Bone marrow cells from allogeneic bone marrow chimeras inhibit the generation of cytotoxic lymphocyte responses against both donor and recipient cells

When added to a mixed lymphocyte culture, bone marrow cells suppress the generation of CTL activity against H-2 Ag shared by the BM cells and the stimulator cells. These cells have been referred to as veto cells and are thought to play a role in maintaining self-tolerance. We analyzed the H-2 specificity of the suppression expressed by the veto cells from H-2 incompatible bone marrow chimeras, because lymphocytes of such chimeras had been shown to be tolerant to both donor and recipient Ag when tested by CTL responses. We found that the bone marrow cells of such chimeras which were featured by non-T and non-B cell characteristics inhibited the generation of CTL directed against either donor or recipient Ag, but not against third-party Ag. These observations suggest that in allogeneic chimeras the veto or veto-like cells alter the inhibitory specificity exhibited in the recipient microenvironment and indicate that these cells are directly involved in the induction and maintenance of self-tolerance.     

Mouse skin graft prolongation with donor strain bone marrow and anti-lymphocyte serum: surface markers of the active bone marrow cells

The survival of C3H/HeJ skin grafts on B6AF1 mice treated with anti-lymphocyte serum (ALS) can be significantly prolonged by the injection of the host with C3H/HeJ bone marrow. Although the prolongation is apparently due at least in part to the ultimate presence in the host of specific suppressor cells of donor origin, little is known about the nature of the cells in the marrow inoculum that are responsible for this effect. The present investigation was undertaken to characterize surface markers of the active bone marrow cells. Marker-positive populations were either depleted and enriched by panning techniques or depleted by killing with specific antibody and complement, and then were assayed for their ability to prolong graft survival. Cells that were adherent to anti-Ia-coated plates extended graft survival only slightly better than did treatment with ALS alone, whereas nonadherent (Ia-depleted) cells, as well as cells treated with anti Ia and complement, retained good prolonging activity. Similarly, panning on anti-immunoglobulin (Ig)-coated plates produced an active, Ig+-depleted population and an inactive adherent population, and killing of Thy-1+ cells with antibody and complement did not compromise the ability of the bone marrow inoculum to prolong graft survival. Complement receptor-positive (EAC+) and Fc gamma receptor-positive cells (EA+) were separated by panning on plates coated with sheep erythrocytes/antibody/complement and erythrocytes/7S antibody respectively. Adherent, EAC+-enriched cells were only slightly active, whereas the nonadherent, EAC-depleted population was fully active in graft prolongation. However, both Fc gamma R+ (EA+)-enriched and depleted populations were active, with the enriched fraction producing significantly better prolongation than the depleted population. Thus, the bone marrow cells that can prolong skin graft survival in ALS-treated mice appear to be Ia-, Thy-1+, largely complement receptor negative, and Ig-, but are largely positive for Fc gamma receptors.     

Osteoblast-related gene expression of bone marrow cells during the osteoblastic differentiation induced by type I collagen

Bone marrow contains multipotent cells that differentiate into fibroblasts, adipocytes, and osteoblasts. Recently we found that type I collagen matrix induced the osteoblastic differentiation of bone marrow cells. Three weeks after cells were cultured with type I collagen, they formed mineralized tissues. In this study, we investigated the expression of osteoblast-related genes (alkaline phosphatase, osteocalcin, bone sialoprotein, osteopontin, and cbfa-1) during the osteoblastic differentiation. The expression of alkaline phosphatase and osteopontin genes increased time-dependently during the osteoblastic differentiation. Osteocalcin and bone sialoprotein genes were expressed in cells that formed mineralized tissues, and both were expressed only after cells reached the mineralized tissue-formation stage. On the other hand, the cbfa-1 gene was expressed from the early differentiation stage. The Asp-Gly-Glu-Ala (DGEA) amino acid domain of type I collagen interacts with the alpha2beta1 integrin receptor on the cell membrane and mediates extracellular signals into cells. When the collagen-integrin interaction was interrupted by the addition of DGEA peptide to the culture, the expression of osteoblastic phenotypes of bone marrow cells was inhibited. These findings imply that the collagen-alpha2beta1 integrin interaction is an important signal for the osteoblastic differentiation of bone marrow cells.     

