scholarly journals Regulatory functions of hapten-reactive helper and suppressor T lymphocytes. III. Amplification of a generation of tumor-specific killer T-lymphocyte activities by suppressor T-cell-depleted hapten-reactive T lymphocytes.

1979 ◽  
Vol 149 (1) ◽  
pp. 185-199 ◽  
Author(s):  
T Hamaoka ◽  
H Fujiwara ◽  
K Teshima ◽  
H Aoki ◽  
H Yamamoto ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Lymphocyte ◽  
Lethal Dose ◽  
Cell Activity ◽  
Helper T Cell ◽  
Relative Susceptibility ◽  
Helper T Lymphocytes ◽  
Lymphocyte Activity

2,4.6-trinitrophenyl (TNP)-reactive T-cell activities were raised in mice by immunization with TNP-isologous mouse gamma globulin. After establishing that TNP-reactive T lymphocytes can serve as amplifier cells for induction of killer T lymphocytes in allogeneic system, we explored the possibility of this hapten-reactive T-cell system to amplify tumor-specific killer T-lymphocyte activity in the syngeneic system. We utlized relatively weak immunogenic syngeneic plasmacytoma X5563 in C3H/He mice. Analysis of the TNP-reactive T-cell activities revealed that such T lymphocytes express the biological functions of both major subtypes of regulatory T cells, namely suppressors and helpers, and that TNP-reactive suppressor and helper T lymphocytes, respectively, differ in their relative susceptibility to specific inactivation by TNP conjugates of the nonimmunogenic D-amino acid copolymer, D-glutamic acid, and D-lysine (D-GL). By taking advantage of the relative susceptibility-difference to TNP-D-GL, selective inactivation of TNP-reactive suppressor T cells was induced by appropriate treatment with TNP-D-GL, and the generation of TNP-reactive helper T-cell activity was amplified. The supplement of augmented TNP-reactive helper T-cell activity to the system at the immunization with syngeneic X5563 with TNP-haptenation, resulted in a striking augmentation of induction of tumor-specific killer T-lymphocyte activity, and a considerable number of hosts survived after the challenge with lethal dose of viable tumor cells. Thus, appropriate manipulations designed to induce potent hapten-reactive helper T-lymphocytes provided the potential for a very effective mode of immunoprophylaxis against tumor.

scholarly journals Regulatory functions of hapten-reactive helper and suppressor T lymphocytes. II. Selective inactivation of hapten-reactive suppressor T cells by hapten-nonimmunogenic copolymers of D-amino acids, and its application to the study of suppressor T-cell effect on helper T-cell development

1977 ◽  
Vol 146 (1) ◽  
pp. 91-106 ◽  
Author(s):  
T Hamaoka ◽  
M Yoshizawa ◽  
H Yamamoto ◽  
M Kuroki ◽  
M Kitagawa
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Development ◽  
Cell Activity ◽  
Helper T Cells ◽  
Suppressor T Cells ◽  
Helper T Cell ◽  
Suppressor T Cell ◽  
Suppressor T Lymphocytes

An experimental condition was established in vivo for selectively eliminating hapten-reactive suppressor T-cell activity generated in mice primed with a para-azobenzoate (PAB)-mouse gamma globulin (MGG)-conjugate and treated with PAB-nonimmunogenic copolymer of D-amino acids (D- glutamic acid and D-lysine; D-GL). The elimination of suppressor T-cell activity with PAB-D-GL treatment from the mixed populations of hapten- reactive suppressor and helper T cells substantially increased apparent helper T-cell activity. Moreover, the inhibition of PAB-reactive suppressor T-cell generation by the pretreatment with PAB-D-GL before the PAB-MGG-priming increased the development of PAB-reactive helper T-cell activity. The analysis of hapten-specificity of helper T cells revealed that the reactivity of helper cells developed in the absence of suppressor T cells was more specific for primed PAB-determinants and their cross-reactivities to structurally related determinants such as meta-azobenzoate (MAB) significantly decreased, as compared with the helper T-cell population developed in the presence of suppressor T lymphocytes. In addition, those helper T cells generated in the absence of suppressor T cells were highly susceptible to tolerogenesis by PAB-D- GL. Similarly, the elimination of suppressor T lymphocytes also enhanced helper T-cell activity in a polyclonal fashion in the T-T cell interactions between benzylpenicilloyl (BPO)-reactive T cells and PAB- reactive T cells after immunization of mice with BPO-MGG-PAB. Thus inhibition of BPO-reactive suppressor T-cell development by the BPO-v-GL- pretreatment resulted in augmented generation of PAB-reactive helper T cells with higher susceptibility of tolerogenesis to PAB-D-GL. Thus, these results support the notion that suppressor T cells eventually suppress helper T-cell activity and indicate that the function of suppressor T cells related to helper T-cell development is to inhibit the increase in the specificity and apparent affinity of helper T cells in the primary immune response. The hapten-reactive suppressor and helper T lymphocytes are considered as a model system of T cells that regulate the immune response, and the potential applicability of this system to manipulating various T cell-mediated immune responses is discussed in this context.

