scholarly journals Engraftment of human central memory-derived effector CD8+ T cells in immunodeficient mice

Blood ◽  
2011 ◽  
Vol 117 (6) ◽  
pp. 1888-1898 ◽  
Author(s):  
Xiuli Wang ◽  
Carolina Berger ◽  
ChingLam W. Wong ◽  
Stephen J. Forman ◽  
Stanley R. Riddell ◽  
...  

Abstract In clinical trials of adoptive T-cell therapy, the persistence of transferred cells correlates with therapeutic efficacy. However, properties of human T cells that enable their persistence in vivo are poorly understood, and model systems that enable investigation of the fate of human effector T cells (TE) have not been described. Here, we analyzed the engraftment of adoptively transferred human cytomegalovirus pp65-specific CD8+ TE cells derived from purified CD45RO+CD62L+ central memory (TCM) or CD45RO+CD62L− effector memory (TEM) precursors in an immunodeficient mouse model. The engraftment of TCM-derived effector cells (TCM/E) was dependent on human interleukin-15, and superior in magnitude and duration to TEM-derived effector cells (TEM/E). T-cell receptor Vβ analysis of persisting cells demonstrated that CD8+ TCM/E engraftment was polyclonal, suggesting that the ability to engraft is a general feature of TCM/E. CD8+ TEM/E proliferated extensively after transfer but underwent rapid apoptosis. In contrast, TCM/E were less prone to apoptosis and established a persistent reservoir of functional T cells in vivo characterized by higher CD28 expression. These studies predict that human CD8+ effector T cells derived from TCM precursors may be preferred for adoptive therapy based on superior engraftment fitness.

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii111-ii111
Author(s):  
Lan Hoang-Minh ◽  
Angelie Rivera-Rodriguez ◽  
Fernanda Pohl-Guimarães ◽  
Seth Currlin ◽  
Christina Von Roemeling ◽  
...  

Abstract SIGNIFICANCE Adoptive T cell therapy (ACT) has emerged as the most effective treatment against advanced malignant melanoma, eliciting remarkable objective clinical responses in up to 75% of patients with refractory metastatic disease, including within the central nervous system. Immunologic surrogate endpoints correlating with treatment outcome have been identified in these patients, with clinical responses being dependent on the migration of transferred T cells to sites of tumor growth. OBJECTIVE We investigated the biodistribution of intravenously or intraventricularly administered T cells in a murine model of glioblastoma at whole body, organ, and cellular levels. METHODS gp100-specific T cells were isolated from the spleens of pmel DsRed transgenic C57BL/6 mice and injected intravenously or intraventricularly, after in vitro expansion and activation, in murine KR158B-Luc-gp100 glioma-bearing mice. To determine transferred T cell spatial distribution, the brain, lymph nodes, heart, lungs, spleen, liver, and kidneys of mice were processed for 3D imaging using light-sheet and multiphoton imaging. ACT T cell quantification in various organs was performed ex vivo using flow cytometry, 2D optical imaging (IVIS), and magnetic particle imaging (MPI) after ferucarbotran nanoparticle transfection of T cells. T cell biodistribution was also assessed in vivo using MPI. RESULTS Following T cell intravenous injection, the spleen, liver, and lungs accounted for more than 90% of transferred T cells; the proportion of DsRed T cells in the brains was found to be very low, hovering below 1%. In contrast, most ACT T cells persisted in the tumor-bearing brains following intraventricular injections. ACT T cells mostly concentrated at the periphery of tumor masses and in proximity to blood vessels. CONCLUSIONS The success of ACT immunotherapy for brain tumors requires optimization of delivery route, dosing regimen, and enhancement of tumor-specific lymphocyte trafficking and effector functions to achieve maximal penetration and persistence at sites of invasive tumor growth.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Lintao Liu ◽  
Enguang Bi ◽  
Xingzhe Ma ◽  
Wei Xiong ◽  
Jianfei Qian ◽  
...  

