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L Nadler

Publications and source records attributed to L Nadler.

At least 19 recordsLinked to original sources
PubMed1999

Muc-1 core protein is expressed on multiple myeloma cells and is induced by dexamethasone.

Monoclonal antibodies (MoAbs) that selectively identify Muc-1 core protein (MoAbs DF3-P, VU-4H5) determinants were used to identify the Muc-1 glycoform present on 7 multiple myeloma (MM) cell lines, 5 MM patient plasma cells, 12 MM patient B cells, as well as 32 non-MM cell lines and normal hematopoietic cells. Flow cytometry studies demonstrated that all MM cell lines, MM patient plasma cells, and MM patient B cells expressed Muc-1 core protein epitopes. Circulating B cells from 4 normal donors also expressed Muc-1 core protein. In contrast, Muc-1 core protein was absent on 28 of 32 non-MM neoplastic cell lines, 17 of which expressed Muc-1. Splenic and tonsillar B cells, CD34(+) stem cells, resting T cells, and bone marrow plasma cells obtained from normal donors both lacked Muc-1 glycoforms. We next studied the effects of estrogen, progesterone, and glucocorticoid receptor agonists and antagonists on Muc-1 expression, because consensus sequences for the response elements of these steroids are present on the Muc-1 gene promoter. These studies showed that dexamethasone (Dex) induced Muc-1 expression on MM cell lines, as determined by both flow cytometry and Western blot analyses. Dex also induced upregulation of Muc-1 on prostate and ovarian cancer cell lines. Time and dose-response studies demonstrated that Dex induced maximal cell surface Muc-1 expression by 24 hours at concentrations of 10(-8) mol/L. Dex induced Muc-1 upregulation could be blocked with a 10-fold excess of the glucocorticoid receptor antagonist RU486, confirming that Dex was acting via the glucocorticoid receptor. No changes in Muc-1 expression were observed on MM cells treated with estrogen and progesterone receptor agonists and antagonists or with RU486. These studies provide the framework for targeting Muc-1 core protein in vaccination and serotherapy trials in MM. In addition, the finding that Muc-1 expression on MM cells can be augmented by Dex at pharmacologically achievable levels suggests their potential utility in enhancing treatments targeting Muc-1 in MM.

Dexamethasone↗
PubMed1997

Cyclophosphamide, doxorubicin, vincristine, prednisone dose intensification with granulocyte colony-stimulating factor markedly depletes stem cell reserve for autologous bone marrow transplantation.

Hematopoietic growth factors allow dose escalation of chemotherapy. This approach may potentially reduce the quality and quantity of hematopoietic stem cells. The capacity of stem cells recovered after dose intensification to support myeloablative therapy is unknown. In patients with previously untreated advanced follicular lymphoma, trilineage hematopoietic engraftment was compared in two sequential trials of induction therapy (standard dose cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP] without growth factors or dose intensification CHOP supported by granulocyte colony-stimulating factor [G-CSF ]) followed by identical myeloablative therapy and autologous stem cell support. Neutrophil, platelet, and red blood cell (RBC) engraftment were compared on days 100, 180, and 360 after stem cell reinfusion. Despite similar patient characteristics including reinfusion of comparable numbers of marrow mononuclear cells, after stem cell transplantation, a highly significant prolongation of neutrophil and platelet engraftment was seen in patients who received high dose CHOP and G-CSF in comparison to standard dose CHOP. These findings suggest that dose intensified chemotherapy and G-CSF recruited stem cells into a proliferative phase and that G-CSF allowed retreatment at a time when stem cells were susceptible to damage by cytotoxic therapy. Such inadequate hematologic engraftment after myeloablative therapy might be avoided by either shortening the time that growth factor support is administered, lengthening the interval between cycles, or attempting to repetitively harvest additional stem cells either from the marrow or peripheral blood. Therefore, intensification of chemotherapy with growth factor support must be used with caution if stem cells are to be used to support myeloablative therapy.

