1
|
Koller P, Baran N, Harutyunyan K, Cavazos A, Mallampati S, Chin RL, Jiang Z, Sun X, Lee HH, Hsu JL, Williams P, Huang X, Curran MA, Hung MC, Konopleva M. PD-1 blockade in combination with dasatinib potentiates induction of anti-acute lymphocytic leukemia immunity. J Immunother Cancer 2023; 11:e006619. [PMID: 37793852 PMCID: PMC10551962 DOI: 10.1136/jitc-2022-006619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2023] [Indexed: 10/06/2023] Open
Abstract
Immunotherapy, in the form of hematopoietic stem cell transplantation (HSCT), has been part of the standard of care in the treatment of acute leukemia for over 40 years. Trials evaluating novel immunotherapeutic approaches, such as targeting the programmed death-1 (PD-1) pathway, have unfortunately not yielded comparable results to those seen in solid tumors. Major histocompatibility complex (MHC) proteins are cell surface proteins essential for the adaptive immune system to recognize self versus non-self. MHC typing is used to determine donor compatibility when evaluating patients for HSCT. Recently, loss of MHC class II (MHC II) was shown to be a mechanism of immune escape in patients with acute myeloid leukemia after HSCT. Here we report that treatment with the tyrosine kinase inhibitor, dasatinib, and an anti-PD-1 antibody in preclinical models of Philadelphia chromosome positive B-cell acute lymphoblastic leukemia is highly active. The dasatinib and anti-PD-1 combination reduces tumor burden, is efficacious, and extends survival. Mechanistically, we found that treatment with dasatinib significantly increased MHC II expression on the surface of antigen-presenting cells (APC) in a tumor microenvironment-independent fashion and caused influx of APC cells into the leukemic bone marrow. Finally, the induction of MHC II may potentiate immune memory by impairing leukemic engraftment in mice previously cured with dasatinib, after re-inoculation of leukemia cells. In summary, our data suggests that anti-PD-1 therapy may enhance the killing ability of dasatinib via dasatinib driven APC growth and expansion and upregulation of MHC II expression, leading to antileukemic immune rewiring.
Collapse
Affiliation(s)
- Paul Koller
- Hematology, City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Natalia Baran
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Karine Harutyunyan
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Antonio Cavazos
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Saradhi Mallampati
- Department of Hematopathology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Renee L Chin
- Cancer Systems Imaging, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Zhou Jiang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Xian Sun
- Department of Medical Oncology, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Heng-Huan Lee
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jennifer L Hsu
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | | | - Xuelin Huang
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Michael A Curran
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Mien-Chie Hung
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate Institute of Biomedical Sciences, Research Center for Cancer Biology, and Center for Molecular Medicine, China Medical University, Taichung, Taiwan
| | - Marina Konopleva
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Medicine (Oncology) and Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| |
Collapse
|
2
|
Raghuvanshi R, Bharate SB. Recent Developments in the Use of Kinase Inhibitors for Management of Viral Infections. J Med Chem 2021; 65:893-921. [PMID: 33539089 DOI: 10.1021/acs.jmedchem.0c01467] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Kinases are a group of therapeutic targets involved in the progression of numerous diseases, including cancer, rheumatoid arthritis, Alzheimer's disease, and viral infections. The majority of approved antiviral agents are inhibitors of virus-specific targets that are encoded by individual viruses. These inhibitors are narrow-spectrum agents that can cause resistance development. Viruses are dependent on host cellular proteins, including kinases, for progression of their life-cycle. Thus, targeting kinases is an important therapeutic approach to discovering broad-spectrum antiviral agents. As there are a large number of FDA approved kinase inhibitors for various indications, their repurposing for viral infections is an attractive and time-sparing strategy. Many kinase inhibitors, including baricitinib, ruxolitinib, imatinib, tofacitinib, pacritinib, zanubrutinib, and ibrutinib, are under clinical investigation for COVID-19. Herein, we discuss FDA approved kinase inhibitors, along with a repertoire of clinical/preclinical stage kinase inhibitors that possess antiviral activity or are useful in the management of viral infections.
