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R A Reisfeld

Publications and source records attributed to R A Reisfeld.

300 records · Page 17Linked to original sources
PubMedDate not supplied

Effects of granulocytes on human neuroblastoma cells measured by chemiluminescence and chromium-51 release assay.

We investigated whether polymorphonuclear leukocytes (PMN) are able to kill human neuroblastoma cells either directly or if coated with antibody MAb 14.18 that recognizes ganglioside GD2 present on the cell surface of most neuroblastoma cells. Neuroblastoma cells could not be destroyed directly, whereas in the antibody-dependent reaction (ADCC-reaction) they were easily eliminated. In order to answer the question whether reactive oxygen intermediates are involved in this process, chemiluminescence measurements were performed. Compared to the signals that could be measured using opsonized zymosan as stimulus, only weak CL-signals could be registered during the ADCC reaction. Pretreatment of PMN with granulocyte-macrophage colony stimulating factor (GM-CSF) enhanced the CL-signals, catalase and SOD reduced it; however, cell killing was only slightly influenced in the presence of catalase and superoxide dismutase. These data suggested that reactive oxygen compounds do not play a prominent role in the killing process. Definitive evidence for this suggestion could be obtained using PMN from a patient with chronic granulomatous disease (CGD): MAb 14.18 coated neuroblastoma cells could be killed effectively, but no CL-signal could be registered, either in the ADCC-reaction or using opsonized zymosan as stimulus.

Catalase↗
PubMedDate not supplied

Receptor for complement components and xenogeneic erythrocytes on human T- and B-lymphoid cells.

Biological and molecular properties of receptors specific for human T- and B-lymphoid cells are discussed. Sensitive simple and reproducible methods to enumerate B- and T-lymphocytes are described: their possible application in clinical immunology is indicated. A new method to obtain enriched populations of human T- and B-lymphocytes from peripheral blood is described. This method appears to be suitable to investigate the properties of antigens specific for B- and T-lymphoid cells.

Antibody Formation↗
PubMedDate not supplied

Antibody conjugates with morpholinodoxorubicin and acid-cleavable linkers.

Antibody-morpholinodoxorubicin conjugates were prepared for targeted immunotherapy of human melanoma. Spacer molecules that differ in hydrolytic stability were employed between the C-13 of the drug and amino residue of lysine on the monoclonal antibody. Antibody-drug conjugates were made with five structurally different morpholinodoxorubicin derivatives including oxime, phenylhydrazone, (sulfonylphenyl)hydrazone, and acylhydrazone moieties. Hydrolytic stability of the antibody conjugates directly correlated with their in vitro cytotoxicity against melanoma cells. Derivatives or conjugates with the greatest hydrolytic stability showed the least cytotoxicity.

Antibodies, Monoclonal↗
PubMedDate not supplied

Recombinant immunocytokines targeting the mouse transferrin receptor: construction and biological activities.

Localized cytokine therapies with recombinant monoclonal antibody-cytokine fusion proteins, designated immunocytokines, have become of increasing interest for tumor immunotherapy, since they direct immunomodulatory cytokines into the tumor microenvironment. To investigate their mechanisms of action in a variety of syngeneic tumor models, recombinant mouse cytokines IL2 and GM-CSF were engineered as fusion proteins to the carboxyl terminus of a chimeric rat/mouse antitransferrin receptor antibody, ch17217 and expressed in stable-transfected Chinese hamster ovary cells. The recombinant immunocytokines were readily purified by affinity chromatography and their binding characteristics were identical to those shown for the ch17217 antibody. The IL2 immunocytokine had an activity similar to recombinant mouse IL2, whereas the GM-CSF immunocytokine had enhanced cytokine activity relative to recombinant mouse GM-CSF. The clearance rates of ch17217 and the GM-CSF and IL2 immunocytokines were relatively similar with elimination phases (t1/2alpha) of 1.8 h and distribution phases (t1/2beta) of 83, 88, and 91 h, respectively. Both immunocytokines demonstrated effective antitumor activity by suppressing the growth of hepatic metastases of mouse neuroblastoma and pulmonary metastases of mouse colon carcinoma in syngeneic A/J and BALB/c mice, respectively. These results indicate that biologically effective IL2 and GM-CSF immunocytokines combine the targeting ability of an antitransferrin receptor monoclonal antibody with the immunomodulatory functions of each cytokine. Because of the universal expression of the transferrin receptor on mouse tumor cell lines, these constructs should prove useful to determine their efficacy in a wide variety of syngeneic mouse tumor models and to perform detailed studies of their modes of action.

Animals↗
PubMedDate not supplied

Targeting of T lymphocytes to melanoma cells through chimeric anti-GD3 immunoglobulin T-cell receptors.