Expression and function of I region products on immunocompetent cells. II. I region products in T-B interaction.

The anti-Lac B precursor cells from BALB/c (H-2)d mice which survive cytotoxic treatment with anti-Iak and complement will respond to Lac-KLH in culture but require more KLH helper T cells than unselected B cell populations or B cells surviving anti-Ig killing. These findings are not explainable by the classical Poisson assumption of a constant target of T-B ionteraction. We propose a T-B interaction theory with variable Ia target on the B cell surface. The theory quantitatively predicts the observed dose response relationships, and implies that Ia molecules on B cells are cell interaction structures.     

Influence of age on stem cells depends on the sex of the bone marrow donor

Ageing is often accompanied by an increase in bone marrow fat together with reduced bone volume and diseases of the bone such as osteoporosis. As mesenchymal stem cells (MSCs) are capable of forming bone, cartilage and fat tissue, studying these cells is of great importance to understand the underlying mechanisms behind age‐related bone diseases. However, inter‐donor variation has been found when handling MSCs. Therefore, the aim of this study was to investigate the effects of donor age and sex by comparing in vitro characteristics of human bone marrow‐derived MSCs (hBMSCs) from a large donor cohort (n = 175). For this, hBMSCs were analysed for CFU‐F capacity, proliferation, differentiation capacity and surface antigen expression under standardized culture conditions. The results demonstrated a significantly reduced CFU‐F number for hBMSCs of female compared to male donors. Furthermore, there was a significant decrease in the proliferation rate, adipogenic differentiation potential and cell surface expression of SSEA‐4, CD146 and CD274 of hBMSCs with an increase in donor age. Interestingly, all these findings were exclusive to hBMSCs from female donors. Further research should focus on postmenopausal‐related effects on hBMSCs, as the results imply a functional loss and immunophenotypic change of hBMSCs particularly in aged women.     

The bone marrow origin of the cells encapsulating a foreign body in the peritoneal cavity of xenogeneic radiation chimeras]

The origin and ultrastructure of the cells, encapsulating foreign body in peritoneal cavity of xenogeneic (rat in mouse) radiation chimeras was studied. The donor nature of the cells was identified by their karyotype and by DNA hybridization with rat ID-element. Cells with ultrastructural characteristics of fibroblasts encapsulating foreign body in the peritoneal cavity of the xenogeneic radiation chimeras were shown to originate from the transplanted (donor) bone marrow.     

供体骨髓干细胞输注联合肝移植治疗终末期肝病的近期效果观察

目的评价供体骨髓干细胞输注联合肝移植治疗终末期肝病的近期效果。方法2008年3月至2009年1月本中心30例肝移植受者分为两组,实验组8例,行同期供体骨髓干细胞联合肝脏移植;对照组22例,仅行肝脏移植,不行骨髓干细胞输注。观察两组受者术后免疫抑制剂（甲基强的松龙、他克莫司）用量、肝功能（谷氨酸转氨酶、天冬氨酸转氨酶等）变化、急性排斥反应和感染并发症发生情况,以及术后住院时间和费用。采用,检验、方差分析及确切概率法进行统计学分析。结果实验组术后甲基强的松龙总用量和出院时每日他克莫司用量显著低于对照组[甲基强的松龙分别为（1314±105）mg,（1884±256）mg,t=6．060,P=0．000;他克莫司分别为（3．73±0．35）mg／d,（4．93±0．62）mg／d,,=5．147,P=0．000]。术后第1天实验组血清谷氨酸转氨酶、天冬氨酸转氨酶均显著低于对照组[谷氨酸转氨酶分别为（875．2±325．5）IU／L,（1350．4±482．7）IU／L,t=2．543,P=0．016,天冬氨酸转氨酶分别为（646．2±184．9）IU／L,（1021．8±325．4）IU／L,t=3．067,P=0．005]。术后第3天也低于对照组[谷氨酸转氨酶分别为（252．9±35．8）IU／L,（343．5±47．8）IU／L,f=4．866,P=0．000,天冬氨酸转氨酶分别为（227．8±38．0）IU／L,（310．8±61．7）IU／L,t=3．545,P=0．001]。结论同期供体骨髓干细胞联合肝脏移植可以降低术后免疫抑制剂用量,减轻术后早期肝脏损伤,不增加治疗风险,是一种安全有效的治疗方法。     