Collapse
Affiliation(s)
- Rinky Raghuvanshi
- Medicinal Chemistry Division,CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India.,Academy of Scientific & Innovative Research, Ghaziabad 201002, India
| | - Sandip B Bharate
- Medicinal Chemistry Division,CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India.,Academy of Scientific & Innovative Research, Ghaziabad 201002, India
| |
Collapse
|
3
|
Fox KA, Kirwan DE, Whittington AM, Krishnan N, Robertson BD, Gilman RH, López JW, Singh S, Porter JC, Friedland JS. Platelets Regulate Pulmonary Inflammation and Tissue Destruction in Tuberculosis. Am J Respir Crit Care Med 2019; 198:245-255. [PMID: 29420060 DOI: 10.1164/rccm.201710-2102oc] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
RATIONALE Platelets may interact with the immune system in tuberculosis (TB) to regulate human inflammatory responses that lead to morbidity and spread of infection. OBJECTIVES To identify a functional role of platelets in the innate inflammatory and matrix-degrading response in TB. METHODS Markers of platelet activation were examined in plasma from 50 patients with TB before treatment and 50 control subjects. Twenty-five patients were followed longitudinally. Platelet-monocyte interactions were studied in a coculture model infected with live, virulent Mycobacterium tuberculosis (M.tb) and dissected using qRT-PCR, Luminex multiplex arrays, matrix degradation assays, and colony counts. Immunohistochemistry detected CD41 (cluster of differentiation 41) expression in a pulmonary TB murine model, and secreted platelet factors were measured in BAL fluid from 15 patients with TB and matched control subjects. MEASUREMENTS AND MAIN RESULTS Five of six platelet-associated mediators were upregulated in plasma of patients with TB compared with control subjects, with concentrations returning to baseline by Day 60 of treatment. Gene expression of the monocyte collagenase MMP-1 (matrix metalloproteinase-1) was upregulated by platelets in M.tb infection. Platelets also enhanced M.tb-induced MMP-1 and -10 secretion, which drove type I collagen degradation. Platelets increased monocyte IL-1 and IL-10 and decreased IL-12 and MDC (monocyte-derived chemokine; also known as CCL-22) secretion, as consistent with an M2 monocyte phenotype. Monocyte killing of intracellular M.tb was decreased. In the lung, platelets were detected in a TB mouse model, and secreted platelet mediators were upregulated in human BAL fluid and correlated with MMP and IL-1β concentrations. CONCLUSIONS Platelets drive a proinflammatory, tissue-degrading phenotype in TB.
Collapse
Affiliation(s)
- Katharine A Fox
- 1 Infectious Diseases and Immunity, Wellcome Trust Centre for Global Health Research, and
| | - Daniela E Kirwan
- 1 Infectious Diseases and Immunity, Wellcome Trust Centre for Global Health Research, and
| | - Ashley M Whittington
- 1 Infectious Diseases and Immunity, Wellcome Trust Centre for Global Health Research, and
| | - Nitya Krishnan
- 2 Medical Research Council Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, United Kingdom
| | - Brian D Robertson
- 2 Medical Research Council Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, United Kingdom
| | - Robert H Gilman
- 3 Department of International Health, Johns Hopkins University, Baltimore Maryland.,4 Laboratorio de Investigación en Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - José W López
- 5 Laboratorio de Bioinformática y Biología Molecular, Universidad Peruana Cayetano Heredia, Lima, Peru.,6 Instituto Nacional de Salud del Niño, Lima, Peru; and
| | - Shivani Singh
- 1 Infectious Diseases and Immunity, Wellcome Trust Centre for Global Health Research, and
| | - Joanna C Porter
- 7 Centre for Inflammation and Tissue Repair, Respiratory Medicine, University College London, United Kingdom
| | - Jon S Friedland
- 1 Infectious Diseases and Immunity, Wellcome Trust Centre for Global Health Research, and
| |
Collapse
|
4
|
Li J, Aipire A, Zhao H, Yuan P, Li J. Pleurotus ferulae polysaccharides improve the antitumor efficacy of therapeutic human papillomavirus dendritic cell-based vaccine. Hum Vaccin Immunother 2018; 15:611-619. [PMID: 30427754 DOI: 10.1080/21645515.2018.1547604] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We previously found that Pleurotus ferulae polysaccharides (PFPS) improved the maturation and function of dendritic cells (DCs). In this study, we investigated the effects of PFPS on the antitumor efficacy of therapeutic human papillomavirus (HPV) DC-based vaccine. PFPS stimulated DCs pulsed with HPV E6/E7 peptides were used to treat tumor mice on day 5 & 12 (HPV + PFPS-DCs early) and day 12 & 19 (HPV + PFPS-DCs late) after TC-1 cell injection. Compared to control group, both HPV + PFPS-DCs early and HPV + PFPS-DCs late strategies significantly inhibited tumor growth, which was significantly correlated with the increased activation status of both CD4+ and CD8+ T cells, the decreased frequencies of myeloid-derived suppressor cells, and the induction of HPV-specific CD8+ T cell responses. The survival of tumor mice was also greatly improved by HPV + PFPS-DCs early. Moreover, HPV + PFPS-DCs early completely inhibited the growth of second challenged TC-1 cells in tumor free mice. The results showed that PFPS improved the antitumor efficacy of therapeutic HPV DC-based vaccine, suggesting that PFPS might be a potential adjuvant for DC-based vaccines. This study provides a potential strategy for developing the therapeutic DC-based vaccine against cervical cancer.
