scholarly journals On the thymus in the differentiation of "H-2 self-recognition" by T cells: evidence for dual recognition?

1978 ◽  
Vol 147 (3) ◽  
pp. 882-896 ◽  
Author(s):  
R M Zinkernagel ◽  
G N Callahan ◽  
A Althage ◽  
S Cooper ◽  
P A Klein ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cytotoxic T Cells ◽  
Thymic Epithelial Cells ◽  
Self Recognition ◽  
Specific Cytotoxicity ◽  
Restricted Activity ◽  
Bone Marrow Chimeras ◽  
Killer T Cells

In the thymus, precursor T cells differentiate recognition structures for self that are specific for the H-2K, D, and I markers expressed by the thymic epithelium. Thus recognition of self-H-2 differentiates independently of the T cells H-2 type and independently of recognition of nonself antigen X. This is readily compatible with dual recognition by T cells but does not formally exclude a single recognition model. These conclusions derive from experiments with bone marrow and thymic chimeras. Irradiated mice reconstituted with bone marrow to form chimeras of (A X B)F1 leads to A type generate virus-specific cytotoxic T cells for infected targets A only. Therefore, the H-2 type of the host determines the H-2-restricted activity of killer T cells alone. In contrast, chimeras made by reconstituting irradiated A mice with adult spleen cells of (A X B)F1 origin generate virus-specific cytotoxic activity for infected A and B targets, suggesting that mature T cells do not change their self-specificity readily. (A X B)F1 leads to (A X C)F1 and (KAIA/DC) leads to (KAIA/DB) irradiation bone marrow chimeras responded against infected A but not B or C targets. This suggests that cytotoxicity is not generated against DC because it is abscent from the host's thymus epithelium and not against DB because it is not expressed by the reconstituting lymphoreticular system. (KBIB/DA) leads to (KCIC/DA) K, I incompatible, or completely H-2 incompatible A leads to B chimeras fail to generate any measurable virus specific cytotoxicity, indicating the necessity for I-specific helper T cells for the generation of killer T cells. Finally adult thymectomized, irradiated and bone marrow reconstituted (A X B)F1 mice, transplanted with an irradiated thymus of A origin, generate virus-specific cytotoxic T cells specific for infected A targets but not for B targets; this result formally demonstrates the crucial role of thymic epithelial cells in the differentiation of anti-self-H-2 specificities of T cells.

Rag1 Deficiency Does Not Affect Myelodysplasia but Leads to More Rapid Leukemic Transformation in a Mouse Model of MDS.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2784-2784
Author(s):  
Sheryl M Gough ◽  
Yang Jo Chung ◽  
Peter D. Aplan
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Peripheral Blood ◽  
Cytotoxic T Cells ◽  
Immune Surveillance ◽  
Severe Anemia ◽  
Control Groups ◽  
Leukemic Transformation ◽  
Significant Difference

Abstract Abstract 2784 Poster Board II-760 MDS comprises a premalignant heterogeneous group of clonal stem cell disorders that also show bone marrow dysplasia and which often evolve to acute myeloid leukemia (AML). Aplastic anemia (AA) patients also share the bone marrow failure, anemia and resulting peripheral blood cytopenias of MDS. AA is thought to be caused by an oligoclonal expansion of cytotoxic T-cells that target haematopoietic stem and progenitor cells. The severe anemia and leucopenia characteristic of both diseases is relieved in AA patients and some MDS patients by immunosuppressive therapy, supporting the role of cytotoxic T-cells in the etiology of AA. However, the role of the lymphocytes in progressive MDS remains unclear. MDS has been associated with a number of genetic aberrations, including chromosomal translocations involving the NUP98 gene. Using mice that express a NUP98-HOXD13 (NHD13) transgene, previously shown to manifest the same clinical symptoms as those of MDS patients, we have followed a cohort of NHD13/Rag1−/− mice to determine if the absence of lymphocytes, especially T cells, might 1) diminish the severity of the MDS, or 2) effect transformation and/or survival in the NHD13 mice, as would be predicted by an “immune surveillance” hypothesis of malignant transformation. Serial CBCs at two month time intervals were used to evaluate the extent of anemia and leucopenia in NHD13+ /Rag1+/+ and NHD13/Rag1−/−, as well as WT/Rag1+/− and WT/Rag1−/− control groups over a 15 month period. NHD13/Rag1−/− mice were generated by crossing the NHD13+ (C57BL/6) with the B6;129S7-Rag1tm1Mom/J mouse, and housed in a Specific Pathogen-Free (SPF) environment. Mice were euthanized and analyzed when CBCs indicated severe anemia/leucopenia or leukemic transformation, or when determined to be unwell (hunched, immobile, dyspnea) by observation. Flow cytometry, histology and genomic analyses further determined leukemia subtype, extent of infiltration and leukemia clonality. NHD13+ /Rag1+/+ and NHD13/Rag1−/− mice showed no significant differences at any two month time-point in hemoglobin (Hg), mean corpuscular volume (MCV), or platelet levels, and progressive MDS occurred in both groups. Consistent with previous studies, and excluding cases that showed evident transformation to acute leukemia, NHD13+ /Rag1+/+ mice showed low WBC, neutrophil and lymphocyte numbers, which were not significantly different from the NHD13/Rag1−/− mice. NHD13/Rag1−/− mice did however show a significantly reduced survival when compared with the NHD13+ /Rag1+/+ mice (Log-rank test, p = 0.0135), and survival medians of 11 and 13 months, respectively. Incidence of leukemic transformation was increased in the NHD13/Rag1−/− compared with the NHD13+ /Rag1+/+ mice (p=0.0079). A range of leukemia subtypes was observed in both the NHD13+ /Rag1+/+ and NHD13/Rag1−/− mice, including myeloid, B-cell, T-cell, and erythroid leukemias. In the SPF environment provided, the WT/Rag1+/− and WT/Rag1−/− control groups showed no significant difference in survival rates. Serial CBC data indicated that there was no significant difference in the timing or degree of peripheral blood cytopenias between the NHD13+ /Rag1+/+ and NHD13/Rag1−/− mice, supporting the conclusion that absence of lymphocytes does not lead to improvement in the peripheral blood cytopenias caused by the NHD13 transgene. This observation suggests that the NHD13 transgene does not produce MDS caused by an autoimmune phenomenon. The poorer survival and increased frequency of leukemic transformation in the NHD13/Rag1−/− mice suggests that lymphocytes might play a role in the evolution of MDS to AML in the NHD13 mouse model, and supports the ‘immune surveillance' hypothesis. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Selection of restriction specificities of virus-specific cytotoxic T cells in the thymus: no evidence for a crucial role of antigen-presenting cells.