AbstractCAR-T cell therapy is effective for hematologic malignancies. However, considerable numbers of patients relapse after the treatment, partially due to poor expansion and limited persistence of CAR-T cells in vivo. Here, we demonstrate that human CAR-T cells polarized and expanded under a Th9-culture condition (T9 CAR-T) have an enhanced antitumor activity against established tumors. Compared to IL2-polarized (T1) cells, T9 CAR-T cells secrete IL9 but little IFN-γ, express central memory phenotype and lower levels of exhaustion markers, and display robust proliferative capacity. Consequently, T9 CAR-T cells mediate a greater antitumor activity than T1 CAR-T cells against established hematologic and solid tumors in vivo. After transfer, T9 CAR-T cells migrate effectively to tumors, differentiate to IFN-γ and granzyme-B secreting effector memory T cells but remain as long-lived and hyperproliferative T cells. Our findings are important for the improvement of CAR-T cell-based immunotherapy for human cancers.


2004 ◽  
Vol 78 (1) ◽  
pp. 206-215 ◽  
Author(s):  
Michael S. Seaman ◽  
Fred W. Peyerl ◽  
Shawn S. Jackson ◽  
Michelle A. Lifton ◽  
Darci A. Gorgone ◽  
...  

ABSTRACT Vaccine-elicited cytotoxic T lymphocytes (CTL) should be long-lived memory cells that can rapidly expand in number following re-exposure to antigen. The present studies were initiated to analyze the ability of plasmid interleukin-12 (IL-12) to augment CTL responses in mice when delivered during the peak phase of an immune response elicited by a plasmid human immunodeficiency virus type 1 gp120 DNA vaccine. Delivery of plasmid IL-12 on day 10 postimmunization resulted in a robust expansion of gp120-specific CD8+ T cells, as measured by tetramer, gamma interferon ELISPOT, and functional-killing assays. Interestingly, this delayed administration of plasmid IL-12 had no significant effect on antigen-specific CD4+-T-cell and antibody responses. Phenotypic analyses suggested that administration of plasmid IL-12 near the time of the peak CTL response activated and expanded antigen-specific effector cells, preventing their loss through apoptosis. However, this IL-12-augmented population of gp120-specific CD8+ T cells did not efficiently expand following gp120 boost immunization, suggesting that these effector cells would be of little utility in expanding to contain a viral infection. Analyses of the phenotypic profile and anatomic distribution of the plasmid IL-12-augmented CTL population indicated that these lymphocytes were primarily effector memory rather than central memory T cells. These observations suggest that CTL-based vaccines should elicit central memory rather than effector memory T cells and illustrate the importance of monitoring the phenotype and functionality of vaccine-induced, antigen-specific CTL.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4128-4128 ◽  
Author(s):  
Mark N. Polizzotto ◽  
Irini Sereti ◽  
Thomas S. Uldrick ◽  
Kathleen M. Wyvill ◽  
Stig M. R. Jensen ◽  
...  

