Generation of peptide-specific CD8+ T cells by phytohemagglutinin-stimulated antigen-mRNA-transduced CD4+ T cells

Functional analysis of antigen-specific CD8(+) T cells is important for understanding the immune response in various immunological disorders. To analyze CD8(+) T cell responses to a variety of antigens with no readily defined peptides available, we developed a system using CD4(+) phytohemagglutinin (PHA) blasts transduced with mRNA for antigen molecules. CD4(+) PHA blasts express MHC class I and II, and also CD80 and CD86 and are thus expected to serve as potent antigen presenting cells. EGFP mRNA could be transduced into and the protein expressed by more than 90% of either LCL or CD4(+) PHA blasts. Its expression stably persisted for more than 2 weeks after transduction. In experiments with HLA-A*2402 restricted CD8(+) CTL clones for either EBNA3A or a cancer-testis antigen, SAGE, mRNA-transduced lymphoid cells were appropriate target cells in ELISPOT assays or (51)Cr releasing assays. Finally, using CD4(+) PHA blasts transduced with mRNA of a cancer-testis antigen MAGE-A4, we successfully generated specific CTL clones that recognized a novel HLA-B*4002 restricted epitope, MAGE-A4(223-231). Messenger RNA-transduced CD4(+) PHA blasts are thus useful antigen presenting cells for analysis of CD8(+) T cell responses and induction of specific T cells for potential immunotherapy.     

CD3+CD4-CD8- alphabeta-TCR+ T cell as immune regulatory cell

Down-regulation of immune responses by regulatory T cells is one of the major mechanisms involved in the induction of tolerance to self- and alloantigens as demonstrated in a number of models of transplantation and autoimmunity. It is clear that regulatory T cells consist of different subsets. Recently a novel subset of antigen-specific alphabeta-TCR+ CD4-CD8- (double negative, DN) regulatory T cells has been found to be able to inhibit the function of the CD8+ T cells carrying the same T cell receptor specificity and prevent the rejection of skin allografts. Identification of the DN regulatory T cells and their novel mechanism of suppression can help us to understand how donor-specific transplantation tolerance can be achieved and to explain how tolerance to self-antigens can be maintained in the periphery.     

A novel peripheral CD4+CD8+ T cell population: Inheritance of CD8α expression on CD4+ T cells

In this study we show the inheritance of a CD4⁺CD8⁺ peripheral T cell population in the H.B15 chicken strain. A large proportion of αβ T cells in peripheral blood (20–40%), spleen (10–20%) and intestinal epithelium (5–10%) co-express CD4 and CD8α, but not CD8β. CD4⁺ CD8αα cells are functionally normal T cells, since they proliferate in response to mitogens and signals delivered via the αβT cell receptor as well as via the CD28 co-receptor. These cells induce in vivo a graft versus host-reaction, providing further evidence for their function as CD4⁺ T cells. The CD4⁺CD8αα T cell population was found in 75% of the first progeny and in 100% of further progenies, demonstrating that co-expression of CD4 and CD8 on peripheral T cells is an inherited phenomenon. In addition, cross-breeding data suggest a dominant Mendelian form of inheritance. The hereditary expression of CD8α on peripheral CD4⁺ T cells in chicken provides a unique model in which to study the regulation of CD4 and CD8 expression.     

'Radioresistant' CD4-CD8- intrathymic T cell precursors differentiate into mature CD4+CD8- and CD4-CD8+ T cells. Development of 'radioresistant' CD4-CD8- intrathymic T cell precursors