Adult↗
PubMed1997

CD6-depleted allogeneic bone marrow transplantation for acute leukemia in first complete remission.

The appropriate timing of bone marrow transplantation (BMT) for adults with acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) is controversial. Although allogeneic transplantation results in a lower risk of disease recurrence than intensive chemotherapy alone, overall outcome following BMT may not be improved due to the higher incidence of therapy-related fatal complications, frequently as a result of the development of graft-versus-host disease (GVHD). Selective T-cell depletion of donor marrow can reduce the incidence of GVHD and thereby limit transplant-related toxicity. Herein we report the risk of GVHD, incidence of transplant related mortality (TRM), likelihood of disease relapse, and overall survival in adult patients undergoing BMT with CD6 depleted allogeneic marrow for acute leukemia in first remission. Forty-one consecutive allogeneic transplants were performed on patients with acute leukemia and high-risk features (28 AML, 13 ALL) using T12 monoclonal antibody and complement to remove CD6+ T cells from donor marrow. No pre- or posttransplant immune suppressive medications for GVHD prophylaxis were administered. The actuarial estimated risk of grade 2 to 4 acute GVHD was 15% in patients receiving HLA identical grafts. Chronic GVHD developed in five patients. The estimated risk of TRM for patients in first complete remission was 5% at Day +100 and 16% at 2 years. Fatalities attributable to infection with cytomegalovirus or Epstein-Barr virus occurred in only three patients. Estimated probabilities of relapse, overall survival, and event-free survival at 4 years were 25%, 71%, and 63%, respectively. No significant differences in GVHD, TRM, relapse rate, or survival was observed for patients with AML compared with those with ALL. Allogeneic transplantation with CD6 depleted bone marrow is effective in consolidating remissions of high-risk patients with acute leukemia in first remission without excessive toxicity.

Acute Disease↗
PubMed1997

CD6+ T cell depleted allogeneic bone marrow transplantation from genotypically HLA nonidentical related donors.

The widespread use of allogeneic bone marrow transplantation (BMT) is limited by the availability of suitable donors. Recent attempts to expand the donor pool by employing HLA matched unrelated marrow have been partially successful. However, severe graft-versus-host disease (GVHD) and graft failure remain obstacles and contribute to the substantial morbidity and mortality associated with matched unrelated BMT. The use of genotypically nonidentical related or unrelated donor marrow could have wider application if problems associated with GVHD could be overcome. Based upon the low incidence of GVHD in recipients of HLA-matched related donor marrow depleted of T cells with T12, an anti-CD6 monoclonal antibody, we applied this approach to 27 adult recipients of HLA mismatched related bone marrow. Ten patients received marrow mismatched at 2 HLA loci, 13 received 1 antigen mismatched marrow, and 4 received phenotypically identical marrow from a non-sibling. Immediately prior to admission, patients were treated with total lymphoid irradiation (750-1050 cGy) to suppress host derived. T lymphocytes capable of mediating graft rejection. The ablative regimen consisted of cyclophosphamide (60 mg/kg x 2 days) followed by total body irradiation (1400 cGy in 7 fractions over 4 days). Patients then received marrow depleted of T cells with T12 (CD6) plus complement. No immune suppressive medications were administered to prevent GVHD. Twenty-four of 27 patients displayed stable hematologic engraftment, achieving an absolute neutrophil count of 0.5 x 10(9)/L at a median of 19 days post-BMT. Degree of HLA disparity did not influence engraftment. Among engrafting patients, grades 2-4 acute GVHD occurred in 40% and grade 3-4 GVHD in 8%. Chronic GVHD developed in 5 patients. Patients mismatched at 2 loci were more likely to develop GVHD than those mismatched at 0-1 loci (logrank, p = .04). Disease relapse has occurred in only 3 patients receiving mismatched marrow. Estimated overall survival for mismatched patients is 56% at 2 years and is independent of HLA disparity. Among the patients transplanted for chronic myelogenous in stable phase or acute leukemia in first remission, estimated event free survival is 69% at 2 years compared to 20% for patients with more advanced disease. Our results suggest that transplantation of mismatched related marrow using modalities designed to reduce GVHD without immune suppressive medication (CD6 depletion) is feasible and should prompt wider investigation into the extended families of patients in the search for potential marrow donors. This approach also merits investigation in recipients of matched unrelated marrow as a potential means of reducing transplant-related toxicity.

