Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Adoptive Transfer”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources

[Transarterial immuno-chemotherapy including adoptive transfer of autologous cultured lymphocytes for stage IV breast cancer patients with locally-advanced tumor].

Immuno-chemotherapy via a catheter in the subclavian artery using sequential treatment with OK-432, chemotherapeutic agents (ADM, 5-FU), and cultured autologous lymphocytes, was performed for 9 Stage IV breast cancer patients with locally-advanced primary tumor. Tumor reduction of more than 50% was observed in 8 patients including 4 whose breast tumors had disappeared. Among 11 evaluable distant metastatic lesions, 7 (1 pleural effusion, 2 lung, 2 liver, 2 bone metastases) regressed after local immunotherapy of breast or additional regional immunotherapy (1 lung, 1 liver, 1 pleural effusion). Median survival time to date is 56 months. Five patients are currently alive, although 3 of them did not undergo mastectomy. Local immuno-chemotherapy may be useful because (a) toxicity is limited, (b) low doses of anti-cancer agents during the therapy (median dose of ADM, 60 mg) do not limit subsequent systemic chemotherapy, and (c) distant metastases often regress concomitantly with the primary lesions.

Adult↗

A study of the safety and survival of the adoptive transfer of genetically marked syngeneic lymphocytes in HIV-infected identical twins.

This phase I/II pilot project will evaluate the survival, tolerance, safety, and efficacy of infusions of activated, gene marked, syngeneic T lymphocytes obtained from HIV seronegative identical twins on the functional immune status of HIV infected twin recipients. T cells from each seronegative twin will be obtained by periodic apheresis, separated into CD4 and CD8 enriched populations by monoclonal antibody affinity binding techniques, induced to polyclonal proliferation with anti-CD3 and rIL-2 stimulation, transduced with distinctive neoR retroviral vectors, and expanded 10-1,000 fold in numbers during approximately 2 weeks of culture. These marked T cell fractions will then be infused into the seropositive twins and the survival of the uniquely marked T cell populations will be monitored by vector-specific PCR, while the recipients' functional immune status is monitored by standard in vitro and in vivo testing protocols. A total of 3 cycles of treatment will be given at intervals of 6 weeks between infusions.

Adolescent↗

Adoptively transferred CD4+ lymphocytes from CD8 -/- mice are sufficient to mediate the rejection of MHC class II or class I disparate skin grafts.

Recent studies revealed that CD4+ cells initiate allograft rejection through direct recognition of allogeneic MHC class II Ags and indirect recognition of MHC peptides processed by self APCs. Both pathways were shown to help CD8+ cells that eventually lysed allogeneic MHC class I-presenting targets. There was little evidence, however, that CD4+ cells are sufficient for graft rejection. We studied skin graft rejection by CD8-deficient (CD8 -/-) mice. We showed that BALB/cJ(H-2d) CD8 -/- mice could reject allogeneic skin from C57BL/6J(H-2b) mice deficient in MHC class I or in MHC class II Ags. To understand the role of CD4+ cells in this process, we isolated them from CD8 -/- mice and transferred them to BALB/cJ nude mice that had been grafted with allogeneic skin (H-2b) from animals deficient in MHC class I or MHC class II. Nude mice injected with CD4+ cells rejected MHC class II and, albeit more slowly, MHC class I disparate skins. We showed in vitro evidence that CD4+ cells were not cytotoxic toward MHC class I or MHC class II disparate targets and that they recognized MHC class I allogeneic targets through indirect recognition. CD4+ cells produced Th1 cytokines, but not IL-4, following stimulation with allogeneic cells. Furthermore, intragraft TNF-alpha was elevated in skin grafted onto nude mice reconstituted with CD4+ cells compared with nonreconstituted mice. This suggests that MHC class II- or MHC class I-guided CD4+ cells alone are sufficient to induce rejection by the generation of cytokine-induced lesions.

Animals↗

Induction of permanent regression of Friend virus (FV) leukemia by adoptive transfer of T helper and not T cytotoxic cells.