Using lectin (PNA) and monoclonal antibodies for Pgp-1, IL-2R, H-2k, CD3, and F23.1 (T cell receptor V beta 8), we characterized the 'radioresistant' CD4-CD8- double negative thymocytes at an early stage after 800 rad irradiation. Most of the CD4-CD8- cells on day 8 after irradiation expressed a high level of Thy-1, H-2k, and PNA, while a small proportion of these cells were CD3+ and/or F23.1+. The appearance of Pgp-1 and IL-2R on the 'radioresistant' double negative precursors was also sequentially examined from day 5 to day 9 after irradiation. The double negative thymocytes at day 5 expressed the highest level of Pgp-1 antigens and these cells gradually decreased in number from day 7 to day 9. By contrast, IL-2R was transiently expressed on the double negative cells on the day 7 and 8 after irradiation. These results indicate that progression of thymocyte development occurred within the CD4-CD8- thymocytes after irradiation. We further examined the homing ability of the double negative 'radioresistant' intrathymic T cell precursors to the periphery by intrathymic cell transplantation method. The double negative thymocytes proliferate and differentiate into CD4+CD8+ cells and CD4+CD8- cells but few CD4-CD8+ cells in the thymus, while only CD4-CD8+ cells were detected in the peripheral lymphoid organs 14 days after intrathymic transplantation of the double negative cells in the H-2 compatible Thy-1 congenic mice. These results suggest that the 'radioresistant' intrathymic precursors differentiate and mature in the thymus and migrate to the periphery.     

Contributions of CD4+, CD8+, and CD4+CD8+ T cells to skewing within the peripheral T cell receptor beta chain repertoire of healthy macaques.

Diversity in the peripheral T cell receptor repertoire of rhesus (Macaca mulatta) and pig-tailed macaques (Macaca nemestrina) has been studied by examining the profile of CDR3 lengths in TCR beta chains. Expressed CDR3 length distribution profiles for individual TCRBV families were obtained from total peripheral blood mononuclear cells (PBMC) and T cell subsets isolated from PBMC. These studies reveal that the T cell receptor repertoire of PBMC from healthy macaques often exhibits skewing in TCRBV family CDR3 profiles. The skewing of TCRBV family CDR3 profiles was evident as discrete expanded length(s) and was detected in up to 50% of the PBMC profiles. Analyses of separated T cell populations demonstrated that the CD8+ T cell subset was responsible for the majority of observed skewing in CDR3 length profiles. However, CD4+ T cells were also shown to contribute to the skewed peripheral PBMC repertoire in these animals. While certain TCRBV families frequently displayed skewed profiles, there was no concordance in the particular CDR3 lengths expanded among the different animals. Furthermore, an additional feature of the peripheral blood of the animals studied was the presence of an unusual population of extrathymic CD4 and CD8+ (double-positive) T cells (up to 9.6% in the PBMC of rhesus macaques). The double-positive T cells could be differentiated from CD4 single-positive and CD8 single-positive T cells by their increased surface expression of LFA-1 and decreased CD62L expression. The percentage of the double-positive T cells was higher in rhesus than pig-tailed macaques and contributed substantially to the peripheral T cell repertoire.     

A CD3- subset of CD4-8+ thymocytes: a rapidly cycling intermediate in the generation of CD4+8+ cells

T lymphocytes with the surface phenotype CD4+8- and CD4-8+ are considered to be representative of functionally mature cells. We show here that adult murine thymus contains a subpopulation of CD4-8+ cells that differ from CD4-8+ cells found in the periphery in that they do not express the T cell receptor-associated CD3 molecular complex. Such CD3-4-8+ thymocytes are cortisone sensitive and rapidly cycling in situ. Furthermore, in contrast to mature T cells, most CD3-4-8+ thymocytes express low levels of CD5 and high levels of the B2A2 antigen. CD3-4-8+ thymocytes fail to respond to a variety of mitogenic stimuli in vitro but do give rise upon short-term culture to CD4+8+ cells. It is suggested that CD3-4-8+ thymocytes represent a transitional stage of thymus differentiation between the CD4-8- and CD4+8+ compartments.     