scholarly journals The mechanism of tolerance induction in thymus-derived lymphocytes; I. intracellular inactivation of hapten-reactive helper T lymphocytes by hapten-nonimmunogenic copolymer of D-amino acids.

1975 ◽  
Vol 141 (6) ◽  
pp. 1308-1328 ◽  
Author(s):  
T Hamaoka ◽  
U Yamaskita ◽  
T Takami ◽  
M Kitagawa
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
Cell Activity ◽  
Tolerance Induction ◽  
Adoptive Cell Transfer ◽  
Helper T Cell ◽  
Cell Reactivity ◽  
Helper T Lymphocytes ◽  
Specific Tolerance

Treatment of a p-azobenzoate (PAB) derivative of a copolymer of D-glutamic acid and D-lysine (D-GL) induced a profound state of unresponsiveness to PAB-reactive helper T lymphocytes generated in PAB-mouse gamma globulin (MGG)-primed mice. This unresponsiveness in T lymphocytes was specific for PAB-reactive cells, since the bacterial alpha-amylase-, keyhole limpet hemocyanin-, or ovalbumin-primed helper T lymphocytes were not suppressed by PAB-D-GL treatment. Taking advantage of the relative ease with which PAB-D-GL can induce specific unresponsiveness to helper T lymphocytes in an animal previously primed with PAB-MGG, it was possible to approach certain questions concerning the mechanisms of tolerance-induction and the fate of tolerant helper T lymphocytes in the PAB-D-GL model by utilizing a classical adoptive cell transfer systemmelimination of the possibility of carry-over of the tolerogen with cells or of the generation of suppressor cells as the result of PAB-D-GL treatment as an explanation of the suppression of helper T-cell activity strongly inplicates the existence of a central intracellular mechanism of specific tolerance on the helper T-cell level. The possibility that suppression of the activity of PAB-reactive helper T lymphocytes by PAB-D-GL reflects simple blocking of surface receptor molecules on T lymphocytes was ruled out as it was found that the helper activity of PAB-reactive cells was minimally suppressed even when PAB-D-GL was directly exposed in vitro to helper T lymphocytesmmoreover, the most conclusive evidence on te the tolerant state induced by in vivo exposure of primed T cells to PAB-D-GL. It appears, therefore, that specific tolerance induced by PAB-D-GL' TO PAB-reactive helper T lymphocytes is an example of irreversible inhibition of T-cell reactivity to antigen, reflecting yet to be determined events at the intra- and subcellular levels.

scholarly journals Expansion of a unique subpopulation of cytotoxic T cells that express a C alpha V delta 1 T-cell receptor gene in a patient with severe persistent neutropenia

Blood ◽  
1992 ◽  
Vol 80 (12) ◽  
pp. 3157-3163
Author(s):  
I Bank ◽  
M Book ◽  
L Cohen ◽  
A Kneller ◽  
E Rosental ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Receptor ◽  
T Lymphocyte ◽  
Peripheral Blood ◽  
Gene Segment ◽  
Cell Receptor ◽  
Severe Neutropenia ◽  
Pcr Analysis