Friend virus (FV) induces a progressive erythroleukemia that can be made to permanently regress by the transfer of in vitro cultured virus-specific T cells (CTL/RFB) without any other adjunctive treatment. To determine the role of T cells in regression, CTL/RFB were enriched for specific T-cell subsets by treatment with monoclonal anti-Lyt2.2 or anti-L3T4 antibody and complement (C'). Pre-treatment of CTL/RFB with anti-Lyt2 antibody and C' did not affect permanent regression incidence, while CTL/RFB depleted of L3T4+ cells induced temporary regressions with all mice recurring. The number of splenic Lyt2+ (CD8+ equivalent) cells was constant irrespective of the leukemic status of the animals. However, the number of L3T4+ cells (CD4+ equivalent) in leukemic mice was three-fold lower than that of normal mice with regressed mice demonstrating a 30% increase in the number of L3T4+ cells compared to normals. Spleen cells from leukemic animals were also unable to produce IL-2 in response to mitogen stimulation. These results indicate that L3T4+ cells are involved in regression of erythroleukemia.

Animals↗

Regulatory Th2 response induced following adoptive transfer of dendritic cells in prediabetic NOD mice.

We previously demonstrated that immunotherapy with dendritic cells (DC) prevented diabetes development in prediabetic NOD mice and that this effect was optimal when using a stimulatory DC population generated from bone marrow cells cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4. In this study, we have investigated the mechanism by which GM-CSF- and IL-4-cultured DC prevent diabetes in prediabetic NOD mice. Histological analysis of pancreatic tissue from DC-treated mice revealed a reduction in the severity of insulitis compared to controls. Analysisof the T cell response in DC-treated mice suggested a general shift towards a Th2-dominated response, as determined by cytokine production following either concanavalin A or anti-TCR stimulation. Furthermore, sorted CD45RB(lo) CD25+ CD4+ T cells from the spleen of DC-treated mice produced high amounts of Th2 cytokines following anti-TCR stimulation, suggesting that these cells are responsible for the apparent Th2 shift. We conclude that DC therapy may have corrected the immunoregulatory defect in the NOD mouse, thus restoring a balance between pathogenic Th1 cells and protective Th2 cells.

Animals↗

Adoptive transfer of human lymphoid cells to severely immunodeficient mice: models for normal human immune function, autoimmunity, lymphomagenesis, and AIDS.

Though the development of human-to-mouse xenotransplant models is in its infancy, astonishing progress has been made in a short period of time. Two experimental applications have been developed: short-term transfer of human lymphocytes to generate models for autoimmunity and infectious diseases, and long-term engraftment of tissues with self-renewal potential. Human PBL-SCID mice have been used by multiple laboratories to study normal and autoimmune antibody responses, and have been shown to be readily infectable with HIV-1. SCID mice grafted with fetal tissue have been developed for studies of HIV-1 infection and its therapy as well as for studies of human hematopoietic cell differentiation. Human tumors appear to grow better in SCID mice than in nude mice, and hu-PBL-SCID mice can develop EBV-related B cell lymphoproliferative disease that resembles the immunoblastic lymphomas appearing in immunosuppressed transplant recipients. There is some evidence of mouse NK cells responding to the human xenograft, and of human T and B cells responding to mouse xenoantigens in these models, but these responses are not generally strong enough to have a major impact on human immune function. The use of these surrogate human models is expected to have a major impact on the understanding and treatment of human disease.

Acquired Immunodeficiency Syndrome↗

Migration of activated lymphocytes when adoptively transferred into cannulated rat brain.

Migration of fluorescent DNA-labeled or 111Indium-labeled activated lymphocytes was studied in normal rat brain bearing surgically implanted cannulas. The migration of allogeneic cytotoxic T lymphocytes (CTL), derived from the DA rat (DA anti Fischer CTL), and of syngeneic concanavalin A (ConA)-activated lymphocytes (Fischer Con A blasts), was determined in Fischer rats between 2 h and 7 days post instillation into parietal brain. Whole body nuclear imaging indicated that the majority of the radiolabeled lymphocytes, either syngeneic or allogeneic, were present in the brain at 2 and 18 h. Autoradiography of brain slices demonstrated that label was located throughout the brain and in both hemispheres at all time points. By direct tissue radioassay, approximately 60% of the injected dose was present between 2 and 18 h; this decreased to 18% by day 7. By fluorescence microscopy, large numbers of lymphocytes were visible up to 3-4 days. The lymphocytes traveled from the instillation site into both cerebral hemispheres primarily following white matter tracts. Preferential localization of fluorescently labeled lymphocytes was seen in the corpus callosum, internal and external capsules, anterior commissures, lateral olfactory tracts, white matter connections in the caudate and putamen, mammillothalamic and optic tracts. Overall, gray matter contained fewer cells although perivascular spaces within it had high concentrations of cells, indicating these spaces may act as points of egress.