Collapse
Affiliation(s)
- Jinyu Li
- a College of Life Science , Xinjiang Normal University , Urumqi , Xinjiang , China
| | - Adila Aipire
- b Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology , Xinjiang University , Urumqi , Xinjiang , China
| | - Huixin Zhao
- a College of Life Science , Xinjiang Normal University , Urumqi , Xinjiang , China
| | - Pengfei Yuan
- b Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology , Xinjiang University , Urumqi , Xinjiang , China
| | - Jinyao Li
- b Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology , Xinjiang University , Urumqi , Xinjiang , China
| |
Collapse
|
5
|
Xiao W, Ibrahim ML, Redd PS, Klement JD, Lu C, Yang D, Savage NM, Liu K. Loss of Fas Expression and Function Is Coupled with Colon Cancer Resistance to Immune Checkpoint Inhibitor Immunotherapy. Mol Cancer Res 2018; 17:420-430. [PMID: 30429213 DOI: 10.1158/1541-7786.mcr-18-0455] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/09/2018] [Accepted: 11/07/2018] [Indexed: 12/28/2022]
Abstract
Despite the remarkable efficacy of immune checkpoint inhibitor (ICI) immunotherapy in various types of human cancers, colon cancer, except for the approximately 4% microsatellite-instable (MSI) colon cancer, does not respond to ICI immunotherapy. ICI acts through activating CTLs that use the Fas-FasL pathway as one of the two effector mechanisms to suppress tumor. Cancer stem cells are often associated with resistance to therapy including immunotherapy, but the functions of Fas in colon cancer apoptosis and colon cancer stem cells are currently conflicting and highly debated. We report here that decreased Fas expression is coupled with a subset of CD133+CD24lo colon cancer cells in vitro and in vivo. Consistent of the lower Fas expression level, this subset of CD133+CD24loFaslo colon cancer cells exhibits decreased sensitivity to FasL-induced apoptosis. Furthermore, FasL selectively enriches CD133+CD24loFaslo colon cancer cells. CD133+CD24loFaslo colon cancer cells exhibit increased lung colonization potential in experimental metastatic mouse models and decreased sensitivity to tumor-specific CTL adoptive transfer and ICI immunotherapies. Interestingly, FasL challenge selectively enriched this subset of colon cancer cells in microsatellite-stable (MSS) but not in the MSI human colon cancer cell lines. Consistent with the downregulation of Fas expression in CD133+CD24lo cells, lower Fas expression level is significantly correlated with decreased survival in patients with human colon cancer. IMPLICATIONS: Our data determine that CD133+CD24loFaslo colon cancer cells are capable to evade Fas-FasL cytotoxicity of tumor-reactive CTLs and targeting this subset of colon cancer cells is potentially an effective approach to suppress colon cancer immune evasion.