1982 ◽  
Vol 156 (6) ◽  
pp. 1842-1847 ◽  
Author(s):  
R M Zinkernagel
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Cytotoxic T Cells ◽  
Antigen Presenting Cells ◽  
Cytotoxic T Cell ◽  
Antigen Presenting ◽  
Thymus Cells ◽  
Bone Marrow Chimeras

The proposal was tested that (P1 X P2) F1 leads to P1 irradiation bone marrow chimeras expressed predominantly P1-restricted T cells because donor derived stem cells were exposed to recipient derived antigen-presenting cells in the thymus. Because P1 recipient-derived antigen-presenting cells are replaced only slowly after 6-8 wk by (P1 X P2) donor-derived antigen-presenting cells in the thymus and because replenished pools of mature T cells may by then prevent substantial numbers of P2-restricted T cells to be generated, a large portion of thymus cells and mature T cells were eliminated using the following treatments of 12-20-wk-old (P1 X P2) F1 leads to P1 irradiation bone marrow chimeras: (a) cortisone plus antilymphocyte serum, (b) Cytoxan, (c) three doses of sublethal irradiation (300 rad) 2d apart, and (d) lethal irradiation (850 rad) and reconstitution with T cell-depleted (P1 X P2) F1 stem cells. 12-20 wk after this second treatment, (P1 X P2) leads to P1 chimeras were infected with vaccinia-virus. Virus-specific cytotoxic T cell reactivity was expressed by chimeric T cells of (P1 X P[2) F1 origin and was restricted predominantly to P1. Virus-specific cytotoxic T cells, therefore, do not seem to be selected to measurable extent by the immigrating donor-derived antigen-presenting cells in the thymus; their selection depends apparently from the recipient-derived radioresistant thymus cells.

scholarly journals Human fetal liver MSCs are more effective than adult bone marrow MSCs for their immunosuppressive, immunomodulatory, and Foxp3+ T reg induction capacity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi Yu ◽  
Alejandra Vargas Valderrama ◽  
Zhongchao Han ◽  
Georges Uzan ◽  
Sina Naserian ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Immune Responses ◽  
Molecular Mechanisms ◽  
Fetal Liver ◽  
Cytotoxic T Cells ◽  
Cell Contact ◽  
Adult Bone Marrow ◽  
Adult Bone

