T cell repertoire after allogeneic HSCT in sibling (N=20) and matched unrelated (N=9) transplants. VB spectratyping was performed on CD8+ T cells in 22 patients; of the expanded VB families tested, 61.2% (30 of 49) were mono- or oligoclonal by genotyping. The clonal size and structure was determined by sequencing. Immunodominant clones contributed up to 5.4% (avg. 1.4%; range 0.1–5.4%) of all CD8+ T cells, indicating that certain stimuli may drive expansion of immunodominant clones. We originally hypothesized that these expanded clones were allospecific and likely played a role in GvHD; however, we found no correlation between the presence of significant expansions and grade III/IV GvHD. Therefore, in order to identify alloreactive CTL clones and their clonotypic markers, an alternative approach was devised. The proposed technique utilizes an allostimulation step: recipient cells serve as targets to induce activation of allospecific donor cells. Donor alloreactive cells are identified by their expression of activation markers, such as CD25 or CD69. After sorting, allospecific T cells are used as a source of cDNA for identification and quantitation of allospecific clonotypes. In this fashion, we have analyzed patients undergoing allogeneic sibling and matched unrelated donor grafting (N=7). Prior to transplant, allostimulation was performed and alloreactive CD8-derived clonotypes were subjected to molecular analysis. VB families represented within alloresponsive CTL populations that were oligoclonal by genotyping were subcloned and a large number of CDR3 clones were sequenced to identify the immunodominant clonotypes. Sequences have been derived from activated CD8+ donor cells in 6 cases; an average of 4 (range 1–7) VB families per pair have been characterized.. Although the presence of multiple VB families with a diversified CDR3 spectrum suggests the polyclonal nature of alloresponsive clones, immunodominant clones were identified. A total of 13 immunodominant clonotypes have been identified in 5 patients. Five such clones were identified in one donor/recipient pair; in each pair at least one immunodominant clonotype was isolated. Up to 18 clones per VB family were sequenced, and the average expansion contributed 56% to the entire VB family (range 15–100%). Clonotype-specific primers have been designed from two expanded clones and used to detect the allospecific clones in post-transplant blood samples in one patient/donor pair. In sum, molecularly defined marker clonotypes indicative of alloresponsive CTLs in HSCT can be individually and prospectively isolated. Such clonotypes may find application in tissue and blood diagnosis of GvHD.

Bone Marrow Memory CD8 T Cells Positively Influence Hematopoietic Stem Cell Function

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3692-3692
Author(s):  
Sulima Geerman ◽  
Fernanda M Pascutti ◽  
Sudeep Bhushal ◽  
Martijn A. Nolte
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Memory T Cells ◽  
Positive Impact ◽  
Acute Infection ◽  
Activated T Cells ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Memory Cd8 T Cells

Abstract The bone marrow (BM) not only serves as a primary, but also as a secondary lymphoid organ, since it can mediate primary T cell responses against blood-borne antigens and it harbors a significant portion of the memory T cell compartment. Yet, it remains unclear to what extent BM T cells affect the local hematopoietic process. This is important from a clinical perspective, since the development of BM failure and anemia is frequently associated with (chronic) T cell-mediated inflammatory diseases, such as rheumatoid arthritis and viral infections. We postulate that particularly hematopoietic stem cells (HSCs) may be susceptible to T cell activity, since HSCs are localized in endothelial BM niches and are thus in close vicinity of where T cells enter the BM parenchyma and get activated. In support of this, we have previously shown that IFNγ, one of the key cytokines produced by activated T cells, strongly impairs HSC self-renewal and enhances their differentiation towards monoctyes, at the expense of neutrophils and erythrocytes. To examine the impact of T cells on HSC function, we performed co-culture assays and found that T cells from murine BM actually have a positive impact on HSC function, as they enhance both their differentiation and self-renewal capacity. This feature is restricted to a subset of memory CD8 T cells in the BM, since neither naïve T cells from BM nor memory CD8 T cells from the spleen showed the same effect. Correspondingly, transgenic mice with only naïve and no memory T cells have fewer HSC numbers than control mice, which can be transiently restored when memory CD8 BM T cells are injected. To test the relevance of these findings in an inflammatory setting, we infected mice with the Armstrong-strain of lymphocytic choriomeningitis virus (LCMV), which induces an acute infection that leads to a strong influx of antigen-experienced T cells in the BM. We found that LCMV-specific memory CD8 T cells isolated from BM 12 days after infection increased both the differentiation and self-renewal capacity of HSCs. Interestingly, HSCs isolated from infected mice also displayed an enhanced propensity to differentiate towards myeloid cells compared to HSCs from non-infected control mice, whereas their self-renewal capacity was not altered. To test whether chronically stimulated T cells are also able to influence HSC function, we infected mice with LCMV clone 13, which leads to a chronic infection and induces exhaustion of the virus-specific T cells. Interestingly, virus-specific T cells isolated from BM 27 days after infection, which were exhausted based on phenotype and function, did not influence HSC differentiation but they were still able to enhance the self-renewal of HSCs from non-infected control mice, although to a lesser extent than in the acute infection. These data illustrate that antigen-experienced memory CD8 T cells in BM have a positive impact on the function of HSCs. Although cytokines produced by activated T cells, such as IFNγ and TNFα, can dramatically impair HSC maintenance, it is intriguing that memory T cells can actually fulfill a positive function on the HSC compartment. We speculate that homing of memory T cells to the BM after viral infection may play an important role in restoring the damage on the hematopoietic compartment that is inflicted by the infection itself and the ensuing cytokine storm. Enhancement of such a positive feedback mechanism may be a promising new strategy for treatment of patients with BM failure. Disclosures: No relevant conflicts of interest to declare.