A novel CD3-J11d+ subset of CD4+CD8- cells repopulating thymus in radiation bone marrow chimeras

Sequential appearance of T cell subpopulations occurs in the thymus of irradiated AKR (H-2k, Thy-1.1) mice at an early stage after transplantation with bone marrow cells of C3H/HeN (H-2k, Thy-1.2) mice. The donor-derived thymocytes were first detected on day 8 after bone marrow reconstitution. Although most of the thymocytes were CD4-CD8- cells, an appreciable level of CD4+CD8- cells was detected in the thymus at this stage. The early appearing CD4+CD8- cells were a novel subset of thymocytes that were J11d+CD3-. From day 10 to day 21 the proportion of CD4+CD8-CD3-J11d+ cells decreased while the proportion of CD4+CD8+ cells and CD4+CD8-CD3+J11d- cells increased. The CD4+CD8-CD3- cells seem to diversify to form CD4+CD8+ thymocytes after short-term culture in vitro. These results suggested the existence of a differential pathway from CD4-CD8- cells to CD4+CD8+ cells via CD4+CD8- cells in thymus.     

Generation and characterization of antigen-specific CD4+, CD8+, and CD4+CD8+ T-cell clones from patients with carbamazepine hypersensitivity

BACKGROUND: Hypersensitivity is a serious manifestation of anticonvulsant therapy characterized by infiltration of the epidermis and dermis by activated CD8(+) and CD4(+) T-cells, respectively. Attempts to characterize drug-specific CD8(+) T cells have been largely unsuccessful. OBJECTIVES: The aim of these studies was to generate and characterize CD4(+), CD8(+), and CD4(+)CD8(+) T cells in patients with carbamazepine hypersensitivity. METHODS: Carbamazepine-specific T-cell clones were generated from 5 patients by using modified cloning methodologies. Cell surface receptor phenotype, functionality, and mechanisms of antigen presentation were then compared. RESULTS: Ninety CD4(+), 23 CD8(+), and 14 CD4(+)CD8(+) carbamazepine-specific T-cell clones were generated. CD4(+) T-cell clones proliferated vigorously with carbamazepine associated with MHC class II but exhibited little cytotoxic activity. In contrast, most CD8(+) T cells proliferated weakly but effectively killed target cells via an MHC class I or MHC class II restricted, perforin-dependent pathway. CD4(+)CD8(+) T cells displayed characteristics similar to those of CD4(+) T cells; however, drug stimulation was demonstrable in the absence of antigen-presenting cells. Carbamazepine was presented to CD4(+), CD8(+), and CD4(+)CD8(+) T cells in the absence of antigen processing. Drug stimulation resulted in the secretion of IFN-gamma and IL-5. A panel of CD11a(+)CD27(-) clones differentially expressed the receptors CXCR4, CCR4, CCR5, CCR8, CCR9, and CCR10. CONCLUSION: Carbamazepine-specific CD4(+), CD8(+), and CD4(+)CD8(+) T cells exist in the peripheral circulation of hypersensitive patients, often many years after the resolution of clinical manifestations. CLINICAL IMPLICATIONS: Carbamazepine-specific CD4(+), CD8(+), and CD4(+)CD8(+) T cells displaying different effector functions and homing characteristics persist in hypersensitive patients' blood for many years after resolution of clinical symptoms.     

Chronic lymphocytic leukemia with peripheral T lymphocytes expressing CD 2+, CD 3+, CD 4-, CD 8-, CD 16+, and CD 56+ and lymph-node lymphocytes expressing CD 2+, CD 3-, CD 4-, CD 8-, CD 16+, CD 38+, and CD 56+]

