Search PubMed⌕ Search

Biomedical subjects

S Slavin

Publications and source records attributed to S Slavin.

At least 253 records · Page 14Linked to original sources
PubMed1992

The role of recombinant cytokines and other immunomodulators on engraftment following allogeneic bone marrow transplantation in mice.

BALB/c mice were conditioned by total body irradiation (TBI) with a suboptimal (475 cGy) or optimal (600 cGy) radiation dose for induction of chimerism subsequent to administration of 10(7) (BALB/c x C57BL/6) F1 (F1) bone marrow cells in order to test whether a variety of recombinant cytokines and other immunomodulators caused positive or negative effects on engraftment at different time intervals post-bone marrow transplantation (BMT). Engraftment in recipient mice conditioned by the minimal dose of TBI permitting 100% induction of chimerism (600 cGy) was not impaired following treatment with recombinant human interleukin 2 (IL2) (10(4) Cetus Units x 3/day i.p.), alpha interferon (alpha IFN) (10(4) units/day i.p.), gamma interferon (gamma IFN) (10(4) U/day i.p.) and combinations of IL2 + alpha IFN as well as IL2 + gamma IFN given either 5 days prior to or 5 days following BMT. Likewise, neither PGE2 (50 micrograms x 2/day i.p.) nor indomethacin (25 micrograms x 2/day i.p.) given either immediately prior to or immediately following BMT for 3 consecutive days had any detectable effect on chimerism. To investigate the putative beneficial effects of IL2 in enhancing marrow engraftment, BALB/c mice were irradiated with a suboptimal dose of TBI (475 cGy) followed by reconstitution with 10(7) F1 marrow cells supplemented with 2 x 10(6) F1 spleen cells. IL2 (10(4) U x 3/day i.p. x 5 days) was administered either prior to TBI, between TBI and BMT, immediately following BMT, or starting 2 weeks post-BMT.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Use of recombinant human interleukin-2 in conjunction with syngeneic bone marrow transplantation in mice as a model for control of minimal residual disease in malignant hematologic disorders.

Unlike allogeneic bone marrow transplantation (BMT), autologous BMT is not accompanied by immune-mediated graft-versus-leukemia (GVL) effects; hence, the relapse rate observed after autologous BMT in malignant hematologic disorders is higher than that observed after allogeneic BMT. Autologous BMT represents a much safer medical procedure available for many patients in need in situations where allogeneic BMT is not feasible or risky. The present experiments were designed to investigate whether it might be possible to combine the therapeutic benefits of autologous BMT with additional immunotherapy after BMT. The tumor model used for investigating GVL effects was the murine B-cell leukemia (BCL1), a spontaneous, nonimmunogenic, highly lethal leukemia of BALB/c origin. BALB/c mice inoculated with 10(3) BCL1 leukemia cells were treated on day-1 with cyclophosphamide 100 mg/kg and transplanted with normal syngeneic BM cells on day 0. High-dose recombinant interleukin-2 (rIL-2) (100,000 Cetus units x 3/day intraperitoneally x 5 consecutive days) was initiated on day +1, +7, or +21 after BMT. Kinetics of lymphocyte reconstitution after syngeneic BMT indicated a steep increase in the absolute number of peripheral blood lymphocytes on days 17 through 24. All experimental groups were observed for relapse. Mice receiving no rIL-2 therapy relapsed and died within 50 days after BMT, whereas mice receiving rIL-2 showed long-term disease-free survival. Optimal time for administration of rIL-2 was noted at 3 weeks post-BMT, with 90% of the mice surviving with no evidence of disease for more than 1 year. Similarly, when 10(4) BCL1 cells were given 1 day after syngeneic BMT to simulate minimal residual disease after syngeneic BMT, rIL-2 therapy administered at 14 days post-BMT seemed effective in prolonging disease-free survival in contrast to the same regimen given at 1 day after BMT. Our data suggest that immunotherapy with rIL-2 should be further investigated as a new immunotherapeutic tool for decreasing the relapse rate after BMT for hematologic malignancies.

Animals↗
PubMed1991

Treatment of pure red-cell aplasia following major ABO-mismatched T-cell-depleted bone marrow transplantation. Two case reports with successful response to plasmapheresis.

Major ABO-mismatched bone marrow transplantation (BMT) may be accompanied by red-cell haemolysis, but pure red-cell aplasia following BMT is a rare complication. Two cases of transient pure red-cell aplasia following T-lymphocyte-depleted BMT for a period of greater than 20 weeks are described, both of which responded to one cycle of plasmapheresis. The prompt response of the two patients described with red-cell aplasia with no evidence of haemolysis suggests that plasmapheresis may be considered in such clinical situations as a first treatment of choice before attempting more complex modes of therapy.

