A comparative study on the efficacy of CD8-positive cells in enhancing allogeneic bone marrow engraftment: cell sorting vs microbead selection

We have used a superparamagnetic microbead selection system to positively select a murine bone marrow CD8+ cell population. The functional ability of these cells to enhance allogeneic bone marrow engraftment was compared with that of fluorescence activated cell sorter purified CD8+ cells. The CD8+ cell population prepared by the microbead selection procedure was as effective as cell sorter purified CD8+ cells in enhancing T cell-depleted allogeneic bone marrow engraftment in lethally irradiated mice. Phenotypic characterization of these cells shows that most of these CD8+ cells express CD3 and the T cell antigen receptor complex.

Digestion of timothy silage and hay in reindeer

Leafy timothy (Phleum pratense) silage (S), silage mixed with molasses (SM) and hay (H) were fed to nine male reindeer (Rangifer tarandus tarandus) calves in winter to investigate rumen function and digestion. Three calves were given S with 18.5% dry matter (DM), three were given SM (21.9% DM) and three were given H (85.0% DM). The content of water soluble carbohydrates (in % of DM) was 8.2% in S, 16.0% in SM and 8.5% in H. Median (range) daily DM food intake per kg BM was 12.9 (9-2-14.4) g in calves fed S, 19.0 (19-0-21.9) g in calves fed SM and 21.0 (19.2¬21.1) g in calves fed H. In vivo digestion of S and SM DM ranged from 78.5-83.1% compared to only 69-9-72.9% in calves fed H. In vitro DM digestion (IVDMD) of cellulose (median) incubated for 48 hours in rumen fluid was, however, significantly (F = 0.05) lower in calves fed S (24.4%) compared to calves fed SM (42.2%). Median IVDMD of cellulose (48 hours) in calves fed H was 36.4%. Total concentration of VFA (range) in the rumen fluid from reindeer fed H (99.7-113.6 mM) and was significantly (P<0.05) higher compared to animals fed S (57.7-85.9 mM) or SM (51.4-72.0 mM). Likewise, the pH of the rumen fluid (range) was significantly (P<0.05) lower in reindeer fed H (6.40-6.78) compared to animals fed S (6.97-7.30) or SM (6.79-7.27). Based on this study it is concluded that leafy timothy preserved as hay seems to be more suitable as emergency feed compared to silage. Supplementation of molasses to silage seems to stimulate food intake and ruminal cellulose digestion in reindeer. The lower intake of S compared to SM or H by reindeer may be explained by ruminal energy deficiency.

Clinical application of retroviral gene transfer in oncology: results of a French study with tumor-infiltrating lymphocytes transduced with the gene of resistance to neomycin

PURPOSE

Adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL) and interleukin-2 (IL-2) has been reported to mediate tumor regression in some human cancers. To define better the biologic characteristics of TIL, especially survival and distribution in vivo, we performed a gene-marker study in patients with advanced malignancies.

PATIENTS AND METHODS

We treated five patients with metastatic melanoma or renal cell carcinoma with adoptive immunotherapy. TIL were genetically modified, before their infusion, using a recombinant retroviral vector that contained the marker gene coding for resistance to neomycin (NeoR).

RESULTS

All of the patients tolerated the treatment well and none of the theoretic safety hazards due to the retroviral gene transduction was observed. The presence of the NeoR gene in TIL was detected by Southern blot analysis, with an efficiency of transduction that ranged from 1% to 26%. With polymerase chain reaction (PCR) analysis, we demonstrated that gene-modified TIL can survive for several months after reinjection, since positive blood samples were observed up to day 260 following reinjection. Eight malignant biopsy specimens were obtained from three patients after cell infusion. TIL were detected in only four of these eight tumor deposits on days 7 and 260.

CONCLUSION

These results confirm the feasibility and safety of using in vitro retroviral gene transduction in human lymphocytes to analyze their in vivo distribution for further therapeutic applications. However, a selective and prolonged retention of TIL at the tumor site was not found in this study.

Simultaneous use of two retroviral vectors in human gene marking trials: feasibility and potential applications

Two Moloney murine leukemia virus (Mo-MLV)-based neoR retroviral vectors--LNL6 and G1Na--were used to transduce various human tumor-infiltrating lymphocytes (TIL) populations. These groups included bulk CD(8+)- and CD(4+)-enriched TIL from human renal cell carcinomas and melanomas. Transduction efficiencies averaged 5% for single 4-hr supernatant infections. Integrated provirus could be detected for up to 4 weeks of in vitro culture. LNL6 provirus could be distinguished from G1Na provirus using specific polymerase chain reaction (PCR) primers. A single neomycin phosphotransferase (neoR) gene copy could be detected in 10(5) TIL. Using quantitative PCR, the relative ratio of LNL6 to G1Na copies in the same sample could be determined even at low copy numbers. These preclinical studies demonstrate the feasibility of using two retroviral marking vectors in human gene therapy efforts.