Abstract Background: Despite antiretroviral therapy (ART), people with HIV continue to exhibit immune deficits including failure to fully reconstitute CD4 T cell numbers and function, resulting in increased risks of tumors and infections and reduced response to vaccination. Pomalidomide, a derivative of thalidomide (IMID), has immunomodulatory properties that may be beneficial in this setting. We explored its impact on lymphocyte number and activation in patients with and without HIV treated within a prospective clinical trial for Kaposi sarcoma. Methods: Patients received pomalidomide 5mg orally for 21 days of 28 day cycles. Assessments were performed every 4 weeks for lymphocyte numbers, Kaposi sarcoma associated herpesvirus (KSHV/HHV8) viral load (VL) and HIV VL and at 8 weeks for T cell subsets and activation by immunophenotyping of peripheral blood mononuclear cells (PBMC). KSHV VL in PBMC and HIV VL in plasma were assayed by quantitative PCR; for HIV VL we used an ultrasensitive single copy assay. Changes from baseline were evaluated using the Wilcoxon signed rank test with P<0.005 considered significant given multiple comparisons. Differences in changes between the HIV infected and uninfected groups were evaluated using the Wilcoxon rank sum test. Study registered as NCT1495598. Results: 19 patients (12 HIV infected, 7 uninfected) median age 50 years (range 32-74) were studied. All with HIV were receiving ART for median 48 months (7-227), HIV VL 1.5 copies/mL (<0.5–37), and CD4 378 cells/µl (135–752). At week 4 and 8 of therapy we observed significant increases in CD4 and CD8 counts, with a decline in CD19 B cells and no change in NK cells or HIV VL. A transient increase in KSHV VL was seen at week 4, not sustained at week 8: Abstract 4128. Table 1ParameterBaseline (cells/µl unless noted)Change to Week 4 (Med, range)PChange to Week 8 (Med, range)PCD31143 (525–2305)+264 (-419–1524)0.0028+210 (-496–1455)0.0020CD4429 (135–1171)+107 (-87–650)0.0009+86 (-37–491)0.0015CD8495 (259–1529)+108 (-271–915)0.0085+155 (-495–834)0.0046NK184 (28–557)+30 (-130–117)0.52+2 (-174–127)0.98CD19139 (9–322)-47 (-117–76)0.0039-79 (-169–62)<0.0001KSHV VL 0 copies/PBMC (0–8750)+23 (-92–5250)0.00980 (-92–20850)0.31Plasma HIV VL (infected pts)1.5 copies/mL (<0.5–37)+0.3 (-1.5–3.0)0.75+0.75 (0–28)0.13 In addition, at week 8 both CD4 and CD8 T cells showed significant increases in activation (CD38+, HLADR+ and DR+/38+) and decreases in senescence (CD57+). Both also showed a significant shift towards increased central memory (CM) and away from naive (N) and effector (E) phenotypes, with no change in effector memory (EM) cells: Abstract 4128. Table 2CD4 SubsetsBaseline (%) (med, range)Absolute Change in % at Week 8 (med, range)PRO- 27+ (N)32.6 (13.3–76.5)-6.6 (-35.8–21.6)0.002RO+ 27+ (CM)41.9 (13.6–63.6)+6.4 (-15.5–32.5)0.027RO+ 27- (EM)16.7 (4.6–31.7)+1.7 (-7.2–21.0)0.28RO- 27- (E)3.3 (0.4–14.3)-1.5 (-5.7–0.3)0.000438+34.5 (11.2–67.3)+4.3 (-13.0–19.4)0.024HLA DR+8.9 (3.3–25.0)+8.3 (0.7–19.5)<0.000138+ DR+2.5 (0.6–11.7)+2 (-1.0–8.1)<0.000157+6.3 (0.6–26.6)-1.34 (-16.2–7.6)0.034CD8 SubsetsRO- 27+ (N)21.0 (9.7–70.4)-5.1 (-13.7–14.3)0.019RO+ 27+ (CM)17.1 (2.5–37.9)+8.1 (-8.4–18.6)0.0047RO+ 27- (EM)18.4 (4.6–40.8)+1.0 (-9.4–44.9)0.35RO- 27- (E)31.8 (4.1-63.7)-6.1 (-47.3–22.5)0.0138+33.4 (8.3–66.0)+19.9 (-0.8–40.6)<0.0001HLA DR+19.6 (5.0–46.4)+11.6 (-4.7–32.1)0.000138+ DR+8.0 (0.4–33.3)+8.5 (0.1–22.6)<0.000157+30.8 (2.9–72.9)-11.0 (-28.5–6.1)<0.0001 There were no significant changes in Ki67 or PD-1 expression in either CD4 or CD8 cells. There was no significant difference between HIV infected and uninfected patient groups in the observed effects on any parameter including cell number and phenotype. Conclusions: Pomalidomide induced significant increases in the number of CD4 and CD8 T cells and the proportion of activated and central memory cells and decreased senescence in both HIV infected and uninfected subjects. Effects were not explained by alterations in HIV viremia. The transient early rise in KSHV VL may reflect reactivation of latent infection and enhance immune killing of KSHV infected cells. This analysis sheds light on possible mechanisms of IMID activity in viral-associated tumors. As the first study of immune modulation by IMIDs in vivo in people with HIV it also suggests exploration of IMIDs to augment immune responsiveness in HIV and other immunodeficiencies is warranted. Disclosures Polizzotto: Celgene Corporation: Research Funding. Off Label Use: Pomalidomide for Kaposi sarcoma. Uldrick:Celgene Corporation: Research Funding. Zeldis:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties. Yarchoan:Celgene Corporation: Research Funding.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1019-1019
Author(s):  
Xiuli Wang ◽  
Berger Carolina ◽  
Stanley R. Riddell ◽  
ChingLam W Wong ◽  
Stephen Forman ◽  
...  

