Biomedical subjects

D D Schoof

Publications and source records attributed to D D Schoof.

32 records · Page 2Linked to original sources

PubMed1991

Reduction of smooth muscle hyperplasia in vein grafts in athymic rats.

While developing an animal model of a vascular malformation, we found that two doses of cyclosporin A significantly reduced the smooth muscle cell hyperplasia observed in vein-arterial interposition grafts in Sprague-Dawley rats. Therefore, we hypothesized that T cells may either produce or augment a mitogen for vascular smooth muscle cells. To further investigate this, we quantitated the extent of smooth muscle cell hyperplasia in the vein grafts of athymic nude rats that lack mature, functioning T cells. Male Sprague-Dawley rats (275 to 350 gm) and athymic nude rats were anesthetized, and a segment of the superficial epigastric vein was placed into the transected femoral artery using microsurgical techniques. Sprague-Dawley rats (N = 9) and athymic nude rats (N = 5) undergoing vein grafting received 30 mg/kg cyclosporin A intraperitoneally, intraoperatively and 24 hours later. Sprague-Dawley rats (N = 7) and athymic nude rats (N = 6) that had vein grafts were not treated with cyclosporin A. Animals were killed at either 3 weeks or 6 weeks and histologic sections were taken from the middle of the graft to avoid clamp-induced trauma. At 3 weeks, untreated vein grafts in Sprague-Dawley rats exposed to arterial pressure exhibited a nine-fold increase in smooth muscle hyperplasia compared with the preoperative vein. Treatment of Sprague-Dawley rats with cyclosporin A resulted in a 57% reduction of smooth muscle hyperplasia (p less than 0.05). Vein grafts from athymic nude rats exhibited a 51% reduction in smooth muscle hyperplasia (p less than 0.05). Sprague-Dawley rats killed at 6 weeks revealed a recovery of smooth muscle hyperplasia equivalent to an untreated Sprague-Dawley vein graft at 3 weeks. Inhibition of smooth muscle hyperplasia persisted for 6 weeks in the athymic nude rats. Cyclosporin A administration or T cell deficiency in athymic nude rats decreases the smooth muscle hyperplasia observed in venous grafts exposed to arterial pressure. This finding provides evidence for a possible role of T cells in the regulation of cell growth in the vascular wall.

Animals↗

PubMed1990

Solid-phase anti-CD3 antibody activation of murine tumor-infiltrating lymphocytes.

Seventeen consecutive s.c. murine tumors, derived from a sarcoma and a colon adenocarcinoma, were cultured in the presence of recombinant interleukin 2 (rIL-2) for growth of tumor-infiltrating lymphocytes (TIL). Identical cultures were activated by solid-phase monoclonal antibody directed against the murine CD3 epsilon-chain, in conjunction with rIL-2. Forty-eight h later, cells were replaced in rIL-2 alone. Proliferation of anti-CD3-stimulated cultures was 1- to 17-fold greater than those cultured with rIL-2 alone (P less than 0.05). Both culture conditions yielded TIL which stained greater than 80% Thy-1.2+/Lyt-2+ (P greater than 0.05), less than 7% Thy-1.2+/L3T4+ (P greater than 0.05). Regardless of culture condition, longitudinal studies of in vitro cytotoxicity generated from 10 TIL preparations revealed no significant differences between the ability of TIL to lyse the murine natural killer-sensitive line YAC or heterologous or autologous tumor (P greater than 0.05). In vivo antitumor activity of TIL was tested by the adoptive transfer of suboptimal doses of TIL plus systemic rIL-2 to mice with pulmonary micrometastatic disease. No difference in tumor regression was noted between the TIL cultured with anti-CD3 plus rIL-2 or with rIL-2 alone (P greater than 0.05). Anti-CD3 stimulation of murine TIL cultures significantly increases lymphocyte cell yield without alteration of their phenotype, in vitro tumoricidal activity, or in vivo therapeutic effect.

Animals↗

PubMed1990

Activation of human tumor-infiltrating lymphocytes by monoclonal antibodies directed to the CD3 complex.

We have used high concentrations of recombinant-methionyl human interleukin 2 (rIL-2) for the initial growth and expansion of human tumor-infiltrating lymphocytes (TIL). Early in the life of the TIL bulk culture, cytotoxicity was non-major histocompatibility complex restricted. Under these culture conditions antitumor cytotoxicity was observed to decline with increasing age of the bulk culture. In addition, TIL became refractory to rIL-2-induced expansion. We have used solid-phase anti-CD3 antibodies for TIL activation followed by culture in reduced concentrations of rIL-2 to reactivate TIL previously grown in high concentrations of rIL-2. TIL refractory to rIL-2 in terms of growth and antitumor cytotoxicity proved sensitive to anti-CD3 activation. The use of solid-phase anti-CD3 was also more effective than high concentrations of rIL-2 in the expansion of TIL when used at the start of culture. Finally, TIL could be induced to secrete IL-2 following solid-phase activation with anti-CD3. These data suggest that human TIL are susceptible to activation by signals directed at the CD3 complex of the TIL cell surface.