CD8+ T-lymphocyte populations may be expanded in the peripheral blood of patients with chronic idiopathic neutropenia and may be involved in suppression of granulopoiesis. In this report, we have analyzed the T-cell receptor (TCR) used by the T lymphocytes of a patient with chronic severe neutropenia. Using specific oligonucleotides in the polymerase chain reaction (PCR) to amplify cDNA specific for the different families of the V alpha, V beta, and V delta TCR genes, and monoclonal antibodies (MoAbs) to examine T-lymphocyte subsets and their TCR, a persistent expansion of CD3+CD8+ T lymphocytes and a reduced repertoire of TCR V alpha and V beta genes were found in the patient's peripheral blood mononuclear cell (PBMC) preparations. A predominant portion of the T lymphocytes expressed a unique TCR structure. Thus, we found that, despite the fact that 98% of the T cells expressed alpha beta TCR on the surface membrane and less than 2% expressed tau delta TCR, nonetheless, 40% to 60% of the T cells stained positively with anti V delta 1 MoAb. Using the PCR analysis, the V delta 1 gene segment was found to be rearranged to C alpha, rather than to C delta genes. The expanded C alpha V delta 1+ cells, which are found only rarely in normal PB, expressed CD8 and were cytotoxic, and the C alpha V delta 1 receptor was functional in cytotoxicity. This constitutes the first description of an expansion of cytotoxic CD8+ lymphocytes expressing a functional “hybrid” C alpha V delta 1 gene in vivo, and suggests a pathogenic role for CD8+ C alpha V delta 1+ cells in some patients with idiopathic neutropenia.

scholarly journals Follicular B helper T cell activity is confined to CXCR5hiICOShi CD4 T cells and is independent of CD57 expression

2006 ◽  
Vol 36 (7) ◽  
pp. 1892-1903 ◽  
Author(s):  
Ata-Ur Rasheed ◽  
Hans-Peter Rahn ◽  
Federica Sallusto ◽  
Martin Lipp ◽  
Gerd Müller
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Cell Activity ◽  
Helper T Cell

scholarly journals Increase in inflammatory T cell subsets in atrial fibrillation: the missing link underlying inflammation in AF

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
I.E Dumitriu ◽  
P Dimou ◽  
S Kaur ◽  
S Dinkla ◽  
J.C Kaski ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Inflammatory Cytokines ◽  
T Lymphocyte ◽  
Treg Cells ◽  
Funding Source ◽  
Functional Assays

Abstract Background The precise role of inflammation in the development and perpetuation of atrial fibrillation (AF) is yet to be fully uncovered. T lymphocytes have pivotal roles in orchestrating inflammation. Specialised subsets of lymphocytes either promote or prevent inflammation. We are investigating a unique subset of lymphocytes, the CD4+CD28null T cells that expand in patients with chronic inflammation. These cells secrete high levels of pro-inflammatory cytokines and have cytolytic function. CD4+CD28null T cells are normally maintained under control by regulatory T cells (Treg), a specialised subset of T lymphocytes with suppressive function that maintain immune homeostasis and prevent pathogenic immune responses. The role of CD4+CD28null and Treg cells has not been investigated in AF. Purpose We hypothesised that in AF the balance between pro-inflammatory and regulatory T lymphocytes is skewed in favour of inflammatory T cells, which may sustain inflammation in AF. Methods Circulating CD4+CD28null T lymphocytes and Tregs were quantified by flow cytometry in paroxysmal and persistent AF patients and healthy controls (n=30). Inflammatory cytokines were quantified in serum and the function of T lymphocyte subsets was investigated using ex vivo functional assays. Results CD4+CD28null T lymphocytes were significantly increased in the circulation of AF patients compared to controls. Of note, a higher proportion of patients with persistent AF showed an increase in inflammatory CD4+CD28null T lymphocytes compared to patients with paroxysmal AF. A marked reduction in Treg cells was present in AF patients compared to controls. Functional assays showed that IL-7 and IL-15 cytokines were responsible for CD4+CD28null T lymphocyte expansion in AF patients. Conclusions We show that patients with AF have marked changes in T lymphocytes subsets: pro-inflammatory CD4+CD28null T cells increase significantly, whilst anti-inflammatory Tregs are significantly reduced. We show for the first time that the cytokines IL-7 and IL-15 are the main drivers of CD4+CD28null T cell expansion in AF patients. These novel findings may reveal novel therapeutic strategies (e.g. cytokine blockade) to re-establish the balance between pro- and anti-inflammatory mechanisms at work in AF to improve patient outcomes. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Cytotoxicity Is Not Required for the Anti-Leukemia Efficacy of Human H-Y-Specific CD4+ T Lymphocytes In Vivo.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3553-3553
Author(s):  
Attilio Bondanza ◽  
Lothar Hambach ◽  
Zohara Aghai ◽  
Monica Casucci ◽  
Bart Nijmeijer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Cell Clone ◽  
Scid Mice ◽  
Helper T Cell ◽  
T Cell Clone ◽  
Control Clone

