IMMUNOREGULATORY ASPECTS AND ROLE OF DONOR NK AND T CELLS AFTER DELAYED DONOR LEUCOCYTE INFUSION IN MINOR ANTIGEN MISMATCHED BONE MARROW CHIMERAS.

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.

Download Full-text

The critical role of T cells in glucocorticoid-induced osteoporosis

Cell Death and Disease ◽

10.1038/s41419-020-03249-4 ◽

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.

Download Full-text

INDUCTION OF A HEMOLYSIN RESPONSE IN VITRO

Journal of Experimental Medicine ◽

10.1084/jem.133.6.1325 ◽

1971 ◽

Vol 133 (6) ◽

pp. 1325-1333 ◽

Cited By ~ 21

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.

Download Full-text

The role of the Th1 transcription factor T-bet in a mouse model of immune-mediated bone-marrow failure

Blood ◽

10.1182/blood-2009-03-211383 ◽

2010 ◽

Vol 115 (3) ◽

pp. 541-548 ◽

Cited By ~ 22

Author(s):

Yong Tang ◽

Marie J. Desierto ◽

Jichun Chen ◽

Neal S. Young

Keyword(s):

Bone Marrow ◽

T Cells ◽

Transcription Factor ◽

Transforming Growth Factor ◽

Bone Marrow Failure ◽

Critical Role ◽

Interferon Γ ◽

Interleukin 17 ◽

Immune Mediated

Abstract The transcription factor T-bet is a key regulator of type 1 immune responses. We examined the role of T-bet in an animal model of immune-mediated bone marrow (BM) failure using mice carrying a germline T-bet gene deletion (T-bet−/−). In comparison with normal C57BL6 (B6) control mice, T-bet−/− mice had normal cellular composition in lymphohematopoietic tissues, but T-bet−/− lymphocytes were functionally defective. Infusion of 5 × 106 T-bet−/− lymph node (LN) cells into sublethally irradiated, major histocompatibility complex–mismatched CByB6F1 (F1) recipients failed to induce the severe marrow hypoplasia and fatal pancytopenia that is produced by injection of similar numbers of B6 LN cells. Increasing T-bet−/− LN-cell dose to 10 to 23 × 106 per recipient led to only mild hematopoietic deficiency. Recipients of T-bet−/− LN cells had no expansion in T cells or interferon-γ–producing T cells but showed a significant increase in Lin−Sca1+CD117+CD34− BM cells. Plasma transforming growth factor-β and interleukin-17 concentrations were increased in T-bet−/− LN-cell recipients, possibly a compensatory up-regulation of the Th17 immune response. Continuous infusion of interferon-γ resulted in hematopoietic suppression but did not cause T-bet−/− LN-cell expansion or BM destruction. Our data provided fresh evidence demonstrating a critical role of T-bet in immune-mediated BM failure.

Download Full-text

The enigma of tolerance and chimerism: variable role of t cells and chimerism in induction of tolerance with bone marrow

Transplantation Proceedings ◽

10.1016/s0041-1345(01)02625-2 ◽

2001 ◽

Vol 33 (7-8) ◽

pp. 3837-3839 ◽

Cited By ~ 6

Author(s):

A.P. Monaco ◽

T. Maki ◽

D. Hale ◽

A. Umemura ◽

H. Morita

Keyword(s):

Bone Marrow ◽

T Cells ◽

Induction Of Tolerance

Download Full-text

Regulation of Microglia by CD4+ and CD8+ T Cells: Selective Analysis in CD45-congenic Normal and Toxoplasma gondii-infected Bone Marrow Chimeras

Brain Pathology ◽

10.1111/j.1750-3639.2001.tb00380.x ◽

2006 ◽

Vol 11 (1) ◽

pp. 44-55 ◽

Cited By ~ 18

Author(s):

Dirk Schlüter ◽

Timothy Meyer ◽

Andreas Strack ◽

Sabine Reiter ◽

Marianne Kretschmar ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

Toxoplasma Gondii ◽

Cd8 T Cells ◽

Bone Marrow Chimeras ◽

Selective Analysis

Download Full-text

Effects of B7.2−/− Mature Dendritic Cells on Tolerance Induction to Alloantigens in Fetal Mice Following In Utero Transplantation with Lineage Depleted Bone Marrow.