Adolescent↗
PubMed1995

Ciprofloxacin versus trimethoprim/sulfamethoxazole for prophylaxis of bacterial infections in bone marrow transplant recipients: a randomized, controlled trial.

PURPOSE: To compare the efficacy and safety of ciprofloxacin (CIP) and trimethoprim/sulfamethoxazole (TMS) for the prevention of bacterial infections in patients who received bone marrow transplantation (BMT) for the treatment of solid and hematopoietic neoplasms. PATIENTS AND METHODS: Adult inpatients about to undergo BMT for lymphoma, leukemia, or solid tumors were enrolled onto a prospective, randomized, double-blinded, controlled trial that compared CIP (750 mg orally twice per day) with TMS (160 mg trimethoprim and 800 mg sulfamethoxazole orally twice per day). Subjects were stratified before randomization according to tumor and BMT type. Prophylaxis was begun within 96 hours of initiation of the BMT preparative regimen and continued until the onset of fever, signs or symptoms of infection, serious adverse effects, or recovery of the absolute granulocyte count (AGC) to > or = to 400/microL. RESULTS: Seventy-five CIP recipients and 71 TMS recipients were assessable for efficacy. No difference was noted between the two groups in occurrence of fever during neutropenia, time to onset of first fever, or overall infection rates. Ten bacteremias occurred in CIP recipients versus six in TMS recipients (P = .43). Ten episodes of Clostridium difficile enterocolitis occurred in TMS recipients versus no episodes in CIP recipients (P = .001). Four infections caused by gram-negative bacilli, including one bacteremia, occurred in TMS recipients versus none in CIP recipients (P = .06). No differences were noted in the incidence of rash or organ toxicity. TMS recipients had longer durations of granulocytopenia at AGC levels < or = to 500/microL and < or = to 100/microL than did CIP recipients (P = .08 for both comparisons). Mean peak and trough serum levels of CIP decreased significantly between weeks 1 and 2 of prophylaxis. CONCLUSION: CIP and TMS were equally safe and effective in the prevention of bacterial infections in BMT patients when the overall infection rate was used as the principal end point. TMS prophylaxis was associated with a higher incidence of C difficile enterocolitis and infections caused by gram-negative bacilli, as well as a trend toward prolongation of granulocytopenia.

Administration, Oral↗
PubMed1995

Monoclonal antibody-purged bone marrow transplantation therapy for multiple myeloma.

This report describes the clinical characteristics, treatment associated toxicity, and follow-up of fifty-eight patients with plasma cell--dyscrasias treated with high dose chemotherapy and total body irradiation (TBI) at a single institution. Following TBI, 36 patients received anti-B cell monoclonal antibody (MoAb)-treated autologous bone marrow, 21 patients received anti-CD6 cell MoAb-treated allogeneic bone marrow to deplete T cells, and one patient received unpurged bone marrow from a syngeneic donor. Evaluation after high dose chemotherapy and bone marrow transplantation (BMT) demonstrated 26 complete responses (CR), 26 partial responses (PR), 2 non-responders, 1 not yet evaluated, and three toxic deaths. Fourteen of 36 patients who underwent autologous BMT are alive free from progression at 18 (range 5 to 68) months post transplant (post-BMT); of these, 11 remain in continuous complete response at 16 (range 5 to 68) months post-BMT. Seven of 21 patients who underwent allogeneic BMT are alive free from progression at 30 (range 4 to 44) months post-BMT; of these, three patients remain in continuous complete response at 43 (range 33 to 45) months post-BMT. These data suggest that high dose chemotherapy with TBI followed by MoAb purged BM can be performed with acceptable toxicity and high tumor response rates.