Abstract Abstract 3553 Poster Board III-490 Introduction Minor histocompatibility antigens (mHag) play a major role in the graft-versus-leukemia (GvL) effect following HLA-matched allogeneic hemopoietic cell transplantation (allo-HCT). Clinically, the GvL effect coincides with the emergence of mHag-specific CD8+ cytotoxic T lymphocytes (CTL). Experimentally, targeting a single mHag with human CD8+ CTL has a major anti-leukemia effect in NOD/scid mice. Altogether, these observations suggest that mHag-specific cytotoxicity by CD8+ T cells is an important component of the GvL effect. In contrast, little is known on the contribution of mHag-specific CD4+ T cells. Female-to-male allo-HCT is characterized by a low rate of leukemia relapse, indicating that H-Y-encoded mHag are potent leukemia-regression antigens. Earlier, we described a DRB3*0301-restricted H-Y mHag epitope inducing CD4+ helper T-cell responses in H-Y-mismatched HLA-matched allo-HCT. Aim: The aim of this study is to elucidate the role of mHag-specific human CD4+ T lymphocytes on the GvL effect. Methods The ALL-CM leukemia cell line, derived from a male (i.e. H-Y+) HLA-A0201+, DRB30301+ patient, reproducibly engrafts in NOD/scid mice after administration of 10×106 cells. Both an HLA-A0201-restricted H-Y-specific CD8+ CTL clone and the DRB30301-restricted H-Y-specific CD4+ helper T-cell clone that we earlier described were used to investigate the anti-leukemia efficacy of CD8+ and CD4+ T cells in NOD/scid mice. Results In vitro, the CD8+ H-Y specific CTL clone was highly cytotoxic against the ALL-CM leukemia. The H-Y specific CD4+ helper T-cell clone did not lyse the leukemia, but produced IFN-γ upon recognition. Infusion of the H-Y-specific CD8+ CTL clone (25×106 cells/mouse) 3 days after ALL-CM leukemia challenge significantly delayed leukemia progression by 3 weeks compared to a CMV-specific CD8+ CTL control clone (p<0,001). Despite no measurable in vitro cytotoxicity, the H-Y-specific CD4+ helper T-cell clone (25×106 cells/mouse) delayed leukemia progression by 2 weeks compared to a leukemia non-reactive HLA-DR1-specific CD4+ helper T-cell control clone (p<0,001). In vitro co-incubation of the H-Y-specific CD4+ helper T-cell clone did not influence leukemia proliferation but induced up-regulation of MHC-class I and II, CD80, CD86 and CD40. In vitro, pre-incubation of leukemia cells with the H-Y-specific CD4+ helper T-cell clone irradiated did not improve the in vivo anti-leukemia efficacy of the H-Y-specific CD8+ CTL clone. Co-infusion of the H-Y specific CD4+ helper T-cell clone did not augment the in vivo persistence of the H-Y-specific CD8+ CTL T-cell clone. Nevertheless, the co-infusion resulted in a delay in leukemia progression of approximately 5 weeks, suggesting an additive, non overlapping anti-leukemia mechanism. Conclusions Minor Hag-specific human CD4+ T lymphocytes may contribute to the GvL effect through a direct, non cytotoxic mechanism, which could be additive to that of CD8+ CTL. The nature of this non cytotoxic GvL effect is currently under investigation. A.B. and L.H. equally contributed to this study. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Virus-replicating T cells in the immune response of mice. II. Characterization of T cells capable of replicating vesicular stomatitis virus.