ABO Blood-Group System↗
PubMed1991

Effects of recombinant human granulocyte and granulocyte-macrophage colony-stimulating factors on neutrophil function following autologous bone marrow transplantation.

Functional activity of peripheral blood neutrophils was assessed in eight patients at 4, 6, 8, 10 and 12 weeks following autologous bone marrow transplantation (ABMT). Functions studied included superoxide generation (O2-) intracellular killing of Staphylococcus aureus, phagocytosis and killing of Candida albicans. Neutrophils were tested following in vitro preincubation with 300 pM granulocyte-macrophage colony-stimulating factor (GM-CSF), 1.2 nM granulocyte colony-stimulating factor (G-CSF) or buffered solution (diluent) as control. Our data indicate that during the early period (weeks 4-6) following ABMT most of the patients exhibited diminished neutrophil oxidative metabolism, defective phagocytosis and killing of C. albicans and reduced capacity to kill S. aureus. In some patients a gradual increase in the functional activity of neutrophils occurred with time. Both GM-CSF and G-CSF induced in vitro amplification of (a) O2- production in response to fmet-leu-phe (FMLP) (b) phagocytosis and killing of C. albicans and (c) killing of S. aureus. This study suggests that GM-CSF and G-CSF may enhance the depressed functional activity of neutrophils following ABMT.

Adolescent↗
PubMed1991

Control of relapse due to minimal residual disease (MRD) by cell-mediated cytokine-activated immunotherapy in conjunction with bone marrow transplantation.

In conclusion, lessons from the animal model of lymphoid leukaemia suggest that in the setting of allogeneic BMT, under certain conditions GVL effects may be separable from GVHD; more specifically, GVL effects may be induced despite development of tolerance of donor cells against allogeneic host alloantigens. The latter phenomenon suggests that either curative GVL effects may be inducible despite subclinical GVHD or alternatively that effector cells of GVL may recognize different tumour-associated targets different from cell surface determinants of 'normal' alloantigens. Alternatively, effector cells of GVL may be distinguished from effector cells of GVHD. It is tempting to suggest that NK and IL2-aspirated NK cells may play a major role as effector cells of GVL in an MHC non-restricted fashion, different from classical CD8+ cytotoxic cells that certainly play a major role in GVHD and GVL. Once proven, the latter hypothesis may help develop new and safer therapeutic approaches since NK cells and products of the NK cell family are unlikely to play a major role, if any, in GVHD. The feasibility of induction of GVL-like effects by MHC non-restricted effector cells, such as that observed by CMI, most likely through cytokine-activated NK cells, seems promising because such effector mechanisms may be utilized clinically through either adoptive transfer of in vitro-activated lymphocytes or activation of lymphocytes in vivo by administration of cytokines such as IL2 and alpha IFN. Similarly, induction of CCI following ABMT may permit establishment of GVL-like effects with no major risk of GVHD. Our animal models suggest that both approaches may be beneficial and perhaps even combined. From a practical standpoint, activation of antitumour effector cells in vivo is much more feasible, in comparison with the cumbersome and expensive technologies for large-scale in vitro manipulation of IL2-activated 'LAK' cells or tumour-infiltrating lymphocytes ('TIL') at dose ranges required for obtaining clinically meaningful responses. No less important is the fact that more potent immunotherapy may be inducible by cytokine combinations (such as IL2 and alpha IFN). We are currently investigating additional cytokine combinations in order to attempt to optimize antitumour effects inducible by allogeneic and syngeneic lymphocytes since it appears logical that amplifying in vivo antitumour responses by multiple cytokine combinations may yield better antitumour effects.

Animals↗
PubMed1991

Immunoglobulins A, G, and M to cytomegalovirus during recurrent infection in recipients of allogeneic bone marrow transplantation.

Occurrence and significance of specific IgA and IgM to cytomegalovirus (CMV) in recurrent CMV infection was evaluated in 21 allogeneic T lymphocyte-depleted bone marrow transplantation (BMT) recipients who had been previously CMV seropositive. Of 17 patients with CMV infection, viruria was detected in 94%, CMV-specific IgA in 88% and IgM in 76%, and a fourfold rise in IgG in 65%. The median time between BMT and detection of viruria was 69 days, of IgA 70, of IgM 62, and of IgG 88 days. The IgM and IgA responses lasted for 14 and 30 days (median time), whereas high IgG titers persisted. Twelve patients developed CMV disease; in these the appearance of viruria, IgA, and IgM preceded the rise of IgG (P less than .02). CMV-specific IgA and IgM are valuable diagnostic tools in BMT recipients with recurrent CMV infection.

Adolescent↗
PubMed1991

New developments in bone marrow transplantation.