Adult↗
PubMed1994

Myeloablative therapy with autologous bone marrow transplantation as consolidation therapy for follicular lymphoma.

Since June 1985, 121 patients with follicular lymphoma aged 24-61 years (median 43) have received myeloablative therapy (cyclophosphamide: 60 mg/kg x 2, + total body irradiation: 200 cGy x 6) with autologous bone marrow transplantation (CY+TBI+ABMT) as consolidation of 2nd or subsequent remission. The marrow mononuclear cell fraction was treated in vitro with anti-CD20 alone and baby rabbit complement at St. Bartholomew's Hospital (SBH) and with the addition of anti-B5 and anti-CD10 at the Dana Farber Cancer Institute (DFCI) prior to reinfusion. There were 4 treatment related deaths, (nonengraftment 1, haemorrhage 1, systemic fungal infection 1, veno-occlusive disease 1). The median time for neutrophil recovery (> 0.5 x 10(9)/1) was 26 days (range 10 to 59 days), and for platelets (> 20 x 10(9)/1), 30 days (range 12 to 73 days). One patient did not engraft and 7 have had delayed recovery of red cells and platelets (> 3 months). Two other patients have subsequently developed acute myelogenous leukaemia and 5, evidence of myelodyplasia. Seventy-one patients continue in unmaintained remission between 3 months and 7 years, with a median follow up of 2.5 years. Forty-three have developed recurrent lymphoma; 98 remain alive. Freedom from progression was the same, irrespective of whether patients received CY + TBI + ABMT whilst in a complete or partial remission and did not depend on the specific remission in which treatment was given (2nd: 90 patients vs. > 2nd: 31 patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Effects of cyclosporin A, FK 506, and mycalamide A on the activation of murine CD4+ T cells by the murine B7 antigen.

The murine B7 (mB7) protein is a potent co-stimulatory molecule for the activation of murine CD4+ T cells. We have previously shown that stable mB7-transfected Chinese hamster ovary (CHO) cells synergize with either anti-CD3 monoclonal antibodies (mAb) or concanavalin A to stimulate T cell activation. In addition, mB7 can synergize with phorbol 12-myristate 13-acetate (PMA) to induce T cell activation in an alternative pathway. In the present report we describe the effects of three immunosuppressive drugs, cyclosporin A (CsA), FK 506, and mycalamide A on mB7-mediated T cell activation. The immunophilin ligands CsA and FK 506 block activation of murine CD4+ T cells by the combination of anti-CD3 mAb and CHO-mB7 cells but do not affect activation by CHO-mB7 cells and PMA. These results support the relevance of pharmacological studies of immunosuppressive compounds in the murine model prior to their application in man. In contrast to the effects of CsA and FK 506, mycalamide A blocks activation of murine CD4+ T cells by anti-CD3 mAb and mB7 as well as activation by mB7 and PMA. On a molar basis, mycalamide A appears to be at least 10-fold more potent than FK 506 which is 100-fold more potent than CsA. Because of its effects on multiple activation pathways and because of its potency, mycalamide A could have considerable therapeutic potential.

Animals↗
PubMed1992

Murine B7 antigen provides a sufficient costimulatory signal for antigen-specific and MHC-restricted T cell activation.