Helper virus induced T cell lymphoma in nonhuman primates after retroviral mediated gene transfer

Moloney Murine Leukemia Virus (MoMuLV) causes T cell neoplasms in rodents but is not known to be a pathogen in primates. The core protein and enzyme genes of the MoMuLV genome together with an amphotropic envelope gene are utilized to engineer the cell lines that generate retroviral vectors for use in current human gene therapy applications. We developed a producer clone that generates a very high concentration of retroviral vector particles to optimize conditions for gene insertion into pluripotent hematopoietic stem cells. This producer cell line also generates a much lower concentration of replication-competent virus that arose through recombination. Stem cells from rhesus monkeys were purified by immunoselection with an anti-CD34 antibody, incubated in vitro for 80-86 h in the presence of retroviral vector particles with accompanying replication-competent virus and used to reconstitute recipients whose bone marrow had been ablated by total body irradiation. The retroviral vector genome was detected in circulating cells of five of eight transplant recipients of CD34+ cells and in the circulating cells of two recipients of infected, unfractionated bone marrow mononuclear cells. Three recipients of CD34+ cells had a productive infection with replication-competent virus. Six or seven mo after transplantation, each of these animals developed a rapidly progressive T cell neoplasm involving the thymus, lymph nodes, liver, spleen, and bone marrow. Lymphoma cells contained 10-50 copies of the replication-competent virus, but lacked the retroviral vector genome. We conclude that replication-competent viruses arising from producer cells making retroviral vectors can be pathogenic in primates, which underscores the importance of carefully screening retroviral producer clones used in human trials to exclude contamination with replication-competent virus.

Use of cell-free retroviral vector preparations for transduction of cells from the marrow of chronic phase and blast crisis chronic myelogenous leukemia patients and from normal individuals

Marrow cells were exposed to the LNL6 or G1N safety-modified variants of the N2 retrovirus, which contain the G418 bacterial resistance gene neo. The frequency of acquisition of the G418 resistance phenotype following exposure to LNL6 or G1N was compared among hematopoietic progenitor cells from the marrow of patients with chronic phase chronic myelogenous leukemia (CML), blast crisis CML, or from nonleukemic individuals. Under the conditions of our experiments, the myeloid committed progenitor cells from 3 of 6 nonleukemic individuals, 9 of 18 chronic-phase CML patients, and 2 of 4 blast crisis CML patients acquired resistance to at least 1 mg/ml G418 following incubation with cell-free supernatants from the PA317 LNL6 or PA317 G1N producer cell lines. Ten of the 32 colonies growing up in 0.8 mg/ml G418 from chronic-phase marrow exposed to LNL6 were shown to contain the neo gene by polymerase chain reaction (PCR) assay of DNA. These results were consistent with estimates of the transduction frequency based on acquisition of resistance to G418 as the number of colonies growing under G418 selection was always greater at 0.8 mg/ml G418 than at higher concentrations of G418 (1.0-1.4 mg/ml). The average transduction frequency at each G418 concentration (1.0, 1.2, and 1.4 mg/ml) in cells from blast crisis CML cells ranged from 2 to 14%, as measured by acquisition of G418 resistance. Chronic-phase CML showed slightly lower average frequencies of transduction (0.6-2.8% of the colonies are G418 resistant). The average transduction frequency of cells from nonleukemic marrow was as high as that seen from the marrow of chronic-phase CML individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular analysis of retroviral transduction in chronic myelogenous leukemia

We have developed a polymerase chain reaction (PCR) assay for detection of integrated retroviral transgenomes containing the neo G418 resistance gene in colonies (40 cells or more) grown in G418 selection after exposure to the neo-positive retrovirus LNL6. This assay also provides for simultaneous characterization of these colonies as belonging to a chronic myelogenous leukemic (bcr-abl positive) or nonleukemic population (bcr-abl negative). Using these techniques, we assessed transduction of the LNL6 retrovirus into the normal and leukemic cells of a blast-crisis chronic myelogenous leukemia (CML) patient. This work was designed to support the use of the LNL6 retroviral marker to help identify the origin of relapse after autologous marrow infusion. The data from these experiments show that the majority of CML blast crisis cells that, following exposure to the LNL6 virus, produce colonies under rigorous G418 selection are indeed transduced by the virus, as shown by the presence of the neo retroviral gene. Most of these colonies are also shown to be leukemic by PCR detection of the bcr-abl RNA. This demonstrates the feasibility of the study of CML marrow for retroviral marking. These procedures will be of use in establishing if relapse arises from leukemic blasts which contaminate purged autologous bone marrow infused following intensive therapy for leukemia.