Collapse
Affiliation(s)
- Wei Xiao
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia
| | - Mohammed L Ibrahim
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia.,Georgia Cancer Center, Medical College of Georgia, Augusta, Georgia
| | - Priscilla S Redd
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia.,Georgia Cancer Center, Medical College of Georgia, Augusta, Georgia.,Charlie Norwood VA Medical Center, Augusta, Georgia
| | - John D Klement
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia.,Georgia Cancer Center, Medical College of Georgia, Augusta, Georgia.,Charlie Norwood VA Medical Center, Augusta, Georgia
| | - Chunwan Lu
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia.,Georgia Cancer Center, Medical College of Georgia, Augusta, Georgia.,Charlie Norwood VA Medical Center, Augusta, Georgia
| | - Dafeng Yang
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia.,Charlie Norwood VA Medical Center, Augusta, Georgia
| | - Natasha M Savage
- Department of Pathology, Medical College of Georgia, Augusta, Georgia
| | - Kebin Liu
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia. .,Georgia Cancer Center, Medical College of Georgia, Augusta, Georgia.,Charlie Norwood VA Medical Center, Augusta, Georgia
| |
Collapse
|
6
|
Nygaard HB. Targeting Fyn Kinase in Alzheimer's Disease. Biol Psychiatry 2018; 83:369-376. [PMID: 28709498 PMCID: PMC5729051 DOI: 10.1016/j.biopsych.2017.06.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/02/2017] [Accepted: 06/05/2017] [Indexed: 01/06/2023]
Abstract
The past decade has brought tremendous progress in unraveling the pathophysiology of Alzheimer's disease (AD). While increasingly sophisticated immunotherapy targeting soluble and aggregated brain amyloid-beta (Aβ) continues to dominate clinical research in AD, a deeper understanding of Aβ physiology has led to the recognition of distinct neuronal signaling pathways linking Aβ to synaptotoxicity and neurodegeneration and to new targets for therapeutic intervention. Identifying specific signaling pathways involving Aβ has allowed for the development of more precise therapeutic interventions targeting the most relevant molecular mechanisms leading to AD. In this review, I highlight the discovery of cellular prion protein as a high-affinity receptor for Aβ oligomers, and the downstream signaling pathway elucidated to date, converging on nonreceptor tyrosine kinase Fyn. I discuss preclinical studies targeting Fyn as a therapeutic intervention in AD and our recent experience with the safety, tolerability, and cerebrospinal fluid penetration of the Src family kinase inhibitor saracatinib in patients with AD. Fyn is an attractive target for AD therapeutics, not only based on its activation by Aβ via cellular prion protein but also due to its known interaction with tau, uniquely linking the two key pathologies in AD. Fyn is also a challenging target, with broad expression throughout the body and significant homology with other members of the Src family kinases, which may lead to unintended off-target effects. A phase 2a proof-of-concept clinical trial in patients with AD is currently under way, providing critical first data on the potential effectiveness of targeting Fyn in AD.
Collapse
Affiliation(s)
- Haakon B. Nygaard
- Assistant Professor of Medicine (Neurology), University of British Columbia, Department of Medicine, Division of Neurology, Djavad Mowafaghian Centre for Brain Health, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| |
Collapse
|
7
|
Li J, Valentin A, Beach RK, Alicea C, Felber BK, Pavlakis GN. DNA is an efficient booster of dendritic cell-based vaccine. Hum Vaccin Immunother 2016; 11:1927-35. [PMID: 26125100 PMCID: PMC4635890 DOI: 10.1080/21645515.2015.1020265] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
DC-based therapeutic vaccines as a promising strategy against chronic infections and cancer have been validated in several clinical trials. However, DC-based vaccines are complex and require many in vitro manipulations, which makes this a personalized and expensive therapeutic approach. In contrast, DNA-based vaccines have many practical advantages including simplicity, low cost of manufacturing and potent immunogenicity already proven in non-human primates and humans. In this study, we explored whether DC-based vaccines can be simplified by the addition of plasmid DNA as prime or boost to achieve robust CD8-mediated immune responses. We compared the cellular immunity induced in BALB/c and C57BL/6 mice by DC vaccines, loaded either with peptides or optimized SIV Env DNA, and plasmid DNA-based vaccines delivered by electroporation (EP). We found that mature DC loaded with peptides (P-mDC) induced the highest CD8(+) T cell responses in both strains of mice, but those responses were significantly higher in the C57BL/6 model. A heterologous prime-boost strategy (P-DC prime-DNA boost) induced CD8(+) T cell responses similar to those obtained by the P-DC vaccine. Importantly, this strategy elicited robust polyfunctional T cells as well as highest antigen-specific central memory CD8+ T cells in C57BL/6 mice, suggesting long-term memory responses. These results indicate that a DC-based vaccine in combination with DNA in a heterologous DC prime-DNA boost strategy has potential as a repeatedly administered vaccine.