We have previously shown that the murine B7 (mB7) molecule, when expressed in Chinese hamster ovary cells in stable fashion, can costimulate with anti-CD3 mAb or Con A to induce T cell activation. We have now derived, by gene transfection, Chinese hamster ovary cell lines that express the I-Ad molecule, either alone or in context with mB7. We have analyzed these transfectants for their capacity to present Ag to murine CD4+ T lymphocytes. I-Ad/mB7-double transfectants were able to stimulate mixed lymphocyte reactions and to present peptide Ag to specific T cells. Chinese hamster ovary cells that expressed only the I-Ad molecule were not able to stimulate T cell proliferation in these systems. Thus, the mB7 protein is a sufficient costimulatory molecule for the physiologic, Ag-dependent/MHC-restricted activation of murine CD4+ T cells. Stimulation of T cell bulk cultures resulted predominantly in the production of IL-2 and not of IL-4. The costimulatory activity of mB7 is not, however, restricted to the IL-2-secreting subset. We have identified one IL-4-secreting T cell clone, CDC35, which is responsive to mB7 triggering. Finally, we present experiments that suggest that mB7 and peptide/MHC complexes need to be expressed on the same cell for optimal induction of T cell activation.

Animals↗
PubMed1992

Expression and function of the murine B7 antigen, the major costimulatory molecule expressed by peritoneal exudate cells.

The murine B7 (mB7) protein is a potent costimulatory molecule for the T-cell receptor (TCR)-mediated activation of murine CD4+ T cells. We have previously shown that stable mB7-transfected Chinese hamster ovary (CHO) cells but not vector-transfected controls synergize with either anti-CD3 monoclonal antibody-induced or concanavalin A-induced T-cell activation, resulting ultimately in lymphokine production and proliferation. We now have generated a hamster anti-mB7 monoclonal antibody. This reagent recognizes a protein with an apparent molecular mass of 50-60 kDa. The mB7 antigen is expressed on activated B cells and on peritoneal exudate cells (PECs). Antibody blocking experiments demonstrate that mB7 is the major costimulatory molecule expressed by PECs for the activation of murine CD4+ T cells. This suggests an important role for mB7 during immune-cell interactions. We have also surveyed a panel of murine cell lines capable of providing costimulatory activity. Our results indicate that mB7 is the major costimulatory molecule on some but not all cell lines and that there may be additional molecules besides mB7 that can costimulate the activation of murine CD4+ T cells.

Animals↗
PubMed1991

Prophylaxis of bacterial infections with ciprofloxacin in patients undergoing bone marrow transplantation.

Twenty-six oncology patients, 25 of whom received bone marrow transplants, were enrolled in a prospective, randomized, double-blinded, placebo-controlled trial assessing the efficacy of ciprofloxacin, 750 mg p.o. b.i.d., for preventing bacterial infections during prolonged neutropenia. Treatment was begun within 48 hr of initiation of chemotherapy and continued until the absolute granulocyte count recovered to greater than or equal to 500/microliters, or until the onset of fever (greater than or equal to 38.3 degrees C). Seven evaluable subjects received ciprofloxacin, and 11 received placebo. Risk factors for infection were comparable in both groups. Fever occurred in all study subjects, but onset was delayed in ciprofloxacin recipients (median = 6 days after the fall of the absolute granulocyte count to less than or equal to 500/microliters vs. 3 days for placebo recipients, P = 0.01). No clinically or microbiologically documented infections occurred in ciprofloxacin recipients vs. 10 infections in placebo recipients (5 bacteremias, 4 skin/soft tissue infections, 1 urinary tract infection, P = 0.0003). Ciprofloxacin recipients required fewer days of therapeutic antimicrobials (median: 28 antibiotic-days vs. 49, P0.02). The bioavailability of ciprofloxacin appeared comparable to that found in previously published studies of normal volunteers and patients not receiving chemotherapy. Adverse effects and colonization by ciprofloxacin-resistant microorganisms were monitored, but the sample sizes were too small to permit meaningful conclusions about these safety parameters. Ciprofloxacin appears to be effective for preventing bacterial infections in neutropenic patients. Additional trials are needed to establish the optimal dose of ciprofloxacin and to compare its safety and efficacy with those of currently used prophylactic regimens.