A better understanding of the immunobiology after transplantation and of the available recombinant cytokines that enhance hematopoietic reconstitution following autologous and allogeneic bone marrow transplantation is likely to result in safer application of bone marrow transplantation. Residual tumor cells escaping chemotherapy or chemoradiotherapy given in the course of autologous and allogeneic bone marrow transplantation are still a barrier to complete eradication of malignancy. Recent experiments in animal models of human disease suggest that minimal residual disease can be controlled by an innovative therapy consisting of the administration of cytokines such as recombinant human interleukin-2 and interferon-alpha. Moreover, graft versus leukemia-like effects are induced in conjunction with autologous and allogeneic bone marrow transplantation by administration of allogeneic immunocompetent lymphocytes and recombinant interleukin-2 following bone marrow transplantation and especially by combined administration of allogeneic lymphocytes and recombinant interleukin-2. Similar approaches are currently being investigated in humans with encouraging preliminary results. Overall, our data suggest that eradication of the last tumor cell is neither feasible nor necessary for achieving operational cure. Control of minimal residual disease by activation of anticancer effector cells today seems closer than ever and we are optimistic that further advances in immunotherapy will be applicable to clinical practice in the near future.

Animals↗
PubMed1991

Recombinant human superoxide dismutases: production and potential therapeutical uses.

In many pathological situations, tissue damage is caused by cellular generation of superoxide free radicals (O2-). These active species are generated during post-ischemic reperfusion of organs, in hyperoxic tissue, during acute and chronic inflammation and during exposure to ionizing radiation. Exogenous superoxide dismutase (SOD) was shown to significantly prevent such damage. The genes for human cytosolic Cu/ZnSOD and mitochondrial MnSOD were cloned and introduced into an E. coli expression system. The proteins were expressed in high yields and purified to homogeneity, yielding pharmaceutical-grade materials. These enzymes were used in a variety of in vivo animal models for the demonstration of their protective effects against oxidative damage. Comparative pharmacokinetic studies in rats have revealed that the half-life of Cu/ZnSOD was 6-10 min., while that of MnSOD was 5-6 hours, thus indicating that MnSOD may be superior to Cu/ZnSOD for the treatment of chronic diseases. Indeed, MnSOD was found to be effective as an anti-inflammatory agent in the rat carrageenan induced paw edema acute inflammation model. Both enzymes were also effective in ameliorating post-irradiation damage in mice exposed to whole-body or localized chest X-ray radiation.

Animals↗
PubMed1991

The effect of total or partial T lymphocyte depletion on susceptibility to influenza virus infection and development of antiviral immunity in lethally irradiated mice reconstituted with immune syngeneic bone marrow grafts.

In a previous study, we showed that lethally irradiated mice reconstituted with bone marrow (BM) enriched with spleen cells obtained from A/PR8/34 influenza virus-immune donors had an improved survival rate compared to the survival seen in recipients of naive BM, immune BM or T cell-depleted BM obtained from immune mice. Our purpose was to determine which cell population was responsible for this effect. We therefore compared the resistance to influenza virus of lethally irradiated BALB/c mice reconstituted with BM from immune donors enriched with 20% spleen cells following either incubation with anti-Thy-1, anti-Lyt-2 or anti-L3T4 monoclonal antibodies prior to transplantation, thereby leading to in vivo depletion of antibody-treated lymphocyte subsets. Mice were infected with influenza virus 1 day after BM transplantation. Equal survival rates were observed in recipients of unmanipulated BM and spleen cells obtained from immune donors and recipients of similar inocula treated with monoclonal anti-helper (L3T4) or anti-cytotoxic/suppressor (Lyt-2) antibodies prior to inoculation. The survival rate of all these groups was increased in comparison with mice receiving anti-Thy-1 treated BM and spleen cells, suggesting that both L3T4 and Lyt-2 T cell subsets play a role in protection against virus infections.

Animals↗
PubMed1991

Immune response to polio vaccination in bone marrow transplant recipients.

Following a small outbreak of poliomyelitis which occurred in the summer of 1988 in Israel, two sequential doses of inactivated polio vaccine (IPV) were administered to 42 bone marrow transplant (BMT) recipients (aged 2-50 years) who were 6-96 months (median 16 months) after transplantation. Prior to vaccination, only 68-80% patients (n = 42) had protective (greater than or equal to 4) antibody levels against the three serotypes of poliovirus, compared with 92-96% (n = 25) before BMT (p = 0.02 for types 1 and 3). After the second dose of IPV, 89-98% (n = 27) of the recipients had protective antibody levels. The pre-vaccination antibody titers were lower than before BMT (p = 0.006, 0.0007 and 0.0008 for types 1,2 and 3, respectively). After the first dose of IPV, antibody titers rose in the 42 patients (p = 0.002, 0.043 and 0.002 for types 1, 2 and 3, respectively) and following the second dose, a further increase in antibody levels was noted. Regression analysis revealed that graft-versus-host disease, pre-BMT polio antibody titers, age and type of transplantation (allogeneic versus autologous) were significant explanatory variables for the specific antibody levels, while the time lapse between BMT and vaccination, and primary disease proved of no significance. Vaccination against poliovirus after BMT is advocated, as it reinstates and raises the lost specific humoral immunity.