Abstract Abstract 1019 Development of T cell products that have engineered specificity for CD19 has broad application to adoptive transfer therapy for B-lineage lymphoma and leukemia. Clinical studies have demonstrated the safety and feasibility of T cell transfer as a therapy for patients. But the potency of this strategy has proven challenging, primarily due to issues relating to a lack of persistence of the adoptively transferred cells in patients. The repertoire of memory T cells is heterogeneous with respect to phenotypic, functional, and epigenetic attributes. Memory T cells are divided into sub-populations of 1) effector memory (TEM) cells that distribute to tissue beds and exhibit immediate cytolytic effector functioning, and 2) central memory (TCM) cells that home to lymph nodes based on CD62L/CCR7 expression and are capable of extensive proliferative activity upon re-encountering antigen. Thus the cell-intrinsic programming of distinct memory T cell subtypes, such as TEM and TCM, likely dictate divergent fates of their derived effector cells. To address this important issue, a clear functional dichotomy between TCM- and TEM-derived CD8+ CTLs was recently delineated in a nonhuman primate model, where it was found that virus-specific CD8+ CTL clones derived from TCM, but not TEM precursors, establish persistent and functional memory following adoptive transfer. Here, we extended these studies to human effector T cells using CMV as antigen model system to investigate the engraftment of human CMVpp65-specific CD8+ effector T cells derived in vitro from either sort purified CD45RO+CD62L+ TCM or CD45RO+CD62L- TEM precursors in NOD/Scid IL-2RγCnull (NOG) mice. TCM-derived effector cells (TE(CM)) and TEM-derived effector cells (TE(EM)) were adoptively transferred (i.v) into NOG mice reconstituted with human IL-15 and T cell levels in circulation were evaluated at different time points by FACS. 20% CD8+ TE(CM) and 3% CD8+ TE(EM) were detected on day 14. Then after, engraftment of the CD8+ TE(CM) remained at a steady state of approx 2% of circulating mononuclear cells for 100 days while TE(EM) remained at or below the level of detection, indicating that TE(CM) were superior in their ability to engraft in response to IL-15 as compared to TE(EM) after adoptive transfer (P<0.05). The long-term (100 days) persisting CD8+ TE(CM), harvested from primary recipient mice were found to be capable of engrafting secondary recipients. TcR Vβ analysis of persisting cells demonstrated that CD8+ TE(CM) engraftment was polyclonal, suggesting that homeostatic engraftment fitness is a general feature of these cells. To delineate the mechanism(s) by which TE(CM) exhibit superior in vivo engraftment, TE(CM) and TE(EM) were first labeled with CFSE before in vivo administration. CFSE profiles appear that the TE(EM) proliferated more extensively than TE(CM) early after adoptive transfer as indicated by the percent of cells which diluted CFSE on day 9 (i.e., 80% vs. only 25%, respectively). However, using D2R cleavage as a measure of caspase activity as a surrogate for apoptosis, 5.8% of engrafting TE(CM) were positive for activated caspase activity compared to 31.6% of TE(EM), suggesting that in NOG mice both CD8+ TE(CM) and TE(EM) proliferate in response to IL-15 whereas TE(CM) are intrinsically resistant to caspase activation and apoptosis. We also evaluated the antigen specific responsiveness of engrafted cells. Weekly infusions of irradiated pp65+/A2+ LCL as antigen significantly augmented the levels of circulating CD8+ TE(CM) as compared to no antigen stimulation (P<0.05), whereas CD8+ TE(EM) did not respond to antigen challenge. Moreover, when CMVpp65 specific CD8+ TE(CM) or TE(EM) were infused into CMVpp65+ tumor bearing mice, tumor cells progressed in mice receiving TE(EM) at a rate similar to untreated control mice over a ten day observation period, whereas TE(CM) significantly controlled tumor progression (P<0.05), indicating that CD8+ TE(CM) but not TE(EM) are able to mediate an anti-tumor response. Together these studies confirm that human CD8+ effector T cells derived from TCM precursors are capable of persistence after infusion, can proliferate in in vivo in response to antigen, can mediate an anti-viral or anti tumor response, and are likely the preferred T cells for antigen specific anti-tumor adoptive T cell therapy . Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4805-4805
Author(s):  
Tzu-Yun Kuo ◽  
Aisha Hasan ◽  
Richard J O'Reilly