Blood ◽

10.1182/blood.v104.11.2134.2134 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2134-2134

Author(s):

Swati Bhattacharyya ◽

Morton J. Cowan

Keyword(s):

Bone Marrow ◽

T Cells ◽

Dendritic Cells ◽

Stem Cell ◽

In Utero ◽

Relative Role ◽

Skin Grafts ◽

Hematopoietic Stem ◽

Fetal Mice

Abstract In utero hematopoietic stem cell transplantation (IUT) has the potential to cure a variety of marrow stem cell defects without using marrow ablative therapy. However IUT for diseases other than SCID has been unsuccessful. To better understand the barriers to successful IUT we wanted to define the role of the B7.1/B7.2 co-stimulatory molecules in inducing tolerance to allogeneic donor bone marrow cells in the fetal murine recipient. We studied the relative role of B7.1 and B7.2 expression on dendritic cells (DC) on engraftment and in generating donor specific tolerance in fetal mice. Mature DC (mDC) from B7.1−/− or B7.2−/− donors and wild type (wt) lineage depleted (lin−) C57Bl/6 (B6) bone marrow (BM) were injected into gestational day (GD) 14 Balb/c fetuses. Recipients of lin− wt BM and B7.1−/− mDC had a significantly lower survival (47.4%, p<0.01) associated with mild-moderate GvHD compared to the recipients of B7.2−/− mDC and lin− BM (82.3%) where none developed GvHD. Engraftment results in blood at 6 weeks post IUT showed, B7.1−/− recipients had multilineage engraftment (4.7±0.8% T cells and 5.7± 1.1% granulocytes) in their blood, but by 12 weeks, only donor CD3+ (predominantly CD8+) cells (2.1±1.3%) were present. The percent H2Kb+ (donor) T cells (predominantly CD4+) in the blood of recipients of lin− wt BM and B7.2−/− was 11.8±8.5% at 6 weeks p<0.001 and 6.5±2.5% at 12 weeks, p=0.006. The circulating donor CD4+ cells were Th2 (CD4+CD25−IL4+IL10+) and Treg (CD4+CD25+IL4−IL10−). Both fractions inhibited the T cell proliferative response in the MLR. Long term engraftment in thymic tissues was found in the tolerant recipients of lin− wt BM and B7.2−/− mDC (13.4±8.3% donor CD3+ T cells). We also found prolonged (rejection by day 36) acceptance of donor skin grafts in 7 of 12 recipients of B7.2−/− mDC and 2 of 5 recipients of B7.2−/− mDC and lin−BM. All third party C3H grafts were rejected by day 14 and 80% of the Balb/c (self) skin grafts were permanently accepted. We hypothesized that tolerized animals would behave similarly to recipients of megadoses of syngeneic BM with an increase in multilineage engraftment. We injected a total of 200x106 male wt B6 lin− BM cells over 5 days into adult IUT recipients of B7.1−/− or B7.2−/− mDC ± lin− wt BM and wt age-matched allogeneic and syngeneic (female) controls. Mice that had received B7.2−/− mDC + lin− BM in utero showed multi-lineage engraftment in the blood. In contrast, the in utero recipients of B7.1−/− mDC + lin− BM showed no significant engraftment (p<0.05). In conclusion, donor DC costimulatory molecules significantly affect survival, engraftment and GvHD; and these responses to B7.2−/− mDC and lin− BM appear to be mediated by both Th2 and Treg donor cells.

Download Full-text

The Role of ERK5 Signaling in Tolerance Induction by Veto CTLs.

Blood ◽

10.1182/blood.v106.11.3302.3302 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3302-3302

Author(s):

Shlomit Reich-Zeliger ◽

Tamar Hanoch ◽

Rony Seger ◽

Yair Reisner

Keyword(s):