Antibodies, Monoclonal↗

PubMed1989

Human tumor-infiltrating lymphocyte (TIL) cytotoxicity facilitated by anti-T-cell receptor antibody.

Long-term growth of tumor-infiltrating lymphocytes (TIL) in high concentrations of rIL-2 is required for generation of therapeutic numbers of cells for adoptive immunotherapy of human cancer. Under these conditions rIL-2 promotes both anti-tumor cytotoxicity and lymphocyte growth from tumors of several histological types. In a series of 16 consecutive tumors, studies of TIL-mediated cytotoxicity against different tumor targets were characterized by an initial strong tumor-non-specific cytotoxicity. With time, TIL bulk cultures became non-cytotoxic against all targets (median time = 38 days). Non-cytotoxic TIL bulk populations were capable of mediating strong cytotoxic responses if pre-treated with anti-T-cell antigen receptor antibody (TcR) before addition to targets. TIL populations were not, however, uniformly susceptible to anti-TcR-mediated cytotoxicity. Anti-TcR-mediated cytotoxicity was confined to CD8+ bulk populations (defined as populations with a CD4/CD8 ratio less than 1), with virtually no cytotoxicity observed in CD4+ populations (CD4/CD8 ratio greater than 2, (p less than 0.01). Both CD4 and CD8 populations expressed TcR antigen reactive with anti-TcR antibody. These results indicate that, despite poor in vitro anti-tumor cytotoxicity in short-term assays, CD8+ TIL are fully competent cytotoxic effector cells when subjected to strong activation signals via the TcR complex. In addition, these results imply that adoptively transferred CD4+ populations of TIL have in vivo biologic functions quite distinct from those of CD8+ populations and, further, that disparate clinical outcomes could reasonably be expected from the adoptive transfer of either population alone.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1989

Activation of eosinophils in cancer patients treated with IL-2 and IL-2-generated lymphokine-activated killer cells.

Of 16 patients, a total of 13 who received IL-2 and autologous IL-2-generated lymphokine-activated killer LAK cells developed eosinophilia late during the course of treatment. To understand the direct or indirect effects of IL-2 on eosinophils, the physical and functional characteristics of the late-treatment eosinophils were compared to those of early-treatment and control eosinophils. Late-treatment eosinophils differed from early-treatment and control eosinophils in the following respects: they had somewhat reduced density, hypersegmented nuclei, eosinophil cationic protein converted from the storage form to the secretory form, and a greater than 200% increased ability to kill larvae of Schistosoma mansoni by an antibody-dependent mechanism (cytotoxic function). In vitro, IL-2 (1000 U/ml in medium as used to culture LAK cells) did not affect the cytotoxic function of eosinophils from cancer patients or from control subjects. However, LAK cell-conditioned medium enhanced the cytotoxic function of eosinophils from early-treatment cancer patients and from normal subjects by greater than 150%. Thus, eosinophils late in the course of IL-2/LAK cell treatment undergo physical changes and become functionally activated. The involvement of IL-2 in these changes is probably indirect, as an inducer of factors that enhance eosinophil function.

Antibody-Dependent Cell Cytotoxicity↗

PubMed1989

Ibuprofen causes reduced toxic effects of interleukin 2 administration in patients with metastatic cancer.

Metastatic cancer was treated with interleukin 2 and lymphokine-activated killer cells with the addition of the cyclooxygenase inhibitor ibuprofen in an attempt to reduce side effects in 13 patients (eight male and five female). Twenty-six patients treated with only interleukin 2 and lymphokine-activated killer cells formed the control group. After interleukin 2 administration, a significantly increased number of lymphokine-activated killer cells were transfused in ibuprofen-treated patients. Cytotoxic effects were not significantly different in the treated and untreated groups. With regard to cell phenotype, both groups of patients manifested significant activation of the immune system as measured by T10 and OK1a. Symptom scores were dramatically reduced in patients treated with ibuprofen. Temperature above 37 degrees C were rare. Ibuprofen did not significantly alter rate of response in this immunotherapy trial (38% vs 42%). Ibuprofen is now routinely used in all of our current immunotherapy trials.

Cells, Cultured↗

PubMed1989

Immunomodulatory effects of systemic low-dose recombinant interleukin-2 and lymphokine-activated killer cells in humans.