Abstract Initial clinical trials of adoptive immunotherapy have shown that the efficacy of adoptively transferred T-cells in man is often limited by the failure of cultured T cells, particularly cloned CD8 T cells, to persist in vivo. These studies demonstrated that the transferred T cells induced only transient responses and that persistence of the transferred T-cell clonotypes correlated with disease regression. A previous study suggested that CMV virus-specific CD8 T cell clones derived from central memory T cells (TCM), but not effector memory T cells (TEM), persisted long-term in non-human primates. On the other hand, another study comparing TCM and TEM derived SIV virus specific CD8 T-cell clones that were adoptively transferred in non-human primates demonstrated limited persistence of both TCM and TEM derived transferred T cells, and failed to show any difference between the two cell types. Because of these conflicting data, we have reexamed the persistence of adoptively transferred viral antigen specific T-cells derived from TCM and TEM population. Accordingly, we developed a NOG mouse model for studying the ability of human CMVpp65-specific T cells derived from central memory and effector memory populations to migrate to and accumulate in human tumor xenografts expressing CMVpp65, to alter the growth of these tumors and to persist in the tumors. This model also allows us to test immunomodulating agents and their ability to enhance targeted T-cell accumulations, antitumor activity and persistence. We analyzed CMVpp65-specific CD8 T cells derived from TCM and TEM precursors in vitro and in vivo. To tract the T-cells in vivo, we transduced membrane-bound Gaussia luciferase into TCM and TEM populations and monitored T cell trafficking by in vivo bioluminescence. Contrary to expectation, our results initially showed no differences between TCM and TEM derived CMVpp65-specific T-cell in mice co-treated with IL-2 in the time to accumulation, ultimate level of accumulation, degree of CMVpp65+ tumor regression or T-cell persistence. However, in mice cotreated with IL-15/IL-15Rα complex, both TCM and TEM exhibited more sustained engraftment and more prolonged accumulation in both the targeted tumor and in the marrow. In mice treated with IL-15/IL-15Rα, TCM and TEM derived T cells showed a similar effector memory phenotype and a similar level of regression of tumor growth. Thus, adoptive transfer of CMVpp65 specific TCM or TEM when combined with IL-15/IL-15Rα complex may support better persistence of antigen-specific T-cells following adoptive immunotherapy. Studies comparing IL-15/IL-15Rα complex with IL-15 alone are in progress. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2162-2162
Author(s):  
Martin Szyska ◽  
Stefanie Herda ◽  
Stefanie Althoff ◽  
Andreas Heimann ◽  
Tra My Dang ◽  
...  

Abstract Adoptive T cell therapy (ATT) is a promising option for the treatment of solid cancers. However, various defense mechanisms acquired by the tumor during evolution prevent transferred T cells (TC) to unfold their full potential. A combination of ATT with accessory therapeutic approaches including checkpoint inhibition and targeted therapy could lift TC inhibition and efficiently shift the immune balance towards tumor rejection. An in-vivo analysis of the impact of combination strategies on the outcome of ATT would greatly enhance the search for an optimal accessory to ATT therapy. We generated the transgenic mouse line BLITC (bioluminescence imaging of T cells) expressing an NFAT (nuclear factor of activated T cell)-dependent Click-beetle luciferase (Na et. al, 2010) and a constitutive Renilla Luciferase, allowing us to monitor migration and activation of transferred TCs in vivo. In order to analyze crucial ATT parameters in a clinically relevant tumor model, BLITC mice were crossed to the two HY-TCR transgenic mice Marilyn (CD4: H-2Ab-Dby) and MataHari (CD8: H-2Db-Uty) to generate TCs that could be monitored for in-vivo infiltration, local activation and rejection of established (> 0,5 cm x 0,5 cm / ≥10 days growth) H-Y expressing MB49 tumors. In order to better reflect the clinical situation, we lymphodepleted tumor-bearing immunocompetent albino B6 mice with fludarabine (FLu) and/or cyclophosphamide (CTX) prior to ATT. Transferred TCs were FACSorted and injected after an optional culture expansion phase. As shown before for freshly injected tumor cells (Perez-Diez, 2007), we observed a superior response of tumor-antigen specific CD4+ TCs compared to CD8+ TCs against established tumors. Whereas 5*106 CD8+ T cells hardly attenuated tumor growth, even as few as 5000 H-Y TCR-transgenic CD4+ T cells rejected tumors in most mice, depending on the lymphodepleting treatment (Figure A - remission rates in parentheses). Tumor infiltration and activation of adoptively transferred TCs was monitored in-vivo by the respective bioluminescent reporters. Around day 4 and 6, CD4+ TCs migrated from tumor-draining lymph nodes into the tumor environment and persisted until rejection. Interestingly, activation of CD4+ TCs was only transient (between days 4 and 7) in all mice, independent of therapy outcome (in Figure B shown for refractory tumor). Whereas loss of activation signal during remission was correlated with tumor clearance and decline of effector function, in refractory tumors it suggests a rapid inactivation of infiltrating TCs by the tumor microenvironment. Our data indicate that the failure of tumor rejection is not caused by impaired peripheral expansion or tumor homing but rather by inhibition of TC effector function. Responsible mechanisms and counter-acting therapeutic interventions are the focus of ongoing studies. In summary, the BLITC reporter system facilitates analysis of therapeutic parameters for ATT in a well-established solid tumor model. Using BLITC mice for transduction with TCR or CAR expression cassettes could allow rapid monitoring of on-target as well as undesired off-target effects in virtually any tumor setting. Future experiments will focus on the beneficial effects of combination treatments on the activation of adoptively transferred TCs. Figure. Figure. Disclosures No relevant conflicts of interest to declare.