A 33-year-old man was hospitalized because of thrombocytopenia and severe splenomegaly. On admission 78% of peripheral lymphoid cells were abnormally large, with pale cytoplasm. Flow cytometry of the abnormal lymphocytes showed that they expressed CD 2, CD 3, CD 11, CD 16, and CD 56, but not CD 4 nor CD 8, so they were T-cell large granular lymphocytes (T-LGL). Abnormal lymphocytes obtained from a lymph node expressed CD 2, CD 16, CD 38, and CD 56, but not CD 3, CD 4, and CD 8, so they were natural killer(NK) cells. Splenectomy was performed and the operative specimen showed diffuse infiltration of pleomorphic lymphocytes, probably chronic lymphocytic leukemia cells. After splenectomy, the platelet count returned to normal but the lymphocytosis continued. Two years after discharge, chemotherapy was done because of thrombocytopenia and hepatomegaly. The patient died of disseminated intravascular coagulation arising from sepsis. The differences and similarities between peripheral and lymph-node lymphocytes suggest that LGL and NK cells may be differentiated from the same kind of cell, somewhat differentiated from stem cells.     

CD4+CD25+ but not CD4+Foxp3+ T cells as a regulatory subset in primary biliary cirrhosis

Increasing evidence indicates a role for regulatory T cells (Tregs) in the immune response and in autoimmune diseases, but the role of Tregs and cytokines in autoimmune hepatic diseases remains largely unclear and controversial, especially in patients with primary biliary cirrhosis (PBC). This study was undertaken to investigate Tregs and different cytokines in the liver and peripheral blood of PBC patients. We found that these patients demonstrated a reduction of CD4⁺CD25⁺ T cells but elevated CD4⁺Foxp3⁺ T cells in peripheral blood mononuclear cells (PBMCs) and CD4⁺ T cells. The percentage of CD4⁺CD25⁺ T cells in PBMCs was negatively correlated with elevated plasma interferon (IFN)-γ levels. A liver-specific analysis showed that the frequency of Foxp3⁺ Tregs, transforming growth factor (TGF)-β1 and IFN-γ were increased in PBC patients. Our findings suggest that an imbalance between CD4⁺CD25⁺ Tregs and cytotoxic cytokines plays a crucial role in the pathogenesis of PBC while the role of Foxp3 needs further investigation.     

Characterization of CD4- CD8- CD3+ T-cell receptor-alphabeta+ T cells in murine cytomegalovirus infection

In this study, we have investigated that after the intraperitoneal infection with murine cytomegalovirus (MCMV), the CD3+ CD4- CD8-(double negative; DN) T-cell receptor (TCR)alphabeta+ T cells increased in peritoneal cavity, liver and spleen in both resistant C57BL/6 and susceptible BALB/c mice. The total cellular population of these cells showed peak levels around day 5 after infection in all the three investigated organs and the following phenotypical and functional characteristics emerged. The peritoneal DN TCRalphabeta+ T cells expressed highly skewed TCRVbeta8 on day 5 after infection compared with the uninfected mice, but those in spleen and liver showed moderate and low skewed TCRVbeta8, respectively. The percentages of NK1.1+ DN TCRalphabeta+ T cells gradually decreased as did modulation of some of their activation markers consistent with an activated cell phenotype. The peritoneal DN TCRalphabeta+ T cells on day 5 after infection expressed the genes of interferon-gamma (IFN-gamma), tumour necrosis factor-alpha, Eta-1 (early T-cell activation-1) and MCP-1 (monocyte chemoattractant protein 1) but lacked expression of interleukin-4 (IL-4). After in vitro stimulation with phorbol 12-myristate 13-acetate and calcium ionophore in the presence of Brefeldin A, higher frequencies of intracellular IFN-gamma+ DN TCRalphabeta+ T cells were detected in all three investigated organs of infected mice compared with those of uninfected mice. Stimulation of peritoneal DN TCRalphabeta+ T cells with plate-bound anti-TCRbeta monoclonal antibodies showed proliferation and also produced IFN-gamma but not IL-4. These results suggest that DN TCRalphabeta+ T cells were activated and may have an antiviral effect through producing IFN-gamma and some macrophage-activating factors during an early phase of MCMV infection.     