Gene transfer into humans--immunotherapy of patients with advanced melanoma, using tumor-infiltrating lymphocytes modified by retroviral gene transduction

BACKGROUND AND METHODS

Treatment with tumor-infiltrating lymphocytes (TIL) plus interleukin-2 can mediate the regression of metastatic melanoma in approximately half of patients. To optimize this treatment approach and define the in vivo distribution and survival of TIL, we used retroviral-mediated gene transduction to introduce the gene coding for resistance to neomycin into human TIL before their infusion into patients--thus using the new gene as a marker for the infused cells.

RESULTS

Five patients received the gene-modified TIL. All the patients tolerated the treatment well, and no side effects due to the gene transduction were noted. The presence and expression of the neomycin-resistance gene were demonstrated in TIL from all the patients with Southern blot analysis and enzymatic assay for the neomycin phosphotransferase coded by the bacterial gene. Cells from four of the five patients grew successfully in high concentrations of G418, a neomycin analogue otherwise toxic to eukaryotic cells. With polymerase-chain-reaction analysis, gene-modified cells were consistently found in the circulation of all five patients for three weeks and for as long as two months in two patients. Cells were recovered from tumor deposits as much as 64 days after cell administration. The procedure was safe according to all criteria, including the absence of infections virus in TIL and in the patients.

CONCLUSIONS

These studies demonstrate the feasibility and safety of using retroviral gene transduction for human gene therapy and have implications for the design of TIL with improved antitumor potency, as well as for the possible use of lymphocytes for the gene therapy of other diseases.

Thymus and B cell reconstitution in severe combined immunodeficiency after transplantation of monoclonal antibody depleted parental mismatched bone marrow

Two brothers were transplanted with bone marrow which was depleted of mature T cells with monoclonal antibody CT-2 plus complement. One child died of sepsis due to candida present prior to transplant. The other is alive and well with full T and B cell reconstitution over 36 months after transplant. Thymus biopsy taken after transplant demonstrated normal morphology and cellularity. Portions of the marrow that were radiolabeled permitted an assessment of traffic patterns of aliquots that were injected intravenously and directly into the marrow space. The studies reported here document that a one haplotype mismatch is not a sufficient disparity to preclude both B and T cell reconstitution, and that monoclonal antibody plus complement is an effective method for T cell depletion.

Alcohol-related disease in hospital patients

Ninety medical records of patients with an alcohol-related diagnosis who were admitted to a major city teaching hospital over a 12-month period were reviewed to assess the ways in which the problem had been recognized and managed by hospital staff members. The overall frequency of an alcohol-related diagnosis of 1.8% suggested an under-reporting of this medical problem. Those patients who were identified were, in general, well managed, but patients with less obvious and permanent clinical problems, such as non-dependent abuse of alcohol or acute alcoholic intoxication, were more likely to have minimal or no attention directed to the drinking problem. Our review suggests that medically trained staff members identify significant organ damage readily. It also suggested that more attention needs to be directed to the education of medical students and staff members in the recognition of the early stages of alcohol dependency and misuse, so that its more serious complications might be minimized by effective intervention.

Clinical trial depleting T lymphocytes from donor marrow for matched and mismatched allogeneic bone marrow transplants

Nine patients received T-lymphocyte-depleted histocompatible bone marrow and 28 patients received T-lymphocyte-depleted histoincompatible bone marrow. Eight of nine patients receiving matched bone marrow quickly engrafted without severe graft-versus-host disease (GvHD). None of the eight patients received anti-GvHD prophylaxis medications. Two of these eight patients are currently alive. Nonengraftment and severe GvHD were problems seen in some of the patients given the histoincompatible bone marrow. Additional cytarabine pretransplant permitted engraftment in those patients undergoing histoincompatible transplants for treatment of malignancy, and prednisone and cyclosporine posttransplant reduced the incidence of acute GvHD in those given T-lymphocyte-depleted grafts. Seven of these 28 patients are currently alive. T-lymphocyte-depleted marrow can reduce the occurrence or prevent severe acute GvHD, especially when combined with additional prednisone and cyclosporine; however, the impact on relapse patterns and survival remains to be determined. The occurrence of nonengraftment and treatment-related lymphomas are formidable problems to overcome.