Adult↗
PubMed1990

Hepatic venoocclusive disease in autologous bone marrow transplantation of solid tumors and lymphomas.

Retrospective review of 291 solid tumor and lymphoma patients undergoing autologous bone marrow transplantation (BMT) was performed to determine the influence of pretransplant characteristics and preparative regimen to the development of hepatic venoocclusive disease (VOD). Twelve patients (4.1%) developed a clinical syndrome of right upper quadrant (RUQ) tenderness or hepatomegaly, jaundice, and ascites, with or without encephalopathy, within 40 days of marrow reinfusion. Evidence of metastatic liver disease was the only pretransplant characteristic predictive for VOD (P = .0002). Sex, age, histology, hepatitis B serology, and elevated liver function tests were not predictive. No individual preparative agent had a significant effect on the development of VOD. However, a single 2-hour infusion of carmustine (BCNU) (greater than or equal to 450 mg/m2) led to an increased incidence of VOD when compared with the same dose administered in a fractionated schedule (P = .0258) when given with two other chemotherapeutic agents. Seven of eight autopsy specimens confirmed the clinical diagnosis of VOD. The four patients in whom clinical VOD resolved had lower median peak bilirubins (7.3 v 15.9 mg/dL), lower median peak creatinines (2.1 v 4.1 mg/dL), and relatively quick engraftment of neutrophils (mean, 18.7 days). One of the four patients in whom VOD resolved had other grade 4 (life-threatening) toxicities in contrast to eight of eight who succumbed. In summary, VOD is an uncommon complication in autotransplantation of solid tumors and lymphomas. Our data suggest caution in selecting patients with known metastatic liver disease and consideration of a fractionated BCNU schedule especially in combination with other alkylating agents.

Adult↗
PubMed1989

Immunophenotypic profile of CNS lymphoma: a review of eighteen cases.

The cell surface antigenic phenotype of 18 cases of central nervous system (CNS) large-cell lymphoma (14 primary, four secondary) was examined by an immunoperoxidase technique using antibodies that identify B cell restricted and associated antigens. All cases were shown to be of B cell origin by virtue of the expression of monotypic immunoglobulin (Ig) (16 IgM, two IgG) and the pan B cell antigen B1 (CD20). A panel of monoclonal antibodies directed against B cell restricted and associated activation antigens including B5, Blast-1, Blast-2 (CD23), BB1, interleukin 2 receptor (IL2R, CD25), T9 (transferrin receptor) and TNK-TAR (4F2) was used on 12 of the cases. The majority expressed T9 and TNK-TAR. Blast-1 was expressed by less than half the cases and Blast-2 and B5 by one of 12 cases each. This is in contrast to 10 non-CNS diffuse large cell lymphomas where B5 and Blast-1 were present on all cases. This study confirms previous observations that primary CNS large cell lymphomas are of B cell derivation. Moreover, the differences in expression of B cell activation antigens on CNS large cell lymphomas as compared to non-CNS lymphomas raise the possibility that a subset of neoplastic B cells may have unique tropism for the CNS.

B-Lymphocytes↗
PubMed1988

Autologous bone marrow transplantation in the treatment of malignant lymphoma and Hodgkin's disease.