肾移植后外周血CD4+及CD8+T细胞亚群计数的临床意义

背景：临床上常以流式细胞检测受者外周血CD4、CD8细胞比值来揭示与排斥或感染相关的关系。 目的：探讨肾移植后排斥或感染时外周血CD4⁺及CD8⁺T细胞(简称CD4和CD8细胞)亚群计数的变化和意义。 方法：应用流式细胞仪检测肾移植121例受者CD4、CD8细胞数进行检测。根据入院病情将患者分为移植后正常组、急性排斥组、肺部感染组进行观察。 结果与结论：移植后正常患者和急性排斥患者相比,CD4、CD8细胞数差异均无显著性意义(P > 0.05)。肾移植后肺部感染患者CD4、CD8细胞数则均显著低于移植后正常组(P < 0.001)。当感染控制、症状改善时,CD4、CD8细胞数显著升高 (P < 0.001)。说明肾移植后CD4和CD8细胞计数可以作为免疫状态的参考,其对于感染的参考价值大于排斥,动态观察分析有助于指导治疗。     

Ontogeny of a novel CD4+CD8-CD3- thymocyte subpopulation: a comparison with CD4- CD8+ CD3- thymocytes

We have studied the ontogeny of a novel thymocyte subset, CD4+CD8-CD3-. Three-colour flow cytometric analysis demonstrated that these cells constituted approximately 1% of the total thymocyte content in adult CBA mice, and were not present in lymph nodes. They were mainly blastic, cortisone-sensitive, and localized in the outer thymic cortex. During foetal life they were first observed at day 15 and reached a maximum (6%) at day 17, beyond which they decreased to the adult level. This kinetic profile was similar to that of the CD4-CD8+CD3- subpopulation, except that the CD4+CD8-CD3- cells appeared slightly earlier and their percentage was lower. Both these populations appeared after the CD4-CD8-CD3- cells but before the CD4+CD8+CD3- cells. Similar observations were made during thymic reconstitution following dexamethasone treatment. In this case, both CD4+CD8-CD3- and CD4-CD8+CD3- thymocytes disappeared 48 h after the treatment. While their absolute number increased up to 14 days post-treatment, their percentage was maximal at day 7 post-treatment and returned to normal values by day 10 post-treatment. These results argue strongly that not only the CD4-CD8+CD3- population but also the CD4+CD8-CD3- population can be considered an intermediate precursor in CBA thymuses.     

Relationships between 2H4 (CD45RA) and UCHL1 (CD45RO) expression by normal blood CD4+CD8-, CD4-CD8+, CD4-CD8dim+, CD3+CD4-CD8- and CD3-CD4-CD8- lymphocytes.

We characterized and established relationships between the expression of membrane 2H4 (CD45RA) and UCHL1 (CD45RO) by enriched lymphocyte fractions prepared by selective immunomagnetic depletion of monoclonal antibody-defined populations. Cell fractions analysed in this study could be divided into two broad groups according to the presence (CD3+CD4+CD8-, CD3+CD4-CD8+, CD3+CD4-CD8dim+ and CD3+CD4-CD8-) or absence (CD3-CD4-CD8dim+ and CD3-CD4-CD8-) of the CD3 antigen. Preliminary studies confirmed a reciprocal relationship for CD45RA and CD45RO expression by major lymphoid components and further showed that the level or intensity of membrane 2H4 staining (2H4+, 2H4int and 2H4-) could be directly related to UCHL1 expression. As a reflection of their differential functions, the various CD3+ populations examined showed much greater heterogeneity in 2H4 and UCHL1 expression. CD3+CD4+CD8- cells generally showed significant proportions of 2H4+, 2H4int and 2H4- components, whereas the CD3+CD4-CD8+ population was characterized by a predominance of 2H4+ cells. The results of this current investigation further suggested a higher proportion of dual-positive (2H4+UCHL1+) cells and a much greater degree of inter-individual variation than previously suspected. In contrast to CD3+ lymphocytes, natural killer (NK) associated CD3-CD4-CD8dim+ and CD3-CD4-CD8- populations were mostly 2H4+ with only minor 2H4int components and very low expression of UCHL1. An additional observation of note was that the proportions of 2H4+ and 2H4- cells comprising the CD4+CD8- fraction in any given individual was highly correlated (P = 0.002) with the distributions of 2H4+ and 2H4- components within the CD4-CD8+ fraction. This suggests the possible existence of a common control mechanism for the acquisition of immunological memory by distinct lymphocyte populations and further indicates that individual variations in the distribution of 2H4/UCHL1 lymphocyte subpopulations may be a direct consequence of 'immunological experience' rather than age alone.     

