Decreased graft-versus-host disease after haplotype mismatched bone marrow allografts in miniature swine following interleukin-2 treatment

Animal models of chemotherapy-induced mucositis: translational relevance and challenges

Chemotherapy for cancer patients induces damaging tissue reactions along the epithelium of the gastrointestinal tract (GIT). This chemotherapy-induced mucositis (CIM) is a serious side effect of cytotoxic drugs, and several animal models of CIM have been developed, mainly in rodents and piglets, to help understand the progression of CIM and how to prevent it. Animal models allow highly controlled experimental conditions, detailed organ (e.g., GIT) insights, standardized, clinically relevant treatment regimens, and discovery of new biomarkers. Still, surprisingly few results from animal models have been translated into clinical CIM management and treatments. The results obtained from specific animal models can be difficult to translate to the diverse range of CIM manifestations in patients, which vary according to the antineoplastic drugs, dose, underlying (cancer) disease, and patient characteristics (e.g., age, genetics, and body constitution). Another factor that hinders the direct use of results from animals is inadequate collaboration between basic science and clinical science in relation to CIM. Here, we briefly describe CIM pathophysiology, particularly the basic knowledge that has been obtained from CIM animal models. These model studies have indicated potential new preventive and ameliorating interventions, including supplementation with natural bioactive diets (e.g., milk fractions, colostrum, and plant extracts), nutrients (e.g., polyunsaturated fatty acids, short-chain fatty acids, and glutamine), and growth factor peptides (e.g., transforming growth factor and glucagon-like peptide-2), as well as manipulations of the gut microbiota (e.g., prebiotics, probiotics, and antibiotics). Rodent CIM models allow well-controlled, in-depth studies of animals with or without tumors while pig models more easily make clinically relevant treatment regimens possible. In synergy, animal models of CIM provide the basic physiological understanding and the new ideas for treatment that are required to make competent decisions in clinical practice.

Stability of the recombinant anti‑erbB2 scFv‑Fc‑interleukin‑2 fusion protein and its inhibition of HER2‑overexpressing tumor cells

The anti‑erbB2 scFv‑Fc‑IL‑2 fusion protein (HFI) is the basis for development of a novel targeted anticancer drug, in particular for the treatment of HER2‑positive cancer patients. HFI was fused with the anti‑erbB2 antibody and human IL‑2 by genetic engineering technology and by antibody targeting characteristics of HFI. IL‑2 was recruited to target cells to block HER2 signaling, inhibit or kill tumor cells, improve the immune capacity, reduce the dose of antibody and IL‑2 synergy. In order to analyse HFI drug ability, HFI plasmid stability was verified by HFI expression of the trend of volume changes. Additionally, HFI could easily precipitate and had progressive characteristics and thus, the buffer system of the additive phosphate‑citric acid buffer, arginine, Triton X‑100 or Tween‑80, the establishment of a microfiltration, ion exchange, affinity chromatography and gel filtration chromatography‑based purification process were explored. HFI samples were obtained according to the requirements of purity, activity and homogeneity. In vivo, HFI significantly delayed HER2 overexpression of non‑small cell lung cancer (Calu‑3) in human non‑small cell lung cancer xenografts in nude mice, and the inhibition rate was more than 60% (P<0.05) in the group treated with 1 mg/kg the HFI dose; HFI significantly inhibited HER2 expression of breast cancer (FVB/neu) transgenic mouse tumor growth in 1 mg/kg of the HFI dose group, and in the following treatment the 400 mm3 tumors disappeared completely. Combined with other HFI test data analysis, HFI not only has good prospects, but also laid the foundation for the development of antibody‑cytokine fusion protein‑like drugs.

A glucocorticoid amplifies IL-2-induced selective expansion of CD4(+)CD25(+)FOXP3(+) regulatory T cells in vivo and suppresses graft-versus-host disease after allogeneic lymphocyte transplantation