1978 ◽  
Vol 148 (4) ◽  
pp. 837-849 ◽  
Author(s):  
N Minato ◽  
Y Katsura
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Population ◽  
Vesicular Stomatitis Virus ◽  
Major Part ◽  
Cell Activity ◽  
Helper T Cells ◽  
Suppressor T Cells ◽  
Helper T Cell ◽  
Vesicular Stomatitis

Immunocytological properties of the splenic T cell (Tv) which develop into virus plaque-forming cells in response to the antigenic challenge in vitro were investigated in relation to the properties of helper T cells and suppressor T cells in antibody response. Tv was observed in spleen around 1 wk after the intravenous injection of mice with 10(7) sheep erythrocytes. This contrasted with the finding that both helper T cells and suppressor T cells developed as early as 3 days after the immunization. Tv was proliferative in response to the antigenic stimulation, whereas helper T-cell activity could be expressed without cell division. Development of Tv to virus plaque-forming cells was much more dependent on macrophages than the generation of helper activity. Tv was found in nylon wool adherent fraction, whereas helper T cell was found in both nylon adherent and nonadherent fractions. Tv belongs to the short-lived and nonrecirculating T-cell population (T1), whereas the major part of helper T cells belongs to the long-lived and recirculating T-cell population (T2). These results strongly suggest that vesicular stomatitis virus infect and replicate in the different subset(s) of T cell(s) to which the major part of helper T cells belong.

scholarly journals Causes of T lymphocyte activation in HIV-infected patients coinfected with hepatitis C virus

2016 ◽  
Vol 88 (11) ◽  
pp. 22-28
Author(s):  
K V Shmagel ◽  
N G Shmagel ◽  
L B Korolevskaya ◽  
E V Saydakova ◽  
V A Chereshnev
Keyword(s):  
T Cells ◽  
Hepatitis C ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cell Activation ◽  
Lymphocyte Activation ◽  
Cd8 T Cell ◽  
Cd8 T Lymphocytes

Aim. To establish the causes of T lymphocyte activation in human immunodeficiency virus (HIV)-infected patients coinfected with hepatitis C (HCV) who are adherent to their antiretroviral therapy regimen and interferon untreated. Subjects and methods. Examinations were made in 62 people who were HIV+HCV-positive (n=21), HIV+HCV-negative (n=21), and noninfected volunteers (n=20). The activation (CD38+HLA-DR+) and proliferation (Ki-67+) of CD4+ and CD8+ T lymphocytes were estimated. The blood concentration of intestinal fatty acid-binding protein (I-FABP) was determined. Results. The proportion of activated cells among the CD4+ T lymphocytes was equal in the HIV+HCV-positive and HIV+HCV-negative groups. But these indicators were statistically significantly higher than those in the controls (HIV- HCV-). CD8+ T cell activation was greater in the HIV/HCV-coinfected patients than that in the other groups and that was higher in the HIV monoinfected than in the noninfected. The blood I-FABP concentrations were elevated in the HIV+HCV-positive and HIV+HCV groups compared with those in the HIV-HCV-negative group, but these did not differ among themselves. In the HIV+HCV-negative patients, CD4+ and CD8+ T cell activation directly and statistically significantly correlated with blood I-FABP levels. In the HIV+HCV-positive group, this correlation remained only for CD4+ T lymphocytes. CD8+ T cell activation in HIV/HCV-coinfected patients was unrelated to I-FABP concentrations. Conclusion. The increased activation of CD4+ and CD8+ T lymphocytes in HIV monoinfection was found to be associated with intestinal epithelial destruction and unrelated to cell division processes. In HIV/HCV coinfection, the activated state of CD4+ T cells is determined by both the level of proliferative processes and impairment of the intestinal barrier and that of CD8+ T cells is only by proliferation.