Developing Novel Approaches To Comprehensively Assess T Cell Repertoire Dynamics In The Early Post-Transplant Period

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4618-4618
Author(s):  
Ute E. Burkhardt ◽  
Joseph Kaplinsky ◽  
Cindy Desmarais ◽  
Kristen E. Stevenson ◽  
Edwin P. Alyea ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Healthy Controls ◽  
Transplant Recipients ◽  
Hematopoietic Stem ◽  
Post Transplant ◽  
T Cell Reconstitution ◽  
Tcr Repertoire ◽  
Control Samples

Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a highly effective treatment modality for many hematologic malignancies, a major treatment-associated toxicity is the induction of a prolonged state of T cell immunodeficiency in the transplant recipient, which in turn contributes to critical clinical outcomes such as infectious complications, and the risk of relapse. Targeted deep sequencing of the T cell receptor beta-chain (TCRβ) has emerged as a promising technology for enabling the qualitative and quantitative monitoring of T cell recovery following transplant with unprecedented resolution. Major challenges remain, however, in the establishment of informative analysis tools for characterization of global TCRβ repertoire dynamics. In the current work, we developed and applied a novel analysis approach as a mean to gain detailed biological insight into T cell reconstitution following allo-HSCT. To this end, we isolated naïve and memory CD4+ and CD8+ T cells from peripheral blood mononuclear cells of 14 patients with advanced chronic lymphocytic leukemia who underwent allo-HSCT following reduced-intensity doses of fludarabine and busulfan. From these T cell subpopulations, genomic DNA was extracted at post-transplant day 30 (d30) and later time points informative for thymic-independent (4 month post-transplant; d120) and thymic-dependent (1 year post-transplant; d365) T cell immune recovery. Subsequently, a template library for sequencing on an Illumina GA2 system was generated through PCR amplification of the TCRβ CDR3 region using an established panel of 45 Vβ- and 13 Jβ-specific primers. We obtained a median of 394,872 (range 0-26,426,784) productive reads across our 168 samples. As a comparison group, we further studied repertoire data from naïve and memory CD4+ and CD8+ T cells collected from 9 healthy adult volunteers. To characterize how transplant perturbs the TCR repertoire, we first compared VDJ usage between the transplanted patients and the healthy controls. For each of the post-transplant and control samples, we tallied the number of clones from all sequenced compartments (CD4+ and CD8+, naïve and memory) that used each of the several thousand possible VDJ combinations. We performed pairwise comparisons of the resulting VDJ distributions for all 253 sample pairs at days 30, 120 and 365 by calculating the R2 and, separately, X2 statistics. Permutation analysis demonstrated that control samples were more similar to each other than either post-transplant day 30, 120 or 365 samples (P=2.5-5.0x10-5, 2.5-5.0x10-5 and ≤2.5x10-5 by X2; 2.5-5.0x10-5, 5.5-5.7x10-4 and 1.0-1.2x10-4 by R2, respectively). Of note, whereas control samples demonstrated a similar VDJ usage, such similarity was not observed among post-transplant samples at day 30, 120 or 365 (P=0.65, 0.53, and 0.60 by X2; P=0.014, 0.38, and 0.43 by R2, respectively). These results demonstrate that VDJ usage in transplant recipients remains more heterogeneous than in healthy controls throughout the entire first year of reconstitution. To understand whether this heterogeneity reflects equilibrium or dynamic changes of the TCR repertoire, we visualized the time course of reconstitution using principal component analysis of VDJ usage. We observed marked dynamism, in which most transplant recipients both experienced a greater degree of change than was represented by the controls, and explored regions of VDJ usage very different from that of controls. Preliminarily, we observed that several transplant recipients became more similar to controls over time, while others did not. Our results demonstrate that post-transplant T cell reconstitution follows both personal and highly dynamic trajectories across a range of clinical courses, and suggest that TCR sequencing in larger sample sizes is a promising avenue for future study. Ongoing analyses focus on investigating the correlates of this dynamism among the 14 transplant recipients through subgroup analysis based on their clinical course and sequence-level analysis. The results obtained through these novel computational and systems methods will be integrated with other experimental measures of immune reconstitution including immunophenotyping and TCR excision circle (TREC) analysis. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Systemic CD8 T-Cell Memory Response to a Salmonella Pathogenicity Island 2 Effector Is Restricted to Salmonella enterica Encountered in the Gastrointestinal Mucosa