Bone Marrow ◽

T Cells ◽

Cellular Systems ◽

Class I ◽

Spleen Cells ◽

Effector Cells ◽

Cd8 Cells ◽

Veto Cells ◽

Specific Inhibitors

Abstract Several bone marrow cells and lymphocyte subpopulations, known as ‘veto cells’, were shown to induce transplantation tolerance across major histocompatibility antigens. Recently, it has been suggested that anti-3rd party CTLs depleted of alloreactivity against the host are endowed with marked veto activity and can facilitate bone marrow allografting. The veto mechanism is still obscure. While early studies emphasized the role of CD8 mediated apoptosis, we showed that the veto activity of anti-3rd party CD8+ CTLs is dependent upon the simultaneous expression of both CD8 and FasL. Thus, it seems that although Fas is upregulated on the effector T cells upon engagement of their TCR by class I of the veto cells, the presence of FasL on the veto cells cannot result in apoptosis of the effector cells unless CD8 on the veto cells is available and can interact with class 1 on the effector cells. Thus, the interaction of CD8 on the veto cells with class I on the effector cells seems to be associated with an increased susceptability of the effector cells to FasL killing. To further delineate the mechanism of the veto effect we have now studied the role of different signaling pathways using specific inhibitors. Spleen CD8 T cells from 2C mice (H2b) bearing TCR transgene directed against (H2d) were used as effector cells and anti FVB (H2q, third party) CTLs generated from Balb/c spleen cells (H2d) were used as veto cells. The addition of the latter cells to MLR of 2C against Balb/c (H2d) simulators, leads to deletion of the 2C effector CD8 cells within 72 hrs. Deletion monitored by FACS analysis of cells stained with anti-TCR transgene antibody (1B2+) revealed reduction from 46%±11% 1B2+CD8+ cells to 6%±3% 1B2+CD8+ cells in 6 different experiments. In contrast, veto CTLs generated from SJL (H2s) spleen cells that do not display the H2 recognized by the 2C effector cells, did not result in a significant deletion of the effector cells (42%±12% 1B2+CD8+ cells in 6 different experiments). The specific deletion exhibited by veto CTLs of Balb/c origin, can be inhibited by MEK1/2/5 inhibitors such as U0126, reducing the veto activity from 85.5%±7% to 16%±14% in 6 different experiments. The effective concentration of U0126 was relatively high (10μM), and lower concentration of this drug (1μM) had no response, indicating a potential involvement of the MEK5/ERK5 cascade rather than the MEK1/2-ERK1/2 cascade, in the veto effect. In addition, no inhibition of veto activity could be found with specific inhibitors of other signaling molecules such as JNK, P38, PI3K or PKC. Considering that Fas expression on the effector cells is critical for the veto activity, it is interesting that the ERK inhibitor didn’t affect the level of Fas on the effectors (93%±3% of 1B2+CD8+ upregulate FAS in the presence of U0126 in 7 different experiments). Also, this inhibition is not likely mediated by affecting the veto CTLs, as pretreatment of the latter cells with ERK inhibitor didn’t diminish the veto effect. The pro-apoptotic effects of MEK5-ERK5 cascade in this system is intriguing because these kinases are usually thought to promote proliferation and survival in most cellular systems. Therefore, the veto cells exhibit a unique signaling system, which utilizes ERK5 cascade to induce apoptosis. Further studies are directed at the potential links between the ERK5 cascade, the Fas system and the rest of the apoptotic machinery.

Download Full-text

Role of Il-2, Il-7, and IL-15 in T Cell Mediated Graft-vs-Leukemia Against Human Acute Lymphoblastic Leukemia in a NOD/scid Chimeric Mouse Model.

Blood ◽

10.1182/blood.v106.11.5256.5256 ◽

2005 ◽

Vol 106 (11) ◽

pp. 5256-5256

Author(s):

Doug Cipkala ◽

Kelly McQuown ◽

Lindsay Hendey ◽

Michael Boyer

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

T Cells ◽

Mouse Model ◽

Scid Mouse ◽

In Vitro Cytotoxicity ◽

Scid Mouse Model

Abstract The use of cytotoxic T-lymphocytes (CTL) has been attempted experimentally with various tumors to achieve disease control. Factors that may influence GVT include CTL cytotoxicity, ability to home to disease sites, and survival of T cells in the host. The objective of our study is to evaluate the GVL effects of human alloreactive CTL against ALL in a chimeric NOD/scid mouse model. CTL were generated from random blood donor PBMCs stimulated with the 697 human ALL cell line and supplemented with IL-2, -7, or -15. CTL were analyzed for in vitro cytotoxicity against 697 cells, phenotype, and in vitro migration on day 14. NOD/scid mice were injected with 107 697 ALL cells followed by 5x106 CTL. Mice were sacrificed seven days following CTL injection and residual leukemia was measured in the bone marrow and spleen via flow cytometry. The ratios of CD8/CD4 positive T cells at the time of injection were 46/21% for IL-2, 52/31% for IL-7, and 45/14% for IL-15 cultured CTL (n=13). Control mice not receiving CTL had a baseline leukemia burden of 2.01% and 0.15% in the bone marrow and spleen, respectively (n=15). Mice treated with IL-15 cultured CTL had a reduction in tumor burden to 0.2% (n=13, p=0.01) and 0.05% (n=13, p=0.01) in bone marrow and spleen, respectively. Those treated with IL-2 or IL-7 cultured CTL showed no significant difference in leukemia burden in either the bone marrow (IL-2 1.28%, Il-7 5.97%) or spleen (IL-2 0.4%, IL-7 0.33%). No residual CTL could be identified in the bone marrow or spleen at the time of sacrifice in any CTL group. CTL grown in each cytokine resulted in similar in vitro cytotoxicity at an effector:target ratio of 10:1 (IL-2 41.3%, IL-7 37.7%, IL-15 45.3%, n=12–15, p>0.05 for all groups) and had statistically similar intracellular perforin and granzyme-B expression. In vitro CTL migration to a human mesenchymal stem cell line was greatest with IL-15 CTL (30.5%, n=4), followed by IL-7 CTL (18.9%, n=4), and least in IL-2 CTL (17.9%, n=4), though the differences were not significant. In vitro CTL migration was analyzed to an SDF-1α gradient as CXCR4/SDF-1α interactions are necessary for hematopoietic progenitor cell homing to the bone marrow. IL-15 cultured CTL showed the highest migration (48.8%, n=8) as compared to IL-2 (21.7%, n=6, p=0.048) or IL-7 CTL (35.9%, n=8, p>0.05). However, surface expression of CXCR4 measured by flow cytometry was significantly higher in IL-7 CTL (89.4%, n=9) compared to IL-2 CTL (52.2%, n=9, p<0.001) and IL-15 CTL (65.4%, n=10, p=0.002). Experiments are currently underway to further evaluate the role of CXCR4/SDF-1α in GVL. Preliminary in vivo experiments do not suggest any significant differences in CTL engraftment when evaluated at 24 hours post injection. Expression of the anti-apoptotic bcl-2 protein was greatest on IL-7 (MFI=5295, n=13) and IL-15 (MFI=4865, n=14) when compared to IL-2 CTL (MFI=3530, n=13, p=0.02 vs. IL-7, p=0.05 vs. IL-15), suggesting an increased in vivo survival ability. We hypothesize that IL-15 cultured CTL have greater GVL effects due to either higher in vivo survival, greater bone marrow homing efficiency, or both. Future experiments are planned to evaluate in vivo administration of IL-2 to enhance CTL survival in the host. In conclusion, IL-15 cultured CTL had significantly greater in vivo GVL effects compared to IL-2 and IL-7 CTL in the NOD/scid mouse model. This model can be utilized to evaluate the mechanism of T cell mediated GVL against ALL and potentially other human malignancies.