High-dose chemotherapy, both with and without radiotherapy, was pioneered in the treatment of acute leukemia in relapse with allogeneic transplantation, exploiting the steep dose-response curve characteristic of some hematologic neoplasms. Extension to the malignant lymphomas was strengthened by early success in Burkitt's lymphoma and in syngeneic transplantation for lymphoma. The optimal regimen (BACT [carmustine, cytarabine, cyclophosphamide, 6-thioguanine]) and setting are still under investigation for the various grades of lymphomas. The early published experience demonstrated a low ultimate "cure" rate when transplantation was performed in advanced, bulky, and refractory disease. A survey of published reports up to 1986 showed only 16 of 112 long-term, disease-free survivors when autologous bone marrow transplantation (ABMT) was performed in refractory relapse as opposed to 33 of 53 for patients transplanted in second or subsequent remission or in first partial remission. Refractoriness to conventional-dose chemotherapy (no response or progressive disease) cannot be salvaged in the majority of cases. Bone marrow involvement complicates the use of ABMT and may require in vitro elimination with monoclonal antibodies/complement or cytotoxic chemicals. The Dana-Farber Cancer Institute experience shows that the former in vitro treatment does not inhibit bone marrow grafting. When selection criteria for ABMT are applied in drug-sensitive relapse, 50% to 60% long-term, disease-free survival may be expected. Definition of poor prognostic factors in large cell lymphoma may identify patients for ABMT as consolidation of first remission. The issue of marrow purging is unsettled at the present time.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Antigenic heterogeneity among Burkitt's lymphoma cells surviving treatment with monoclonal antibody and complement.

Selective removal of malignant cells from human bone marrow is one requirement for autologous bone marrow transplantation. In earlier studies treatment with multiple monoclonal antibodies and C' was more effective than treatment with individual reagents in eliminating clonogenic Burkitt's lymphoma cells from a twenty-fold excess of human bone marrow. To explore possible mechanisms underlying the additive or synergistic effects observed with multiple reagents, clones of malignant cells that have survived treatment with antibody and C' have now been isolated at limiting dilution. Marked heterogeneity has been observed in binding of different monoclonal antibodies and in resistance to C'-dependent lysis among these different clones. Phenotypic traits were stable for at least two weeks in culture. Clones that survived treatment with the J5 anti-CALLA antibody and C' exhibited a relative decrease in CALLA expression but did not exhibit an increased susceptibility to lysis by anti-CALLA and C'. No selective decrease in gp-26 or B1 was observed in clones treated with J2 or anti-B1. A correlation between CALLA and gp-26 expression was observed in clones treated with J2 and anti-B1, but no clear correlation was observed between antigen expression and susceptibility to C'-dependent lysis. In this model system, escape from C' dependent cytotoxicity does not appear related to the existence of phenotypically stable C' resistant variants within the tumor cell population.

Animals↗
PubMed1986

Elimination of clonogenic tumor cells from human bone marrow using a combination of monoclonal antibody:ricin A chain conjugates.

Effective autologous bone marrow transplantation for leukemia and lymphoma is likely to depend upon the selective removal in vitro of malignant cells from normal human bone marrow precursors. Highly specific cytotoxic conjugates formed by coupling ricin A chain to monoclonal antibodies might prove useful for the selective elimination of malignant cells. Consequently, ricin A chain conjugates have been prepared with several different murine monoclonal antibodies and tested for their ability to eliminate clonogenic Burkitt's lymphoma cells from an excess of human bone marrow. The most active reagents included an antibody:A chain conjugate which bound to the nonpolymorphic chain of the la molecule and another which reacted with the mu heavy chain of cell surface immunoglobulin. Conjugates formed with anti-common acute lymphoblastic leukemia antigen, anti-Mr 26,000 glycoprotein, and anti-B1 were much less active on these Burkitt's cells, contrasting with results of complement-dependent tumor cell lysis. Tumor cell kill was partially inhibited by the addition of greater than 2 X 10(6) human bone marrow cells/ml but could be potentiated by increasing the concentration of conjugate or by the addition of 10 mM ammonium chloride. In the presence of ammonium chloride, at least 4 logs of clonogenic tumor cells could be eliminated within 24 h from a 20-fold excess of bone marrow using 10(-7) M ricin A chain linked to one or two different antibodies. Similar treatment of normal human bone marrow temporarily inhibited granulocyte-macrophage colony-forming units (cell) formation but did not compromise establishment of continuous bone marrow cultures. The degree of selective elimination of tumor cells with A chain antibody conjugates was comparable to that achieved with 4-hydroperoxycyclophosphamide or with multiple monoclonal antibodies and complement.

Ammonium Chloride↗