CD3+,CD4+及CD8+T淋巴细胞数目改变作为早期诊断脓毒血症指标可行性的Meta分析

目的:评价脓毒血症CD3+,CD4+以及CD8+T淋巴细胞数目的改变以帮助早期诊断.方法:计算机检索Medline,PubMed,SPINGER,John Wiley,Science Direct,EBSCO,知网以及万方数据库,检索时限均为建库至2017年2月,收集关于脓毒血症CD3+,CD4+以及CD8+T淋巴细胞数目改变的病例对照研究.由2位研究者按照纳入和排除标准独立筛选文献、提取资料和评价质量后,用Revman5.3软件进行Meta分析.评价早期脓毒血症患者CD3+,CD4+以及CD8+T淋巴细胞数目与对照组的差异.结果:早期脓毒血症患者CD3+,CD4+以及CD8+T淋巴细胞数目均比对照组人群低,差异有统计学意义(P<0.05);死亡组脓毒血症患者CD3+,CD4+以及CD8+T淋巴细胞数目均比存活组病人低,差异有统计学意义(P<0.05).结论:CD3+,CD4+以及CD8+T淋巴细胞数目改变能够帮助早期脓毒血症的诊断以及预后.     

A patient with simultaneous absence of "classical" natural killer cells (CD3-, CD16+, and NKH1+) and expansion of CD3+, CD4-, CD8-, NKH1+ subset

The clinical manifestations of putative natural killer (NK) cell deficiency are not well-known but theoretically should include recurrent tumors and systemic viral infections. In this article, we discuss a patient with recurrent condylomata, vulvar and cervical carcinoma in situ, pulmonary infiltrates of unknown significance, and a hypercoagulable state. This patient has a dramatic persistent deficiency in her circulating "classic" NK cells (CD3-, CD16+, NKH1+) and a simultaneous persistent expansion of a normally minor lymphocyte cell subset (CD3+, CD4-, CD8-, NKH1+) that does not express the alpha beta heterodimer of the T cell receptor. T-lymphocyte function, as measured by mitogen and alloantigen responsiveness in vitro, was normal. The coexistence of this particular clinical complex with this unusual set of laboratory abnormalities tends to emphasize our meager understanding of the biologic role of NK cells. At the very least, these findings suggest that the clinical manifestations of NK cell deficiency need not be dominated by disseminated systemic viral infections and that perhaps there should be a higher index of suspicion for the scrutinization of NK cell function.     

Expression of CD11b (Leu15) antigen on CD3+, CD4+, CD8+, CD16+ peripheral lymphocytes. Estimation of CD3+8+11b+ and CD3+4-8-11b+ T-cell subsets using a single laser flow cytometer.

CD11b (Leu15) epitope is expressed on 20-30% of peripheral blood lymphocytes, including CD16+ large granular lymphocytes and CD8+ cells. This study confirms that 30% of CD8+ lymphocytes and virtually all CD16+ NK cells from healthy subjects express this determinant. In parallel, our data show that various proportions of CD3+4-8-, TCR-delta cytotoxic T lymphocytes and occasionally CD4+ lymphocytes subsets could also express this epitope. The CD8+11b+ phenotype is associated with suppression of T-cell proliferative response and has been extensively used to characterize suppressor T lymphocytes. Since about 25% of CD8 lymphocytes are non-T (CD3-) and express the CD16 NK antigen (CD8+16+3-), the expression of CD11b was also studied on CD8+3+ T-cell and CD8+16+ NK-cell subsets. To this end, we developed three methods using a flow cytometer equipped with a single laser and two fluorescence detectors. Results showed that T CD8+3+11b+ and NK CD8+16+11b+ lymphocytes account for 30% and 70% of CD8+11b+ cells respectively. Consequently, the CD8+3+11b+ phenotype would be more specific for suppressor T lymphocytes than the total CD8+11b+ phenotype which includes high proportions of CD16+ NK cells.     