Regulatory T (Treg) cells are a subpopulation of T cells that not only prevent autoimmunity, but also control a wide range of T cell-dependent immune responses. Glucocorticoid treatment (dexamethasone, or Dex) has been reported to amplify IL-2-mediated selective in vivo expansion of Treg cells. We simultaneously administered Dex and IL-2 to the donor in a murine allogeneic lymphocyte transplantation model to expand functional suppressive CD4(+)CD25(+)FOXP3(+) T cells in the graft and to raise the regulatory T cell/effector T cell (Treg/ Teff ) ratio to prevent graft-versus-host disease (GVHD). After combined treatment of the donor with Dex (5 mg/kg/day) and IL-2 (300,000 IU/mouse/day) for 3 days, grafts were subjected to flow cytometric analysis, and transplantation was carried out from male C57BL/6 mice to female BALB/c mice aged 8-12 weeks. Results showed that short-term simultaneous administration of Dex and IL-2 markedly expanded functional suppressive CD4(+)CD25(+)FOXP3(+) T cells in the murine spleen. In this murine allogeneic transplantation model, the grafts from donors with Dex and IL-2 pre-treatment led to a longer survival time for the recipients than for the control group (median survival time > 60 day vs. 12 day, P=0.0002). The ratio of Treg/Teff also increased remarkably (0.43+/-0.15 vs. 0.14+/-0.01, P=0.01). This study demonstrated that co-stimulation with Dex and IL-2 selectively expanded functional CD4(+)CD25(+)FOXP3(+) T cells in vivo, and that grafts from donors pre-treated with Dex and IL-2 led to longer survival time and greater suppression of GVHD after allogeneic transplantation. Thus, GVHD can be suppressed by the specific expansion of regulatory T cells with Dex and IL-2 in graft donors.

Immunological Unresponsiveness in Chimeric Miniature Swine following MHC-Mismatched Spleen Transplantation

BACKGROUND

In rodents, spleen allotransplantation (SpTx) induces tolerance. We investigated the induction of chimerism and donor-specific unresponsiveness following pig SpTx.

METHODS

Thirteen pigs underwent splenectomy (day 0); all received a blood transfusion. In 11/13 pigs, SpTx was performed across a MHC class I (n=1) or full (n=10) barrier; two control pigs received no SpTx. All pigs were monitored for chimerism, and anti-donor immune responses, including suppressor assays. Four pigs (two asplenic controls and two with SpTx) underwent delayed donor-matched kidney transplantation without immunosuppression.

RESULTS

Six of the 11 spleen grafts were lost from rejection (n=5) or splenic vein thrombosis (n=1), and five remained viable. All 11 SpTx recipients developed multilineage chimerism, but chimerism was rapidly lost if the graft failed. Two control pigs showed <6% blood chimerism for 4 and 11 days only. Pigs with functioning spleen grafts had multilineage chimerism in blood, thymus and bone marrow for at least 2-6 months, without graft-versus-host disease. These pigs developed in vitro donor-specific hyporesponsiveness and suppression. In 2 pigs tolerant to the spleen graft, donor MHC-matched kidney grafts survived for >4 and >7 months in the absence of exogenous immunosuppression; in two asplenic pigs, kidney grafts were rejected on days 4 and 15.

CONCLUSIONS

Successful SpTx can result in hematopoietic cell engraftment and in vitro donor-specific unresponsiveness, enabling prolonged survival of subsequent donor-matched kidney grafts without immunosuppression.

The safety of interferon-?-1b therapy for invasive fungal infections after hematopoietic stem cell transplantation

BACKGROUND

The restoration of normal immune responses, especially of the T-helper type 1 immune response, is an important predictor of fungal infection outcome in patients with malignant disease who undergo hematopoietic stem cell transplantation (HSCT). The authors sought to evaluate the safety of adjuvant recombinant interferon-gamma-1b as an immune-modulatory therapy HSCT recipients.

METHODS

Thirty-two patients received interferon-gamma-1b after undergoing HSCT at the author's institution between 1998 and 2003. A retrospective analysis was undertaken after obtaining permission from the Institutional Review Board.

RESULTS

Twenty-six of 32 patients (81%) received allogeneic stem cell grafts. All but 1 patient received interferon-gamma-1b and antifungals to treat infections; the other patients received interferon-gamma-1b to promote autologous graft-versus-tumor effect. Interferon-gamma-1b usually was administered at a dose of 50 mug subcutaneously every other day. The median duration (+/- standard deviation) of interferon-gamma-1b therapy was 6+/-6.5 doses (range, 1-29 doses), and the median cumulative dose was 487+/-453 mug (range, 35-2175 microg). During therapy with interferon-gamma-1b, fever was common (n=9 patients; 28%). In 1 patient (3%), new-onset lymphocytopenia occurred but resolved after cytokine therapy was discontinued; there were no interferon- gamma-1b-related episodes of neutropenia, thrombocytopenia, anemia, or liver dysfunction. Interferon-gamma-1b therapy did not precipitate or exacerbate acute or chronic graft-versus-host disease (GVHD). In fact, in 2 of 7 patients (29%) with acute GVHD and in 3 of 10 patients (30%) with chronic GVHD, significant improvements in GVHD were noted during therapy with interferon-gamma-1b. Among the 26 patients with aspergillosis, 14 patients (54%) died. However, 5 of 10 patients (50%) with presumed pulmonary aspergillosis, 3 of 9 patients (33%) with probable pulmonary aspergillosis, 1 of 2 patients (50%) with definite pulmonary aspergillosis, and 3 of 5 patients (60%) with disseminated aspergillosis responded to antifungals and adjuvant interferon-gamma-1b.