Download Full-text

Allogeneic Environment and Tissue Damage Provide Critical Stimuli for Regulatory T Cell Expansion and Survival In Vivo after Hematopoietic Cell Transplantation.

Blood ◽

10.1182/blood.v108.11.1731.1731 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1731-1731

Author(s):

Vu H. Nguyen ◽

Daisy Chang ◽

Robert S. Negrin

Keyword(s):

Bone Marrow ◽

T Cells ◽

Tissue Damage ◽

Hematopoietic Cell Transplantation ◽

Critical Role ◽

Lymphoid Organs ◽

Gamma Chain ◽

Secondary Lymphoid Organs

Abstract CD4+CD25+ regulatory T cells (Treg) mediate alloresponses in murine models of bone marrow transplantation (BMT), leading to protection from graft-versus-host disease (GvHD). However, in vivo migration and tissue localization of Treg during this inflammatory response remain unclear. We previously demonstrated co-localization of Treg with effector T cells (Tcon) with initial expansion in secondary lymphoid organs prior to migration into inflamed tissues in a major MHC-mismatched BMT model. To explore the stimuli for Treg proliferation, we evaluated the role of the allogeneic environment by transferring FVB donor luciferase-expressing (luc+) Treg into lethally-irradiated syngeneic recipients. Unlike the allogeneic irradiated setting where Treg expand in the presence or absence of Tcon, adoptively transferred luc+ Treg were not detected in secondary lymphoid organs of syngeneic lethally-irradiated BMT recipients by in vivo bioluminescence imaging (BLI). Syngeneic luc+ Tcon also had significantly different in vivo dynamics, with a 4 day delay and only moderate expansion in lymph nodes. Proliferation was not detected in the spleen, unlike their allogeneic Tcon counterparts, nor in the bone marrow compartments, as seen in lymphopenic models. To assess whether irradiation induced the observed in vivo dynamics of Treg in the allogeneic setting, we transferred FVB luc+ Treg or luc+ Tcon into unirradiated Balb/c Rag2−/−gamma chain (γC) −/− recipients, which lack T, B, and NK cells. After adoptive transfer into Rag2−/−γC−/− recipients, robust Tcon proliferation was observed in secondary lymphoid organs and the bone marrow compartments; however, Treg expansion was weak, and specific localization to lymphoid or nonlymphoid tissues was not observed. Treg were stimulated to localize to and expand in secondary lymphoid organs by the co-transfer of Tcon in unirradiated Rag2−/− (γC) −/− or by conditioning Rag2−/− (γC) −/− recipients with irradiation. Exogenous IL2 administration two weeks following luc+ Treg transfer into unirradiated Rag2−/− (γC) −/− recipients similarly led to localization and expansion of Treg in secondary lymphoid organs. These studies indicate the critical role of proinflammatory cytokines, such as IL2, generated either by irradiation-induced tissue damage or donor Tcon, in the expansion and localization of Treg. Differences between Tcon and Treg expansion in syngeneic or unconditioned allogeneic Rag2−/− γC−/− hosts suggest an important role of conditioning with irradiation alone or in concert with the allogeneic environment, in providing distinct signals for Tcon versus Treg activation, proliferation, and localization.

Download Full-text