Clinical field site evaluation of the FACSCount for absolute CD3+, CD3+ CD4+, and CD3+ CD8+ cell count determinations in Thailand.

The FACSCount flow cytometer absolute CD3+, CD3+ CD4+, and CD3+ CD8+ cell counts measured at a field site hospital laboratory in Thailand were compared to FACScan absolute counts obtained at a nearby research laboratory. Correlation coefficients for 208 samples were > or = 0.95. The FACSCount was accurate, and it was easier and less expensive to operate than the FACScan. Additionally, the FACScan-generated lymphocyte percentage value was accurate for use with the FACScan SimulSET software.     

Functionality of CD4+ and CD8+ T cells from tonsillar tissue

For many years, tonsillectomy has been used routinely in children to treat chronic or recurrent acute tonsillitis. Palatine tonsils are secondary lymphoid organs and the major barrier protecting the digestive and respiratory tracts from potential invasive microorganisms. They have been used as sources of lymphoid tissue; however, despite the hundreds of papers published on tonsillectomy, no studies addressing the functionality of the CD4(+) and CD8(+) T cells from chronically infected tonsils have yet been published. The aim of this study was to analyse the functionality of the CD4(+) and CD8(+) T cells with respect to tonsillar tissue. We used an affordable approach to measure the frequency of antigen-specific CD4(+) T cells, the direct ex-vivo cytotoxicity of CD8(+) T cells, memory T cell phenotype, cytokine profile and DC phenotype. Our results demonstrate that CD4(+) and CD8(+) T cells from tonsillar tissue are totally functional, as shown by their ability to produce cytokines, to degranulate and to differentiate into effector-memory T cells.     

Functional and Vbeta repertoire characterization of human CD8+ T-cell subsets with natural killer cell markers,CD56+ CD57- T cells,CD56+ CD57+ T cells and CD56- CD57+ T cells

We investigated the individual CD8+ populations with natural killer (NK) cell markers (NK-type T cell); CD56 single positive (CD56)-T cells, CD56/CD57 double positive (DP)-T cells and CD57 single positive (CD57)-T cells in the peripheral blood. All NK-type T-cell populations expressed CD122 and intermediate levels of T-cell receptor (TCR; regular CD8+ T cells are CD122- and express high levels of TCR). The number of both DP-T cells and CD57-T cells, but not CD56-T cells, gradually increased with age. All NK-type T-cell populations produced larger amounts of interferon-gamma than did regular CD8+ T cells after stimulation with interleukin (IL)-2, IL-12 and IL-15. However, CD56-T cells and CD57-T cells but not DP-T cells showed a potent antitumour cytotoxity to NK-sensitive K562 cells, whereas only CD56-T cells showed a potent cytotoxity to NK-resistant Raji cells. Furthermore, although NK-type T cells produced large amounts of soluble Fas-ligands, their cytotoxic activities appeared to be mediated by the perforin/granzyme pathway. The oligoclonal or pauciclonal expansions of certain VbetaT cells were found in each NK-type T-cell population. The non-variant CDR3 region(s) for the TCRbeta chain(s) showed CD57-T cells and CD56-T cells to be derived from distinct origins, while the DP-T cell population consisted of a mixture of the clones seen in both CD56-T cells and CD57-T cells. Our results suggest that CD57-T cells and CD56-T cells are functionally and ontogenically different populations while DP-T cells appear to originate from both CD56-T cells and CD57-T cells.