Animals↗

Adoptive transfer of anti-cytomegalovirus effect of interleukin-2-activated bone marrow: potential application in transplantation.

This work is a continuation of our studies that showed that interleukin-2 (IL-2)-activated murine bone marrow (ABM) cells have potent cytotoxic potential against murine cytomegalovirus (MCMV)-infected targets in vitro, without loss of reconstitutive ability in vivo. Our data show that ABM cells lyse the MCMV-infected cells in vitro, at both acute and chronic stages of infection; this lysis is specific for the MCMV-infected cells. ABM cells supplemented with IL-2 therapy virtually eradicated the viral infection and prolonged the survival of MCMV-infected Balb/c mice, whether or not they were immunocompromised by irradiation (P less than .001 in both situations). Efficacy of ABM cells alone or IL-2 alone was less than the combination of ABM cells and IL-2. The efficacy of combination treatment with ABM cells and IL-2 in improving the survival of MCMV-infected mice was comparable, whether used in a preventive or a therapeutic setting. Therapy with ABM plus IL-2 also prevented the reactivation of chronic MCMV infection after irradiation. Preliminary findings indicate that Thy-1+ and asialo GM1+ cells limited the MCMV proliferation by approximately 30% and 80%, respectively, while BM macrophages limited the proliferation of MCMV by 100%. These results suggest that BM transplantation (BMT) with ABM cells followed by IL-2 therapy may constitute a novel strategy to improve the host resistance against cytomegalovirus infection after BMT.

Animals↗

Vaccine-stimulated, adoptively transferred CD8+ T cells traffic indiscriminately and ubiquitously while mediating specific tumor destruction.

It has been suggested that antitumor T cells specifically traffic to the tumor site, where they effect tumor destruction. To test whether tumor-reactive CD8(+) T cells specifically home to tumor, we assessed the trafficking of gp100-specific pmel-1 cells to large, vascularized tumors that express or do not express the target Ag. Activation of tumor-specific CD8(+) pmel-1 T cells with IL-2 and vaccination with an altered peptide ligand caused regression of gp100-positive tumors (B16), but not gp100-negative tumors (methylcholanthrene 205), implanted on opposing flanks of the same mouse. Surprisingly, we found approximately equal and very large numbers of pmel-1 T cells (>25% of all lymphocytes) infiltrating both Ag-positive and Ag-negative tumors. We also found evidence of massive infiltration and proliferation of activated antitumor pmel-1 cells in a variety of peripheral tissues, including lymph nodes, liver, spleen, and lungs, but not peripheral blood. Most importantly, evidence for T cell function, as measured by production of IFN-gamma, release of perforin, and activation of caspase-3 in target cells, was confined to Ag-expressing tumor. We thus conclude that CD8(+) T cell-mediated destruction of tumor is the result of specific T cell triggering at the tumor site. The ability to induce ubiquitous homing and specific tumor destruction may be important in the case of noninflammatory metastatic tumor foci.

Animals↗

Tumour-induced polarization of tumour vaccine-draining lymph node T cells to a type 1 cytokine profile predicts inherent strong immunogenicity of the tumour and correlates with therapeutic efficacy in adoptive transfer studies.

Previously we have shown that vaccination with the poorly immunogenic B16BL6-D5 melanoma (D5) elicits a dominant type 2 (T2) cytokine response that fails to protect the host from a subsequent tumour challenge. Here we investigated whether the inherent immunogenicity of a tumour can be correlated with its ability to bias the anti-tumour cytokine response towards either a type 1 (T1) or a T2 profile. The immune response to six tumours of different inherent immunogenicity was assayed. By isolating l-selectinlow T cells from tumour vaccine draining lymph nodes (TVDLN), it was possible to detect tumour-specific cytokine responses from both immunogenic, poorly immunogenic and non-immunogenic tumours. Immunogenic tumours (MCA-304, MCA-309, MPR-4) induced a predominant tumour-specific T1 cytokine response. In contrast, weakly (MCA-310, MPR-3) and poorly/non-immunogenic tumours (MPR-5, D5) sensitized T cells with a predominant tumour-specific T2 cytokine response. A significant correlation (P < 0.025) between immunogenicity and the ratio of tumour-specific interferon-gamma : interleukin-4 (IL-4) secretion by TVDLN T cells was identified. We then documented that non-therapeutic T cells primed by the poorly immunogenic D5, recognized "tumour-rejection" antigens and that reprogramming their cytokine response, by in vitro culture with IL-12 and anti-IL-4, to a T1 profile uncovered therapeutic efficacy. In contrast, TVDLN T cells primed by a therapeutic vaccine lose therapeutic efficacy when cultured with IL-4. These results provide insights into the development of a protective anti-tumour immune response and strengthen the hypothesis that a T1 cytokine response is critical for T-cell-mediated tumour regression.