2015 ◽  
Vol 112 (24) ◽  
pp. 7551-7556 ◽  
Author(s):  
Bettina Weigelin ◽  
Elixabet Bolaños ◽  
Alvaro Teijeira ◽  
Ivan Martinez-Forero ◽  
Sara Labiano ◽  
...  

Cancer immunotherapy is undergoing significant progress due to recent clinical successes by refined adoptive T-cell transfer and immunostimulatory monoclonal Ab (mAbs). B16F10-derived OVA-expressing mouse melanomas resist curative immunotherapy with either adoptive transfer of activated anti-OVA OT1 CTLs or agonist anti-CD137 (4-1BB) mAb. However, when acting in synergistic combination, these treatments consistently achieve tumor eradication. Tumor-infiltrating lymphocytes that accomplish tumor rejection exhibit enhanced effector functions in both transferred OT-1 and endogenous cytotoxic T lymphocytes (CTLs). This is consistent with higher levels of expression of eomesodermin in transferred and endogenous CTLs and with intravital live-cell two-photon microscopy evidence for more efficacious CTL-mediated tumor cell killing. Anti-CD137 mAb treatment resulted in prolonged intratumor persistence of the OT1 CTL-effector cells and improved function with focused and confined interaction kinetics of OT-1 CTL with target cells and increased apoptosis induction lasting up to six days postadoptive transfer. The synergy of adoptive T-cell therapy and agonist anti-CD137 mAb thus results from in vivo enhancement and sustainment of effector functions.


Blood ◽  
2005 ◽  
Vol 105 (1) ◽  
pp. 241-250 ◽  
Author(s):  
Daniel J. Powell ◽  
Mark E. Dudley ◽  
Paul F. Robbins ◽  
Steven A. Rosenberg

Abstract In humans, the pathways of memory T-cell differentiation remain poorly defined. Recently, adoptive cell transfer (ACT) of tumor-reactive T lymphocytes to metastatic melanoma patients after nonmyeloablative chemotherapy has resulted in persistence of functional, tumor-reactive lymphocytes, regression of disease, and induction of melanocyte-directed autoimmunity in some responding patients. In the current study, longitudinal phenotypic analysis was performed on melanoma antigen-specific CD8+ T cells during their transition from in vitro cultured effector cells to long-term persistent memory cells following ACT to 6 responding patients. Tumor-reactive T cells used for therapy were generally late-stage effector cells with a CD27Lo CD28Lo CD45RA- CD62 ligand- (CD62L-) CC chemokine receptor 7- (CCR7-) interleukin-7 receptor αLo (IL-7RαLo) phenotype. After transfer, rapid up-regulation and continued expression of IL-7Rα in vivo suggested an important role for IL-7R in immediate and long-term T-cell survival. Although the tumor antigen-specific T-cell population contracted between 1 and 4 weeks after transfer, stable numbers of CD27+ CD28+ tumor-reactive T cells were maintained, demonstrating their contribution to the development of long-term, melanoma-reactive memory CD8+ T cells in vivo. At 2 months after transfer, melanoma-reactive T cells persisted at high levels and displayed an effector memory phenotype, including a CD27+ CD28+ CD62L- CCR7- profile, which may explain in part their ability to mediate tumor destruction. (Blood. 2005;105:241-250)


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