Collapse
Affiliation(s)
- Jinyao Li
- a Human Retrovirus Section; Vaccine Branch; Center for Cancer Research; National Cancer Institute ; Frederick , MD USA
| | | | | | | | | | | |
Collapse
|
8
|
Takai S, Schlom J, Tucker J, Tsang KY, Greiner JW. Inhibition of TGF-β1 signaling promotes central memory T cell differentiation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 191:2299-307. [PMID: 23904158 PMCID: PMC3889640 DOI: 10.4049/jimmunol.1300472] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
This study affirmed that isolated CD8(+) T cells express mRNA and produce TGF-β following cognate peptide recognition. Blockage of endogenous TGF-β with either a TGF-β-blocking Ab or a small molecule inhibitor of TGF-βRI enhances the generation of CD62L(high)/CD44(high) central memory CD8(+) T cells accompanied with a robust recall response. Interestingly, the augmentation within the central memory T cell pool occurs in lieu of cellular proliferation or activation, but with the expected increase in the ratio of the Eomesoderm/T-bet transcriptional factors. Yet, the signal transduction pathway(s) seems to be noncanonical, independent of SMAD or mammalian target of rapamycin signaling. Enhancement of central memory generation by TGF-β blockade is also confirmed in human PBMCs. The findings underscore the role(s) that autocrine TGF-β plays in T cell homeostasis and, in particular, the balance of effector/memory and central/memory T cells. These results may provide a rationale to targeting TGF-β signaling to enhance Ag-specific CD8(+) T cell memory against a lethal infection or cancer.
Collapse
Affiliation(s)
- Shinji Takai
- Laboratory of Tumor Immunology and Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
9
|
Vasconcelos JR, Dominguez MR, Araújo AF, Ersching J, Tararam CA, Bruna-Romero O, Rodrigues MM. Relevance of long-lived CD8(+) T effector memory cells for protective immunity elicited by heterologous prime-boost vaccination. Front Immunol 2012; 3:358. [PMID: 23264773 PMCID: PMC3525016 DOI: 10.3389/fimmu.2012.00358] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 11/10/2012] [Indexed: 11/13/2022] Open
Abstract
Owing to the importance of major histocompatibility complex class Ia-restricted CD8(+) T cells for host survival following viral, bacterial, fungal, or parasitic infection, it has become largely accepted that these cells should be considered in the design of a new generation of vaccines. For the past 20 years, solid evidence has been provided that the heterologous prime-boost regimen achieves the best results in terms of induction of long-lived protective CD8(+) T cells against a variety of experimental infections. Although this regimen has often been used experimentally, as is the case for many vaccines, the mechanism behind the efficacy of this vaccination regimen is still largely unknown. The main purpose of this review is to examine the characteristics of the protective CD8(+) T cells generated by this vaccination regimen. Part of its efficacy certainly relies on the generation and maintenance of large numbers of specific lymphocytes. Other specific characteristics may also be important, and studies on this direction have only recently been initiated. So far, the characterization of these protective, long-lived T cell populations suggests that there is a high frequency of polyfunctional T cells; these cells cover a large breadth and display a T effector memory (TEM) phenotype. These TEM cells are capable of proliferating after an infectious challenge and are highly refractory to apoptosis due to a control of the expression of pro-apoptotic receptors such as CD95. Also, they do not undergo significant long-term immunological erosion. Understanding the mechanisms that control the generation and maintenance of the protective activity of these long-lived TEM cells will certainly provide important insights into the physiology of CD8(+) T cells and pave the way for the design of new or improved vaccines.
Collapse
Affiliation(s)
- José R Vasconcelos
- Centro de Terapia Celular e Molecular, Universidade Federal de São Paulo - Escola Paulista de Medicina São Paulo, São Paulo, Brazil ; Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo - Escola Paulista de Medicina São Paulo, São Paulo, Brazil
| | | | | | | | | | | | | |
Collapse
|