Animals↗

Adoptive transfer of allogeneic cytotoxic T lymphocytes equipped with a HLA-A2 restricted MART-1 T-cell receptor: a phase I trial in metastatic melanoma.

PURPOSE: We did a phase I dose-escalation trial to evaluate the feasibility and safety of intratumoral injections of C Cure 709, an allogeneic, continuous CTL cell line that, restricted by HLA-A2, recognizes MART-1-positive tumor cells through transduction with a T-cell receptor encoding gene. EXPERIMENTAL DESIGN: Cells were administered intratumorally in four dose levels ranging from 10(8) to 10(9) cells/d on days 1, 4, 7, 10, 14, and 28 of each treatment cycle to patients with metastatic melanoma. Main inclusion criteria were HLA-A2 tissue type, MART-1-positive tumor cells, and metastases suitable for ultrasound-guided injections. Patients were assessed for toxicity and response. Three to six patients were treated per dose level. Patients without progressive disease were offered up to three treatment cycles. RESULTS: Fifteen patients received a total of 24 treatment cycles with a total of 266 injections of C Cure 709. Toxicity was minor to moderate and most common injection site reactions were fever, fatigue, nausea/vomiting, and arthralgia/myalgia. Side effects disappeared in general within 24 hours. Toxicity was not dose dependent. One patient obtained a partial response, encompassing both metastases used and not used for intratumoral injections. Remaining patients did not achieve an overall response. In addition, we observed local regression of metastases used for injection in two patients and of metastases not used for injection in one patient. CONCLUSION: Intratumoral injections of C Cure 709 are feasible, safe, and capable of inducing tumor regression. Further investigation in a phase II setting is warranted.

Adult↗

A phase 1 study of adoptive transfer of autologous CD8+ T lymphocytes in patients with acquired immunodeficiency syndrome (AIDS)-related complex or AIDS.

Based on preclinical studies showing that CD8+ T lymphocytes of human immunodeficiency syndrome (HIV)-infected subjects have anti-HIV activities, a phase 1 study was undertaken to determine the safety and feasibility of infusing in vitro purified, activated, and expanded CD8+ cells as a therapeutic measure in seven patients with acquired immunodeficiency syndrome (AIDS)-related complex (ARC) or AIDS. Autologous CD8+ cells were first selectively isolated in monoclonal antibody-coated flasks from peripheral blood mononuclear cells recovered by leukapheresis. They were then cultured and expanded with phytohemagglutinin and recombinant interleukin-2 (rIL-2) before infusion. Five cycles of isolations and infusions of increasing numbers of CD8+ T cells were achieved in five of seven subjects. Five cycles could not be completed in two subjects with AIDS whose CD4+ cell counts were < or = 48/microliters. Infusions of CD8+ cells alone were well tolerated. Four patients received rIL-2 by continuous infusion for 5 days with their final cycle of CD8+ cells. All developed reversible adverse effects attributable to rIL-2. After infusion, 111In-labeled CD8+ cells quickly accumulated in the lungs, with less than 10% of the labeled cells remaining in the circulation. After 24 hours, labeled CD8+ cells were reduced in the lungs, but increased and persisted in liver, spleen, and bone marrow. Four of five patients who were treated with multiple infusions of CD8+ cells have improved or remained clinically stable, and the fifth developed Pneumocystis carinii pneumonia but recovered. This study demonstrated that infusion of autologous, in vitro expanded and activated CD8+ cells was feasible and clinically well tolerated in five of seven subjects with advanced HIV infections.