Abstract Background Mesenchymal stem cells (MSCs) exhibit active abilities to suppress or modulate deleterious immune responses by various molecular mechanisms. These cells are the subject of major translational efforts as cellular therapies for immune-related diseases and transplantations. Plenty of preclinical studies and clinical trials employing MSCs have shown promising safety and efficacy outcomes and also shed light on the modifications in the frequency and function of regulatory T cells (T regs). Nevertheless, the mechanisms underlying these observations are not well known. Direct cell contact, soluble factor production, and turning antigen-presenting cells into tolerogenic phenotypes, have been proposed to be among possible mechanisms by which MSCs produce an immunomodulatory environment for T reg expansion and activity. We and others demonstrated that adult bone marrow (BM)-MSCs suppress adaptive immune responses directly by inhibiting the proliferation of CD4+ helper and CD8+ cytotoxic T cells but also indirectly through the induction of T regs. In parallel, we demonstrated that fetal liver (FL)-MSCs demonstrates much longer-lasting immunomodulatory properties compared to BM-MSCs, by inhibiting directly the proliferation and activation of CD4+ and CD8+ T cells. Therefore, we investigated if FL-MSCs exert their strong immunosuppressive effect also indirectly through induction of T regs. Methods MSCs were obtained from FL and adult BM and characterized according to their surface antigen expression, their multilineage differentiation, and their proliferation potential. Using different in vitro combinations, we performed co-cultures of FL- or BM-MSCs and murine CD3+CD25−T cells to investigate immunosuppressive effects of MSCs on T cells and to quantify their capacity to induce functional T regs. Results We demonstrated that although both types of MSC display similar cell surface phenotypic profile and differentiation capacity, FL-MSCs have significantly higher proliferative capacity and ability to suppress both CD4+ and CD8+ murine T cell proliferation and to modulate them towards less active phenotypes than adult BM-MSCs. Moreover, their substantial suppressive effect was associated with an outstanding increase of functional CD4+CD25+Foxp3+ T regs compared to BM-MSCs. Conclusions These results highlight the immunosuppressive activity of FL-MSCs on T cells and show for the first time that one of the main immunoregulatory mechanisms of FL-MSCs passes through active and functional T reg induction.

WT1-specific CD8 + cytotoxic T cells with the capacity for antigen-specific expansion accumulate in the bone marrow in MDS

2021 ◽  
Author(s):  
Tatsuya Suwabe ◽  
Yasuhiko Shibasaki ◽  
Hiroyuki Sato ◽  
Suguru Tamura ◽  
Takayuki Katagiri ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cytotoxic T Cells ◽  
Specific Expansion

scholarly journals The critical role of T cells in glucocorticoid-induced osteoporosis

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Lin Song ◽  
Lijuan Cao ◽  
Rui Liu ◽  
Hui Ma ◽  
Yanan Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Steady State ◽  
Side Effects ◽  
Critical Role ◽  
Wild Type ◽  
Receptor Activator ◽  
Steady State Levels ◽  
Induced Apoptosis

AbstractGlucocorticoids (GC) are widely used clinically, despite the presence of significant side effects, including glucocorticoid-induced osteoporosis (GIOP). While GC are believed to act directly on osteoblasts and osteoclasts to promote osteoporosis, the detailed underlying molecular mechanism of GC-induced osteoporosis is still not fully elucidated. Here, we show that lymphocytes play a pivotal role in regulating GC-induced osteoporosis. We show that GIOP could not be induced in SCID mice that lack T cells, but it could be re-established by adoptive transfer of splenic T cells from wild-type mice. As expected, T cells in the periphery are greatly reduced by GC; instead, they accumulate in the bone marrow where they are protected from GC-induced apoptosis. These bone marrow T cells in GC-treated mice express high steady-state levels of NF-κB receptor activator ligand (RANKL), which promotes the formation and maturation of osteoclasts and induces osteoporosis. Taken together, these findings reveal a critical role for T cells in GIOP.

Selective reduction of natural killer T cells in the bone marrow of aplastic anaemia

2002 ◽  
Vol 119 (3) ◽  
pp. 803-809 ◽  
Author(s):  
Weihua Zeng ◽  
Jaroslaw P. Maciejewski ◽  
Guibin Chen ◽  
Antonio M. Risitano ◽  
Martha Kirby ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Natural Killer ◽  
Aplastic Anaemia ◽  
Selective Reduction ◽  
Natural Killer T Cells ◽  
Killer T Cells ◽  
Natural Killer T

scholarly journals INDUCTION OF A HEMOLYSIN RESPONSE IN VITRO

1971 ◽  
Vol 133 (6) ◽  
pp. 1325-1333 ◽  
Author(s):  
Klaus-Ulrich Hartmann
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
B Cells ◽  
Close Contact ◽  
Precursor Cells ◽  
Spleen Cells ◽  
High Concentrations ◽  
Thymus Cells ◽  
Bone Marrow Chimeras

Spleen cells of bone marrow chimeras (B cells) and of irradiated mice injected with thymus cells and heterologous erythrocytes (educated T cells) were mixed and cultured together (17). The number of PFC developing in these cultures was dependent both on the concentration of the B cells and of the educated T cells. In excess of T cells the number of developing PFC is linearly dependent on the number of B cells. At high concentrations of T cells more PFC developed; the increase in the number of PFC was greatest between the 3rd and 4th day of culture. Increased numbers of educated T cells also assisted the development of PFC directed against the erythrocytes. It is concluded that the T cells not only play a role during the triggering of the precursor cells but also during the time of proliferation of the B cells; close contact between B and T cells seems to be needed to allow the positive activity of the T cells.

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