CONCLUSIONS

Recombinant interferon-gamma-1b was tolerated without serious adverse reactions in HSCT recipients. A large, prospective, randomized study will be needed to evaluate the efficacy of this cytokine in high-risk HSCT recipients who have invasive mycoses.

Engraftment of quiescent progenitors and conversion to full chimerism after nonmyelosuppressive conditioning and hematopoietic cell transplantation in miniature swine

Our laboratory has previously reported a nonmyelosuppressive preparative regimen for hematopoietic cell transplantation that leads to mixed chimerism and allograft tolerance in miniature swine across minor and major histocompatibility disparities. Stable chimerism persisted in most of these animals but was restricted to T cells and confined to peripheral blood. Because of the importance of myeloid and erythroid progenitors for the treatment of hematologic disorders, the objective of this study was to assess whether such cells existed in the bone marrow of these lymphoid chimeras as an indication of functional engraftment. Colony-formation assays were performed on donor inocula before infusion and on bone marrow cells harvested from the transplant recipients. Donor-origin myeloid/erythroid progenitor colonies were detected in bone marrow from 6 of 7 lymphoid chimeric recipients. A delayed donor leukocyte infusion successfully converted a stable lymphoid chimera to full multilineage chimerism within 2 weeks. Donor-origin myeloid/erythroid progenitors could be detected in the bone marrow of a host-matched recipient after myeloablation and adoptive transfer of mobilized cells from one of the engrafted lymphoid chimeras. These data suggest that even when only lymphoid chimerism is readily detected by flow cytometry, dormant myeloid/erythroid progenitors can exist and subsequent conversion to full donor chimerism can be achieved. The ability to establish multilineage engraftment and chimerism without significant toxicity may have important clinical implications for the management of nonmalignant hematopoietic disorders and hematologic malignancies.

Model for experimental revascularized laryngeal allotransplantation

BACKGROUND

Although a human laryngeal transplant has been undertaken successfully, important questions remain that require a suitable animal model.

METHODS

A pig model for allotransplantation has been developed. Organ perfusion was studied in nine animals before four transplants were performed in congenic (unrecovered) animals and eight in unmatched (recovered) animals. Larynges were regularly examined endoscopically until death at 14 days. Immunosuppression included the use of tacrolimus. Revascularization was achieved by anastomosing the donor right cervical vascular tree to the recipient common carotid. In recovered animals, four allografts were placed orthotopically and four heterotopically.

RESULTS

The pig larynx was perfused adequately via the right cervical vascular tree and congenic grafts were well tolerated. Of eight allografts, seven were well tolerated and remained healthy for the duration of the study (14 days). One allograft became infected between days 4 and 7 after operation. Median operating time was 6 h, with a median cold ischaemia time of 3 h.

CONCLUSION

Revascularized allotransplants of the larynx can be undertaken reliably in pigs and this provides a preclinical model for studies of laryngeal transplantation.

Cytokines in graft-versus-host disease and the graft-versus-leukemia reaction

Graft-versus-host disease (GVHD) is the major complication after allogeneic hemopoietic stem cell transplantation. GVHD is destructive by itself and sets the stage for other sequelae, in particular, overwhelming infections. Recent investigations have improved our understanding of the underlying pathophysiology of GVHD. There are now compelling data on the role of host tissue destruction as the initial insult, extensive interactions of cellular donor and host components, a complex network of cytokines, adhesion molecules, and other components in the development of GVHD. The improved understanding of interactions among various signals is likely to allow for the development of new prophylactic strategies. A review of the data shows, however, that results are very dependent upon the models used. It is difficult or impossible to separate completely the discussion of cytokines that affect hemopoietic cells from discussion of cytokines that exert effects on immune cells. Furthermore, secondary effects on immune cells via hemopoietic cells complicate the picture. Application of the principles of cytokine signaling to the clinical setting may necessitate new trial design structures that take into consideration donor and host characteristics as well as the kinetics of GVHD development.