AIDS-Related Complex↗

Randomized trial of adoptive transfer of melanoma tumor-infiltrating lymphocytes as adjuvant therapy for stage III melanoma.

The aim of this study was to demonstrate the interest of using tumor-infiltrating lymphocytes (TIL) as adjuvant therapy for stage III (regional lymph nodes) melanoma. After lymph node excision, patients without any detectable metastases were randomly assigned to receive either TIL plus interleukin-2 (IL-2) for 2 months, or IL-2 only. The primary endpoint was determination of the duration of the relapse-free interval. Eighty-eight patients determined as eligible for treatment were enrolled in the study. After a median follow-up of 46.9 months, for the study population the analysis did not show a significant extension of the relapse-free interval or overall survival. However, a significant interaction ( P<0.001) was found between the treatment and the number of invaded lymph nodes. In the group with only one invaded lymph node, the estimated relapse rate was significantly lower ( P(adjusted)=0.0285) and the overall survival was increased ( P(adjusted)=0.039) in the TIL+IL-2 arm compared with the IL-2 only arm. No differences between the two arms, either as regards the duration of disease-free survival or overall survival, were noted in the group with more than one invaded lymph node whatever the number of invaded lymph nodes. Treatment was compatible with normal daily activity. This study demonstrates for the first time that the efficiency of TIL in stage III melanoma (AJCC) is directly related to the number of invaded lymph nodes, indicating that tumor burden might be a crucial factor in the efficacy and/or in vitro expansion of T cells specific for autologous tumor antigen, a finding which could be of value in future vaccine development for the treatment of melanoma.

Adjuvants, Immunologic↗

Immune modulation in cancer patients after adoptive transfer of anti-CD3/anti-CD28-costimulated T cells-phase I clinical trial.

Anti-CD3/anti-CD28 monoclonal antibody-coactivated T cells (COACTs) proliferate, secrete tumoricidal cytokines, and mediate non-major histocompatibility complex (MHC)-restricted cytotoxicity. This phase I study was done to determine the safety, maximum tolerated dose, technical limits of expansion, and modulation of immune functions in cancer patients given COACTs. Coactivated T cells were produced by stimulating peripheral blood mononuclear cells (PBMCs) with OKT3 anti-CD3 and 9.3 (anti-CD28)-coated beads in the presence of 100 IU interleukin (IL)-2 per milliliter for 14 days. The beads were removed after 4 days of culture. Ten courses of COACTs were given to eight patients with renal cell (1), ovarian (2), breast (1), and colorectal (4) carcinomas; two patients received two courses of COACTs. Patients were given up to 10 x 10 9 COACTs twice a week for 3 weeks without dose-limiting toxicities. Patients at the first and second dose levels received a mean total of 17.6 and 42.4 x 10 9 COACTs, respectively. After 14 days of culture, the COACTs contained a mean of 57.5% CD4+ cells and 42.5% CD8+ cells, exhibited non-MHC-restricted cytotoxicity, and produced significant amounts of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and granulocyte macrophage colony-stimulating factor (GM-CSF). Infusions were safe and induced measurable serum levels of IFNgamma, TNFalpha, and IL-4 in two patients. Peripheral blood mononuclear cells from patients who received COACTs secreted higher amounts of IFNgamma and GM-CSF on in vitro anti-CD3/anti-CD28 restimulation than PBMCs obtained before immunotherapy. The detection of cytokines in patient sera and enhanced in vitro production of cytokines by anti-CD3/anti-CD28-stimulated patient PBMCs after COACT infusions suggest that COACTs were modulating immune responses in cancer patients.

Adult↗

Development and therapeutic effect of adoptively transferred T cells primed by tumor lysate-pulsed autologous dendritic cells in a patient with metastatic endometrial cancer.