In Vitro Generation of Mature T Lymphocytes From Human Ips Cells and Genetic Analysis of TCR Gene Rearrangements

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2984-2984
Author(s):  
Toshinobu Nishimura ◽  
Shin Kaneko ◽  
Yoko Tajima ◽  
Naoya Takayama ◽  
Ai Tachikawa-Kawana ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Lymphocyte ◽  
Ips Cells ◽  
Therapeutic Effects ◽  
Gene Rearrangements ◽  
Autologous Tumor ◽  
Antigen Specificity

Abstract Abstract 2984 T lymphocytes play central roles in cellular immunity, exerting their proliferative and effector activities when they recognize antigens via T-cell receptors (TCRs) in HLA-restricted and antigen-specific manner. Adoptive cell transfer therapy (ACT), the administration of ex vivo-activated and -expanded autologous tumor-reactive T lymphocytes, is currently one of the effective methods for immunotherapy, especially for treatment of metastatic solid tumors including melanoma. However, the successful applications of this method are currently limited for tumor therapies. To broaden the range of the application of ACT, we endeavored to develop easier method to obtain cells that carry antigen-specific TCR genes. For the purpose, generation of induced pluripotent stem (iPS) cells from an antigen-reactive single T lymphocyte is attractive and rewarding way. iPS cells have a capacity for unlimited self-renewal while maintaining pluripotency. These features may enable us to induce an unlimited number of T lymphocytes, especially high proliferative naïve / central memory-type T lymphocytes, showing reactivity to specific antigens. If they retain properties of naïve T lymphocytes, they may proliferate for a longer period and achieve better therapeutic effects than their peripheral blood counterparts expanded in vitro. Peripheral T lymphocytes were isolated from healthy volunteers. Then reprogramming factors (OCT4, SOX2, KLF4, and c-MYC) were transduced into fresh or frozen / thawed T lymphocytes. T lymphocyte-derived iPS-like colonies were observed within 3 weeks and they were isolated and clonally expanded. They exhibited standard ES-like morphology, cell surface marker expression, alkaline phosphatase activity, as well as differentiation potential into various tissues related to all three germ layers. Human TCRs are encoded in four genes (TCRA, TCRB, TCRG, TCRD), which should be genetically assembled in an irreversible manner during T-lymphocyte development. This feature allowed us to retrospectively confirm that the iPS cells were generated from T lymphocyte. The TCR gene rearrangements encoded in an iPS colony were clonal for all iPS lines, indicating that each iPS colony was derived from a single T lymphocyte. Sequence analyses of TCR genes revealed whether the rearrangements were productive, and the productivity might promise the conservation of TCR genes rearrangement during the reprogramming process. Next, we tried to re-differentiate T lymphocyte derived-iPS (T-iPS) cells into T cells by co-culturing them with murine stromal cell layers (OP9 and OP9-DL1). T-cell differentiation was evidenced by the expression of T-cell markers, such as CD5, CD7, CD27, CD4, CD8, TCR α β and CD3. We obtained 33.5 ± 17.9% CD4+ CD8+ double positive (DP) cells, 6.51 ± 5.40% CD4+ CD8− single positive (SP) cells and 3.80 ± 1.28% CD4− CD8+ SP cells. They could be activated via TCR stimulation, and produce cytokines as functionally matured T lymphocytes do. The re-differentiation efficiency of T-iPS cells was higher than those of other pluripotent stem cells, such as embryonic stem (ES) cells, fibroblasts derived-iPS cells, or cord blood derived-iPS cells. Transcribed TCR mRNA sequences in re-differentiated T cells were analyzed, and they were revealed to be identical to that engraved in the pre-differentiated T-iPS cells genome in CD4+ CD8+ DP phase. However, fully matured CD4+ CD8− or CD4− CD8+ SP phase cells had several TCRA gene rearrangement patterns distinct from the original T-iPS cell's. On the other hand, TCRB gene maintained identity with the original. The variance of the sequences, especially antigen-recognition site sequences, indicated that the antigen-specificity in the original T lymphocyte might be converted during DP to SP transition process in vitro. These data indicate that functionally matured T cells were generated by re-differentiating T-iPS cells in vitro, and that re-assemble of TCRA genes could take place during SP T cell maturation process. In order to fulfill the T-iPS-mediated immunotherapy, we need to overcome the obstacle of further TCRA gene rearrangements. We think the solution lies in refinement of the re-differentiation method for controlling the expression of RAG1 and RAG2 recombinases or for inhibiting their activities. Disclosures: No relevant conflicts of interest to declare.

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