Visualization of immune response kinetics in full allogeneic chimeras.

Background: Donor Lymphocyte Infusion (DLI) is a well-recognized tool for augmentation of the anti-leukemia effect after mismatched bone marrow transplantation. Experimental results show, however, that DLI efficacy is strongly dependent on the number of donor hematopoietic cells persisting in recipient after transplantation. It is strong in mixed chimeras and relatively weak in full chimeras (FC) that replace host antigen-presenting cells by donor antigen-presenting cells.

Analysis of adenoviral attachment to human platelets.

Background: Systemic adenoviral (Ad) vector administration is associated with thrombocytopenia. Recently, Ad interaction with mouse platelets emerged as a key player determining liver uptake and platelet clearance. However, whether Ad can activate platelets is controversial.

Prevention of acute graft-vs-host disease by a single low-dose cyclophosphamide injection following allogeneic bone marrow transplantation.

Objective: Previously, we documented that conditioning based on donor-specific cell transfusion (DST) and subsequent selective depletion of activated donor-reactive cells by cyclophosphamide (CY) facilitates alloengraftment in a murine transplantation model. Transplantation event represents a strong immunogenic stimulus for host-reactive donor T cells that induce graft-vs-host disease (GVHD). Therefore, in this study, we addressed the question of whether a single posttransplantation CY administration (CY2) can prevent acute GVHD-related mortality without compromising engraftment of allogeneic transplant.

A novel dynamic matrix detachment model reveals a shift from apoptosis to necrosis in melanoma cells.

Anchorage-independence is a hallmark of invasive cancer. The setback of the classical poly-HEMA static matrix detachment (SMD) anoikis model is the absence of dynamic fluid circulation, resulting in cell aggregates. We addressed this problem by developing a novel 3D cell culture dynamic matrix detachment (DMD) model with a turbulent-free laminar flow, yielding a very low shear stress.

Mesenchymal stromal cells lose their immunosuppressive potential after allotransplantation.

Objective: The stem cell fraction of mesenchymal stromal cells (MSCs) is capable of self-renewal and under inductive conditions differentiates into bone, cartilage, hematopoietic stroma, and other mesenchymal tissues. Therefore, MSCs represent a promising source for hard tissue repair therapies. MSCs are also immunosuppressive and prevent activation of allogeneic lymphocytes in vitro.

Pancreatic acinar and islet cell infection by low-dose SV40 administration.

Objectives: Viral vector uptake into the pancreas is rare. The few viral vectors reported to transduce in vivo pancreatic islets after systemic injection required additional physical measures, such as direct pancreatic injection or hepatic vessel clamping. Because pancreatic islet uptake of the human polyomavirus family member BK virus was previously reported in hamsters after systemic administration, we hypothesized that SV40, a polyomavirus member remarkably similar to BK virus, may also infect the pancreas.

A 3D rotary renal and mesenchymal stem cell culture model unveils cell death mechanisms induced by matrix deficiency and low shear stress.

Background: In epithelial and endothelial cells, detachment from the matrix results in anoikis, a form of apoptosis, whereas stromal and cancer cells are often anchorage independent. The classical anoikis model is based on static 3D epithelial cell culture conditions (STCK).

Methods: We characterized a new model of renal, stromal and mesenchymal stem cell (MSC) matrix deprivation, based on slow rotation cell culture conditions (ROCK).

Depletion of donor-reactive cells as a new concept for improvement of mismatched bone marrow engraftment using reduced-intensity conditioning.

Objective: New nonmyeloablative strategies to improve acceptance of mismatched bone marrow (BM) may compensate for the inadequate supply of compatible grafts. Recently we proposed to facilitate engraftment of mismatched BM by selective depletion of activated donor-reactive host cells with cyclophosphamide (CY). Here we have compared engraftment of allogeneic BM after depletion of antigen-activated host lymphocytes by CY, with BM engraftment following general immunosuppression by the same CY dose.

Depletion of alloantigen-primed lymphocytes overcomes resistance to allogeneic bone marrow in mildly conditioned recipients.

Objective: Successful implantation of allogeneic bone marrow (BM) cells after nonmyeloablative conditioning would allow to compensate for the inadequate supply of compatible grafts and to reduce mortality of graft-vs.-host disease (GVHD). Recently, we proposed to facilitate engraftment of mismatched BM by conditioning for alloantigen-primed lymphocyte depletion (APLD) with cyclophosphamide (CY).

Prevention of diabetes in nonobese diabetic mice by nonmyeloablative allogeneic bone marrow transplantation.

Objective: Autoimmune diabetes in nonobese diabetic (NOD) mice can be prevented by allogeneic bone marrow transplantation (BMT) from diabetes-resistant murine strains. Donor-specific tolerance can also be induced by BMT; however, clinical application of nonmyeloablative conditioning prior to BMT may be essential for reducing transplant-related toxicity and mortality. In this study, we have attempted to treat autoimmunity using a new nonmyeloablative regimen for BMT.

CD40 ligand-specific antibodies synergize with cyclophosphamide to promote long-term transplantation tolerance across MHC barriers but inhibit graft-vs-leukemia effects of transplanted cells.

Objectives: We previously demonstrated that allogeneic bone marrow transplantation (BMT) after low-dose total lymphoid irradiation (200 cGy) and depletion of donor-reactive cells with cyclophosphamide (Cy) converted recipients to graft-vs-host disease (GVHD)-free chimeras tolerant to donor skin grafts. BMT also generated strong graft-vs-leukemia (GVL) response. However, clinical application of the protocol was hampered by the requirement for a relatively high dose of Cy (200 mg/kg).

Nonmyeloablative allogeneic bone marrow transplantation as immunotherapy for hematologic malignancies and metastatic solid tumors in preclinical models.

Objective: We previously demonstrated that a combination of mild total lymphoid irradiation (TLI) with selective depletion of the host's donor-reactive cells allows for stable and graft-vs-host disease (GVHD)-free engraftment of allogeneic bone marrow (BM). In this study, we investigated the efficacy of this nonmyeloablative strategy for BM transplantation (BMT) as immunotherapy for minimal residual disease.

Materials And Methods: BALB/c mice inoculated with leukemia (BCL1) or breast carcinoma (4T1) cells were conditioned for BMT with TLI (200 cGy) followed by priming with donor (C57BL/6) BM cells on day 1, and by injection with 200 mg/kg cyclophosphamide on day 2.