The adoptive immunotherapy of human cancer using lymphokine-activated killer (LAK) cells in combination with high-dose systemic recombinant interleukin-2 (rIL-2) has been associated with global changes in several hematological and immunological parameters while imposing profound toxicity on patients. We have evaluated an alternative LAK cell therapy utilizing low-dose systemic rIL-2 is also characterized by significant changes in immunological and hematological parameters, which are qualitatively similar to those induced by high-dose rIL-2. Low-dose systemic rIL-2, given by i.v. bolus, is cleared to baseline levels within 240 min of administration. The induction of lymphocytosis and eosinophilia, which has characterized other protocols, is also a feature of this protocol. In addition, low-dose systemic rIL-2/LAK cell immunotherapy results in increased peripheral blood mononuclear cell (PBMC) expression of T-cell activation markers such as OKIa, OKT10 and IL-2 receptor. PBMC sampled approximately 100 h after the final infusion of LAK cells demonstrated a statistically significant increase in their ability to kill natural killer (NK)-sensitive and NK-resistant cell lines such as K562 and Daudi compared to baseline values (P less than .05). These data suggest that rIL-2-based immunotherapy using low-dose rIL-2 is capable of inducing quantitative hematological and immunological changes while (in combination with LAK cells) retaining the ability to mediate tumor regression in vivo.

Adjuvants, Immunologic↗

PubMed1988

Adoptive immunotherapy of human cancer using low-dose recombinant interleukin 2 and lymphokine-activated killer cells.

The adoptive transfer of recombinant-methionyl human interleukin 2 (rIL-2)-activated autologous peripheral blood mononuclear lymphokine-activated killer (LAK) cells to cancer patients is being evaluated as an alternative to conventional cancer therapy. We have independently developed an alternative regimen to previously reported adoptive immunotherapy protocols using rIL-2 and LAK cells which features the prolonged administration of low-dose rIL-2 (30,000 units/kg) and an automated, entirely enclosed system of peripheral blood cell procurement, culture, harvest, and reinfusion of activated cells. The cell culture system was tested with a murine tumor model in which LAK cells generated in plastic culture bags were reinfused into tumor-bearing mice. Tumor regression was as effective with cells activated in the bags as in conventional culture flasks. Twenty-eight cancer patients were treated for 5 consecutive days with low-dose rIL-2, followed by leukapheresis, infusion of LAK cells, and prolonged IL-2 administration. At least 50% tumor regression was observed in 46% of all patients treated. These data imply that human peripheral blood mononuclear cells retain fully their capacity for rIL-2-induced activation and effector cell function under this alternative approach, and further, that a low-dose rIL-2 regimen with markedly reduced toxicities can be as effective as high-dose rIL-2 regimens if low-dose rIL-2 is given for a prolonged period of time following LAK cell infusion.

Adult↗

PubMed1988

Large scale production and purification of paraquat and desipramine monoclonal antibodies and their Fab fragments.

We describe the rapid, large scale purification of Fab fragments from mouse monoclonal antibodies. Antibodies against two clinically important and often fatal toxins, paraquat and desipramine, were isolated from mouse ascites fluid by preparative high performance hydroxylapatite (HPHT) or ion exchange (DEAE) high performance liquid chromatography. A competitive inhibition ELISA was used to determine the cross-reactivity of the antibody with analogs of the antigens. Papain digests of the IgGs were subjected to further HPHT followed by Sephadex G-100 chromatography to yield homogeneous Fab fragment preparations. The high purity of these preparations, demonstrated by SDS polyacrylamide gel electrophoresis, has only been achieved previously by affinity chromatography. Intrinsic association constants for the intact IgG and the Fab fragment--antigen interactions, determined by competitive inhibition ELISA, were similar. This indicates that antigen-binding activity was conserved during the production and purification of the Fab fragments.

Animals↗

PubMed1988

A new regimen of interleukin 2 and lymphokine-activated killer cells. Efficacy without significant toxicity.

Adoptive immunotherapy with high-dose interleukin 2 and lymphokine-activated killer (LAK) cells has proved to be successful in the treatment of some patients with metastatic cancer, but not without a significant degree of associated toxic effects. The primary goal of this study was to substantially reduce the toxicity of this complex and expensive treatment, while maintaining or improving efficacy. To this end, 29 patients were treated with LAK cells in conjunction with a low-dose regimen of interleukin 2 and a prolonged period of administration following LAK cell infusion. This protocol resulted in a considerable reduction in toxicity, as compared with that described in previous studies, without compromising the efficacy. This study offers further confirmation that adoptive immunotherapy of metastatic cancer can be clinically beneficial to patients for whom no other effective therapy is presently available.