We describe a 65-year-old woman with a large surgically unresectable and chemoresistant liver metastasis of endometrial carcinoma who was treated by infusion with peripheral blood T cells stimulated with tumor lysate-pulsed autologous dendritic cells (DC). Extensive in vitro characterization of the DC-activated T cells included phenotypic analysis, cytotoxicity, and intracellular cytokine secretion. High cytotoxicity was observed against autologous tumor cells, but not against NK-sensitive K562 cells, autologous Con-A lymphoblasts, or autologous Epstein-Barr virus-transformed lymphoblastoid cells. Blocking studies demonstrated that lytic activity was HLA class I restricted. Two-color flow cytometric analysis revealed that a significant proportion of CD8+ T cells was also CD56+, and analysis of intracellular IFN-gamma and IL-4 expression suggested a type 1 cytokine bias. The patient was treated by three infusions of tumor-specific T cells at 3- to 4-week intervals, and in vivo distribution of the T cells was followed by (111)In oxine labeling and serial gamma camera imaging. Tumor localization and accumulation of labeled lymphocytes was consistently detected at serial time points following each injection. However, deep infiltration of the large tumor mass by activated T cells was minimal, as evaluated in 3 dimensions by single photon emission computerized tomography (SPECT) imaging. Transient serum increases of the tumor marker lactate dehydrogenase (LDH), were detectable after each injection. Similar posttreatment elevations were seen for serum uric acid and potassium. Clinically, stabilization of the large liver metastasis was obtained during treatment. Collectively, these results indicate that tumor-specific CD8+ cytotoxic T-cell responses can be generated in patients with endometrial cancer, and suggest that T-cell immunotherapy may be of therapeutic value in patients harboring metastatic disease.

Aged↗

Adoptive transfer of immunity: a new strategy to interfere with severe hepatitis virus reinfection after woodchuck liver transplantation.

BACKGROUND: The effective transfer of humoral immunity to hepatitis B virus was first demonstrated after clinical and experimental bone marrow transplantation. This strategy is now evaluated in the woodchuck transplantation model, in which protection from reinfection can be tested. METHODS: Animals negative for woodchuck hepatitis virus (WHV) (n = 3) were vaccinated using plasmids expressing woodchuck hepatitis virus surface (WHs), woodchuck hepatitis virus core (WHc), and woodchuck interferon-gamma in combination with a protein vaccine (WHs antigen [Ag]) three times before liver donation. Control animals (n= 4) received the liver from non-immunized donors. Chronic WHV carriers served as recipients. The viral load in serum and liver tissue was monitored pretransplant and posttransplant for up to 11 weeks by dot blot, Northern blot, Southern blot, and immunohistochemistry for WHc and WhsAg. RESULTS: Donor vaccination was effective, as indicated by the development of anti-WHc and anti-WHs antibodies. Transplanting the livers of these donors resulted in a reduction of viral load in two of three animals. No viral DNA was detected in repeated serum samples by dot-blot hybridization technique. However, polymerase chain reaction for viral DNA extracted from serum was always positive. WHV replication intermediates and WHV RNA were absent in repeated liver biopsies. Only few hepatocytes stained weakly positive for WHc protein and frequency, and the intensity of WHsAg positive hepatocytes was low. The third animal developed severe reinfection within 3 weeks, similar to the woodchucks in the control group. CONCLUSIONS: Liver transplantation from immunized donors to chronic carriers seems to be a promising strategy to reduce and delay severe reinfection, which may be applicable in clinical liver transplantation.

Animals↗

Adoptive transfer of the hematopoietic system of trisomic mice with limited life span: stem cells from six different trisomies are capable of survival.

The life span of murine trisomies is limited to the fetal or early postnatal period. However, rescue of the hematopoietic system of fetal mice with trisomies (Ts) 12, 13, 14, 16, 18, and 19 is possible by transplanting hematopoietic stem cells from the liver into lethally irradiated adult hosts. Thus, radiation chimeras with permanent and almost complete trisomic hematopoietic and lymphocytopoietic systems were constructed. The longest documented survival of a trisomic graft was 12 months in Ts 19 chimeras. Blood counts in trisomic chimeras reveal a marked anemia in Ts 16 chimeras; lymphocytopenia in Ts 12, Ts 16, and Ts 19 chimeras; and granulocytopenia in Ts 18 chimeras. Survival rates of Ts 12, Ts 18, and Ts 19 chimeras were not different from those of the respective controls, whereas survival rates of chimeras with Ts 13 and Ts 16 hematopoiesis were markedly reduced and that of Ts 14 chimeras only slightly reduced. These results indicate that transplanted hematopoietic stem cells from Ts 13, Ts 14, and Ts 16 fetuses exhibit relevant genetically determined defects, resulting in a reduced restoration capacity of hematopoietic organs and/or deficiencies of differentiated blood cells.

Animals↗