Linked unresponsiveness: early cytokine gene expression profiles in cardiac allografts following pretreatment of recipients with bone marrow cells expressing donor MHC alloantigen

Linked unresponsiveness operates to induce specific unresponsiveness to fully mismatched vascularized allografts in recipients pretreated with anti-CD4 antibody and syngeneic bone marrow cells expressing a single donor MHC class I alloantigen. The aim of the study was to evaluate early post transplant cytokine expression in allografts where linked unresponsiveness was required for long term graft survival. CBA (H2(k)) mice were pretreated with CBK (H2(k)+K(b)) bone marrow cells under the cover of anti-CD4 antibody 28 days before transplantation of a CBK or a C57BL/10 (H2(b)) cardiac allograft. In both cases graft survival was prolonged (MST=100 days). Intragraft expression for interferon (IFN)-gamma, interleukin (IL)-2, IL-4, IL-10, IL-12(p40), IL-18, iNOS, transforming growth factor (TGF)-beta(1) and C-beta was determined on day 1.5, 3, 7 and 14 after transplantation. Whereas rejecting allografts displayed a sharp peak in IFN-gamma, IL-2, IL-4 and IL-10 expression, non-rejecting allografts were characterized by an initial TGF-beta(1) and IFN-gamma production. An increasing IL-4 expression towards day 14 was a unique feature of linked unresponsiveness. All non-rejecting allografts were characterized by an increasing IL-12(p40) production towards day 14. In summary, the early cytokine expression pattern in allografts after bone marrow induced operational tolerance is influenced by the quantity of donor alloantigens expressed on the graft as well as on the bone marrow inoculum.     

Effect of UV-irradiated donor blood on the colony-forming ability of human bone marrow cells in culture

A possible mechanism of the hemopoiesis stimulation by UV and solar radiation was studied. The UV irradiation of leucocyte-enriched donor serum results in increasing the colony formation activity of the serum. The addition of such a serum but depleted of leucocytes to human bone marrow cells in semisolid agar culture stimulates its colony formation by 1.5-3 times. A serum depleted of leucocytes before the irradiation has not this property. It is supposed that cell surface glycoproteins, desorbing into the serum under UV irradiation, induce the colony formation activity of UV-irradiated blood.     

Interaction of radiation-induced preleukemia cells and bone marrow grafts in C57BL/Ka mice

The repopulation of thymus inoculated with radiation-induced preleukemia cells was studied in 400 R irradiated mice grafted with normal bone marrow cells. These marrow cells gave rise to an actively regenerating thymic progeny, as well as in 400 R treated mice receiving only a bone marrow graft. Moreover, the marrow graft did not prevent the progression of inoculated preleukemic cells towards lymphoma growth.     

Comparative analysis of the spectrum of radiation-induced structural mutations in diploid and tetraploid cells of mouse bone marrow

A comparative analysis of the spectrum of radiation-induced mutations was carried out in diploid mouse bone marrow cells and in tetraploid cells obtained from the latter by means of colchicine treatment. It is established that solitary chromatid deletions prevail among aberrations induced at the G2--S stage. This is the difference of the spectrum of induced chromatid rearrangements in animal cells from that in plant cells. It is assumed that the differences observed are caused by the specificity of supramolecular organization of chromatin in animal and plant cells.     

Ultrastructure of hematopoietic and stromal cells of the subendosteal region of the bone marrow

Using electron microscopic cytochemistry and immunoelectron microscopy, the ultrastructure of bone marrow (BM) cells of the subendosteal region with a high colony-forming (CFUs) ability was studied. In comparison with the central part of BM, the subendosteal region of CBA and BALB/c mice contains a higher number of lymphocyte-like mononuclears, bearing an antigen, common with the brain surface one but negative for peroxidase and acid and alkaline phosphatase. The ultrastructure of these cells is similar to that of presumptive hematopoietic stem cells. In the subendosteal region mononuclears are concentrated with the lower nucleo-cytoplasmic ratio, a feston-like line of the nucleus and more numerous organoids. These cells are characteristic of BM myeloid islands composed of granulocytes being on various stages of differentiation, and of reticular cells positive for alkaline phosphatase.     