Adult↗

PubMed1987

Partial characterization of chicken spleen cell culture supernatants stimulated with Staphylococcus aureus.

The role of accessory cells in the proliferative response of chicken spleen cells to Staphylococcus aureus Cowan I (SAC) was examined. It was found that chicken spleen cells cultured with SAC produced a soluble molecule capable of causing proliferation when culture supernatants were added to spleen cells. The molecules responsible for this activity were stable in terms of exposure to extremes of heat and pH. Gel filtration of culture supernatants revealed biological activity, over a broad range of molecular weights, as measured by spleen cell proliferation. Similar findings were obtained when SAC was sonicated and evaluated following gel filtration. Exposure of culture supernatants to trypsin abrogated biological activity. The pivotal role of adherent cells in the generation of biologically active molecules is suggested by the ability of peritoneal exudate cells incubated with SAC to produce biologically active supernatants. In addition, the proliferative response of spleen cells to SAC was sensitive to chloroquine.

Animals↗

PubMed1987

Repeated hemoperfusion and continuous arteriovenous hemofiltration in a paraquat poisoned patient.

Prompt hemodialysis or hemoperfusion can be of value during the first 24 hours after paraquat ingestion particularly when the patient has developed acute renal failure. However, many cases of paraquat poisoning occur in areas where hemoperfusion facilities are unavailable. In contrast, continuous arteriovenous hemofiltration (CAVH) could be instituted easily. We have measured the removal of paraquat from the body by CAVH in a 46 year old male cane farmer who ingested 70 ml, 20% paraquat and died twelve days later from pulmonary fibrosis. Renal failure developed rapidly. Concentrations of paraquat were measured by an indirect competitive ELISA using a murine paraquat monoclonal IgG antibody. Hemoperfusion was performed daily for five days, beginning 78 hours post-ingestion. By 180 hours, when the patient was in respiratory failure, hemoperfusion was replaced with CAVH which was continued for 46 hours. During this time interval, 1.1 mg paraquat was recovered in the hemofiltrate and 1.56 mg paraquat in the urine. The extraction of paraquat by the hemofilter was close to 100%. The plasma clearance of paraquat across the hemofilter was 6.1 ml/min and the renal clearance was 8.2 ml/min. The mean hemoperfusion clearance of paraquat was 50 ml/min and the total amount of paraquat removed by the 34 hours of hemoperfusion was 9 mg. Because of the relative ease with which CAVH can be performed, its low cost, compared to that of hemoperfusion or hemodialysis, and the continuous nature of the procedure, CAVH may be worth considering in paraquat poisoning. It could be used particularly in those patients who have developed renal failure or while patients are being prepared for hemoperfusion.

Hemofiltration↗

PubMed1986

The role of soluble protein A in chicken spleen cell activation.

Soluble protein A (SpA) caused chicken spleen cell proliferation despite considerable evidence that SpA has no binding affinity for avian immunoglobulin (Ig). This biological activity was examined by several approaches. SpA-stimulated spleen cell cultures demonstrated no difference in proliferative responses regardless of the addition of human gamma globulin (HGG) or keyhole limpet hemocyanin. Adsorbents composed of HGG or hemoglobin were equally ineffective in abrogating the ability of SpA to induce spleen cell proliferation. In addition, ion exchange purified SpA was observed to induce comparable levels of spleen cell proliferation as ion exchange-affinity purified preparations. The lymphocyte subpopulation responsible for the observed proliferative response to SpA resides in the nylon wool adherent population. Nylon wool nonadherent lymphocytes failed to proliferate to SpA, but did proliferate in response to phytohemagglutinin as did nylon wool adherent cells. These data indicate that SpA is not responsible for the observed biological activity and suggest that components from Staphylococcus aureus other than SpA copurify during the preparation of SpA and are responsible for the activation of spleen cells.

Animals↗

PubMed1984

B cell activation in chickens induced by Staphylococcus aureus.

Conventional mammalian polyclonal B cell activators were evaluated for activity in chicken spleen and peripheral blood lymphocyte (PBL) cultures. Although lipopolysaccharide was found to have a marginal influence on proliferation, two strains of the bacterium Staphylococcus aureus (Cowan I and Wood 46 strains) induced moderate proliferation in both spleen and PBL cultures. In spleen cell cultures the proliferating cell population was identified as the B cell. The mitogenic response required the presence of adherent cells since their removal eliminated the response. Evidence of in vitro polyclonal immunoglobulin synthesis could not be obtained. However, when administered intravenously, S. aureus induced polyclonal immunoglobulin synthesis.

Animals↗