2007 ◽  
Vol 75 (6) ◽  
pp. 2708-2716 ◽  
Author(s):  
Jessica Jones-Carson ◽  
Bruce D. McCollister ◽  
Eric T. Clambey ◽  
Andrés Vázquez-Torres
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Central Memory ◽  
Effector Memory ◽  
Memory Cd8 T Cells ◽  
Memory Response ◽  
Central Memory Cells ◽  
Systemic Memory

ABSTRACT To better understand the evolution of a systemic memory response to a mucosal pathogen, we monitored antigen-specific OT1 CD8 T-cell responses to a fusion of the SspH2 protein and the peptide SIINFEKL stably expressed from the chromosome of Salmonella enterica and loaded into the class I pathway of antigen presentation of professional phagocytes through the Salmonella pathogenicity island 2 type III secretion system (TTSS). This strategy has revealed that effector memory CD8 T cells with low levels of CD62L expression (CD62Llow) are maintained in systemic sites months after vaccination in response to low-grade infections with Salmonella. However, the CD8 T-cell pool eventually declines. Low numbers of central memory cells surviving after prolonged resting from an antigen encounter can nevertheless reconstitute the systemic effector memory pool in a route-specific recall response to cognate antigens encountered in the gut. Accordingly, populations of CD62Lhigh interleukin-7 receptor-positive progenitor central memory cells grafted into naïve mice expand in response to orally administered Salmonella expressing the chromosomal translational fusion of sspH2 and the sequence encoding the SIINFEKL peptide but fail to proliferate following systemic stimulation. Moreover, populations of systemic memory CD8 T cells restricted to Salmonella in oral vaccines selectively expand in response to cognate antigens presented by cells isolated from mesenteric lymph nodes (MLN). Together, these findings have revealed the imprinting of systemic CD8 central memory T-cell recall responses against enteropathogens by MLN. MLN restriction represents a novel mechanism by which systemic CD8 T-cell immunity is confined to periods of high risk for extraintestinal dissemination.

scholarly journals Activation phenotype, rather than central– or effector–memory phenotype, predicts the recall efficacy of memory CD8+ T cells

2007 ◽  
Vol 204 (7) ◽  
pp. 1625-1636 ◽  
Author(s):  
Hirokazu Hikono ◽  
Jacob E. Kohlmeier ◽  
Shiki Takamura ◽  
Susan T. Wittmer ◽  
Alan D. Roberts ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Memory T Cells ◽  
Killer Cell ◽  
Effector Memory ◽  
Activation Markers ◽  
Memory Cd8 T Cells ◽  
And Migration ◽  
T Cell Subpopulations

The contributions of different subsets of memory CD8+ T cells to recall responses at mucosal sites of infection are poorly understood. Here, we analyzed the CD8+ T cell recall responses to respiratory virus infection in mice and demonstrate that activation markers, such as CD27 and CD43, define three distinct subpopulations of memory CD8+ T cells that differ in their capacities to mount recall responses. These subpopulations are distinct from effector– and central–memory subsets, coordinately express other markers associated with activation status, including CXCR3, CD127, and killer cell lectin-like receptor G1, and are superior to CD62L in predicting the capacity of memory T cells to mediate recall responses. Furthermore, the capacity of vaccines to elicit these memory T cell subpopulations predicted the efficacy of the recall response. These findings extend our understanding of how recall responses are generated and suggest that activation and migration markers define distinct, and unrelated, characteristics of memory T cells.

scholarly journals Significant mobilization of both conventional and regulatory T cells with AMD3100

Blood ◽  
2011 ◽  
Vol 118 (25) ◽  
pp. 6580-6590 ◽  
Author(s):  
Leslie S. Kean ◽  
Sharon Sen ◽  
Olusegun Onabajo ◽  
Karnail Singh ◽  
Jennifer Robertson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Peripheral Blood ◽  
Effector Memory ◽  
Cell Populations ◽  
Cell Repertoire ◽  
Hematopoietic Stem ◽  
Macaque Model ◽  
The Impact

AbstractIn this study, we used the rhesus macaque model to determine the impact that AMD3100 has on lymphocyte mobilization, both alone and in combination with G-CSF. Our results indicate that, unlike G-CSF, AMD3100 substantially mobilizes both B and T lymphocytes into the peripheral blood. This led to significant increases in the peripheral blood content of both effector and regulatory T-cell populations, which translated into greater accumulation of these cells in the resulting leukapheresis products. Notably, CD4+/CD25high/CD127low/FoxP3+ Tregs were efficiently mobilized with AMD3100-containing regimens, with as much as a 4.0-fold enrichment in the leukapheresis product compared with G-CSF alone. CD8+ T cells were mobilized to a greater extent than CD4+ T cells, with accumulation of 3.7 ± 0.4-fold more total CD8+ T cells and 6.2 ± 0.4-fold more CD8+ effector memory T cells in the leukapheresis product compared with G-CSF alone. Given that effector memory T-cell subpopulations may mediate less GVHD compared with other effector T-cell populations and that Tregs are protective against GVHD, our results indicate that AMD3100 may mobilize a GVHD-protective T-cell repertoire, which would be of benefit in allogeneic hematopoietic stem cell transplantation.

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