Stromal cells of the bone marrow in growing bone

By means of electron microscopy, cytochemistry and radioautography with 3H-thymidine, the bone marrow stromal cells have been studied in the zones of endochondral osteogenesis in the rabbit and rat femoral bones. In the stromal cells demonstrating a high alkaline phosphatase activity are distinguished: perivascular, reticular fibroblastic, osteogenic cells. Populations of the perivascular phosphatase-positive cells include poorly differentiated DNA-synthesizing forms, as well as cells with signs of differentiation into stromal fibroblasts. Cleft-like spaces in cytoplasm of the fibroblastic reticular cells are, probably, formed as a result of lymphocyte-like mononuclears passing through. Phagocyting stromal elements are presented by macrophages, having perivascular localization and including into composition of erythroblastic islets. Mononuclear macrophages are revealed also on the surface of osseous trabecules, where they participate in destruction of hemopoetic and osteogenic cells.     

Effects of T cell depletion in radiation bone marrow chimeras. I. Evidence for a donor cell population which increases allogeneic chimerism but which lacks the potential to produce GVHD

The opposing problems of graft-vs-host disease (GVHD) and failure of alloengraftment present major obstacles to the application of bone marrow transplantation (BMT) across complete MHC barriers. The addition of syngeneic T-cell-depleted (TCD) bone marrow (BM) to untreated fully allogeneic marrow inocula in lethally irradiated mice has been previously shown to provide protection from GVHD. We have used this model to study the effects of allogeneic T cells on levels of chimerism in recipients of mixed marrow inocula. The results indicate that T cells in allogeneic BM inocula eliminate both coadministered recipient-strain and radioresistant host hematopoietic elements to produce complete allogeneic chimerism without clinical GVHD. To determine the role of GVH reactivity in this phenomenon, we performed similar studies in an F1 into parent combination, in which the genetic potential for GVHD is lacking. The presence of T cells in F1 marrow inocula led to predominant repopulation with F1 lymphocytes in such chimeras, even when coadministered with TCD-recipient-strain BM. These results imply that the ability of allogeneic BM cells removed by T cell depletion to increase levels of allochimerism may be mediated by a population which is distinct from that which produces GVHD. These results may have implications for clinical BM transplantation.     

Clonal deletion of self-reactive T cells at the early stage of T cell development in thymus of radiation bone marrow chimeras

Sequential appearance of T cell subpopulations occurs in the thymocytes of irradiated C3H/He mice (H-2k, Mls-1b2a, Thy-1.2) after transplantation with bone marrow cells of AKR/J mice (H-2k, Mls-1a2b, Thy-1.1) (AKR----C3H chimeras). The donor-derived thymocytes of AKR----C3H chimeras on day 14 after bone marrow transplantation (BMT) contained a large number of blastlike CD4+CD8+ cells which represent relatively immature thymocytes, whereas those on day 21 after BMT consisted of small sized CD4+,CD8+ cells which represent a great part in normal thymocytes. To define the developmental stage at which clonal deletion of self-reactive T cells occurs in adult thymus, we followed the fate of V beta 6- or V beta 11-bearing T cells in the donor-derived thymocytes at the early stage of AKR----C3H chimeras. Mature thymocytes expressing high intensity of V beta 6 or V beta 11, which are involved in recognition of Mls-1a or MHC I-E gene products, respectively, were deleted from the donor-derived thymocytes on day 21. Immature thymocytes expressing low intensity of V beta 6 in CD3low thymocyte fraction decreased in proportion, whereas those expressing low intensity of V beta 11 rather increased in proportion in the donor-derived thymocytes of AKR----C3H chimeras from day 14 to day 21 after BMT. These results suggest that the clonal deletion of V beta 6-positive cells occurs just at the stage of immature CD3lowCD4+CD8+ cells, whereas the clonal deletion of V beta 11-positive cells may begin at the transitional stage from CD3lowCD4+CD8+ cells to CD3high single positive cells. Timing of negative selection of thymocytes may vary in distinct T cells capable of recognizing different self-Ag.