Adolescent↗
PubMed1991

Effect of exogenous recombinant human granulocyte and granulocyte-macrophage colony-stimulating factor on neutrophil function following allogeneic bone marrow transplantation.

Functional activity of peripheral blood granulocytes was assessed in seven patients and in their normal donors following allogeneic bone marrow transplantation (BMT). Functions studied included superoxide generation (O2-), intracellular killing of Staphylococcus aureus, phagocytosis, and killing of Candida albicans. Neutrophils were tested following preincubation with 300 pM granulocyte-macrophage colony-stimulating factor (GM-CSF), 1.2 nM granulocyte colony-stimulating factor (G-CSF), or buffered solution (diluent) as control. Our data indicate that following BMT, both recipients and their normal donors show GM-CSF- and G-CSF-induced increases in: 1) O2- production in response to fMet-Leu-Phe (fMLP), 2) killing of S. aureus, and 3) phagocytosis of C. albicans. In two patients that showed low candidacidal activity, GM-CSF and G-CSF markedly enhanced the cytotoxic activity of the cells. Our studies indicate that GM-CSF and G-CSF increase "oxygen-dependent" oxidative activities in neutrophils from BMT recipients and their normal donors and enhance the antimicrobial activity of the cells.

Adult↗
PubMed1991

Transient elevation of serum lactic dehydrogenase following autologous bone marrow transplantation.

Transient elevated levels of serum lactic dehydrogenase (LDH) were reported immediately following autologous bone marrow transplantation consecutively in 15 patients. Isoenzyme 2 was the predominant elevated isoenzyme of LDH, suggesting that the source of LDH is either hemolysis of RBCs, which occurs during freezing and thawing of bone marrow in the bags and in vivo following infusion of residual dimethyl sulfoxide.

Adolescent↗
PubMed1991

The effect of in vitro T lymphocyte depletion on generation of IL2-activated cytotoxic cells.

The effect of immunocompetent lymphocyte depletion on precursors and effector cells of IL2 activated non-MHC restricted cytotoxic cells (LAK) generated from bone marrow (BM) or peripheral blood was investigated. Lymphocyte depletion was carried out by using Campath-1, a monoclonal rat anti-human lymphocyte antibody recognizing CDW52, that binds human complement and is used routinely in clinical bone marrow transplantation (BMT). The results indicate that LAK precursors derived from BM cells are sensitive to Campath-1 treatment, while a variable degree of sensitivity was demonstrated in LAK precursor cells derived from peripheral blood. In contrast, effector LAK cells generated in vitro were shown to be resistant to treatment with Campath-1 and complement. We hypothesize that if indeed IL2-dependent non-MHC restricted cytotoxic cells play a role in vivo in the immediate post-BMT period, a T lymphocyte depletion procedure such as the Campath-1 may have the capacity to reduce, at least temporarily, the graft-versus leukemia effects mediated by such anti-tumor effector mechanisms.

Animals↗
PubMed1990

The use of parabiosis for investigating the mechanism of transplantation tolerance in bone marrow chimeras induced by total lymphoid irradiation.

The mechanism of transplantation tolerance in total lymphoid irradiation (TLI)-induced semiallogeneic bone marrow chimeras without clinical evidence of graft-versus-host disease (GVHD) was investigated using the technique of surgical parabiosis. When held in parabiosis with normal BALB/c mice, BALB/c---- (BALB/c x C57BL/6)F1 (BALB----F1) chimeras survived 7-9 days, significantly (P less than 0.001) shorter than the 12-19 day survival of normal F1 hybrids kept in parabiosis with normal BALB, and in contrast to indefinite (greater than 200 days) survival of syngeneic BALB parabiotic partners. When C57 skin grafts were placed on BALB mice held in parabiosis with BALB----F1 chimeras, C57 skin grafts survived 50-60 days, in contrast to 10-14 days in normal BALB recipients (P less than 0.001). Lethal GVHD, induced in sublethally irradiated F1 recipients by 10(7) BALB spleen cells, could not be delayed or prevented by cotransfer of 10(7) to 30 x 10(7) tolerant BALB spleen cells obtained from stable BALB----F1 chimeras. GVHD reactivity of BALB spleen cells isolated from BALB----F1 chimeras tolerant of C57 could not be recovered by depletion of Lyt2 cytotoxic suppressor cells. Taken together, in the absence of suppressive capacity by suppressor cells, these data support functional clonal deletion as the primary mechanism responsible for the maintenance of unresponsiveness to host alloantigens in TLI-induced semiallogeneic chimeras, since no protection against induction of GVHD could be documented in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