Immunoglobulin T-cell receptors (IgTCRs) combine the specificity of antibodies with the potency of cellular killing by grafting antibody recognition domains onto TCR signaling chains. IgTCR-modified T cells are thus redirected to kill tumor cells based on their expression of intact antigen on cell surfaces, bypassing the normal mechanism of activation through TCR-peptide-major histocompatibility complex (MHC) recognition. Melanoma is one of the most immunoresponsive of human cancers and has served as a prototype for the development of a number of immunotherapies. The target antigen for this study is the ganglioside GD3, which is highly expressed on metastatic melanoma with only minor immunologic cross-reaction with normal tissues. To determine an optimal configuration for therapy, four combinations of IgTCRs were prepared and studied: sFv-epsilon, sFv-zeta, Fab-epsilon, Fab-zeta. These were expressed on the surface of human T cells by retroviral transduction. IgTCR successfully redirected T-cell effectors in an MHC-unrestricted manner, in this case against a non-T-dependent antigen, with specific binding, activation, and cytotoxicity against GD3+ melanoma cells. Soluble GD3 in concentrations up to 100 microg/ml did not interfere with recognition and binding of membrane-bound antigen. Based on the outcomes of these structural and functional tests, the sFv-zeta construct was selected for clinical development. These results demonstrate key features that emphasize the potential of anti-GD3 IgTCR-modified autologous T cells for melanoma therapies.

Animals↗
PubMedDate not supplied

[The role of interferons in neuroblastoma. 2: Immunomodulatory effects].

The role of Interferon-gamma (IFN-gamma) in the immunotherapy of neuroblastoma was investigated. In vitro experiments showed that IFN-gamma augments the cytotoxicity of Natural Killer (NK) cells and of interleukin 2 (IL-2)-activated NK (LAK) cells against neuroblastoma target cells. Incubation of the neuroblastoma cells with IFN-gamma resulted in an increased susceptibility of these target cells to NK and LAK cells. Additionally, the IFN-gamma-treated neuroblastoma cells showed an increased susceptibility to the antibody-dependent cellular cytotoxicity (ADCC). In patients who have been treated with continuous infusions of IL-2, IL-2-induced secretion of IFN-gamma was detected by measuring the elevation of the 2-5 A synthetase activity in peripheral mononuclear cells or the 2-5 A oligoadenylates in the serum, although IFN-gamma itself was not detectable. From these results we conclude that IFN-gamma may play an important role in the immunotherapy of neuroblastoma in combination with IL-2 and/or with monoclonal antibodies.

Antibody-Dependent Cell Cytotoxicity↗
PubMedDate not supplied

Critical evaluation of bispecific antibodies as targeting agents for boron neutron capture therapy of brain tumors.

Boron neutron capture therapy (BNCT) is based on the nuclear capture reaction that occurs when 10B, a stable isotope, is irradiated with low energy neutrons to produce high linear energy transfer (LET) alpha particles and recoiling 7Li nuclei. In order for BNCT to be successful in treating cancer, approximately 10(9) boron atoms must be delivered per tumor cell to sustain a lethal 10B, (n,a) 7Li capture reaction. In the present study, we have produced and characterized a bispecific antibody (BsAbB8), which was reactive with both human glioma and melanoma cell lines, as well as with a variety of polyhedral borane anions (PBA). The affinity constants (KA) of BsAb-B8 with D-54 MG and M21 cells were 3.49 and 2.57 x 10(8) M-1, respectively, which were almost identical to those of the parental mAb 9.2.27 with these cell lines. In vivo tumor localizing properties were studied in nude mice bearing subcutaneous xenografts of the D-54 MG glioma. Following intravenous injection of 131I-labeled BsAb-B8, 3.4 +/- 0.2% of the injected dose/g was detected in the tumor at 24 hours, and then slowly declined to 2.0 +/- 0.4% at 96 hours compared to 1.34 +/- 0.07% and 0.03 +/- 0.01%, respectively, for normal mouse IgG. Based on the assumption that all the tumor cell antigenic receptor sites could be saturated, the following calculations have been carried out. The maximum concentration of BsAb-B8 that could be delivered to 1 g of D-54 MG glioma cells would be 99.6 micrograms, which could bind 71.7 ng of a PBA. However, since at least 500 x more boron would be required per gram of tumor to sustain a lethal 10B (n,a) 7Li capture reaction, a macromolecule containing -10(3)-10(4) boron atoms rather than a low molecular weight PBA would be required to deliver this amount. Such boron containing macromolecules have been synthesized by us, and future studies should provide information on the feasibility of using them in combination with BsAb-B8 to deliver the requisite amount of 10B.

Animals↗
PubMedDate not supplied

Tumor cell invasion through matrigel is regulated by activated matrix metalloproteinase-2.

We tested the hypothesis that there is a correlation between tumor cell efficiency in activation of matrix metalloproteinase-2 (MMP-2) and invasion through basement membrane-like Matrigel barriers. To generate cells capable of MMP-2 activation, we stably transfected three human tumor cell lines, HT-1080 fibrosarcoma, MCF7 breast carcinoma, and U251.3 glioma with cDNA encoding the full length human membrane-type matrix metalloproteinase-1. Our results show a bimodal correlation between the extent of MMP-2 activation and Matrigel invasion by tumor cells. Cell transfectants characterized by a partial activation of MMP-2 were the most invasive while those with an extensive conversion of MMP-2 proenzyme into enzymatically active forms were the least efficient in invading Matrigel. Modulation of MMP-2 activation by exogenous TIMP-2 reverted the rate of Matrigel invasion by cell transfectants to control levels. We conclude that the regulation of activated MMP-2 in the tumor cells, microenvironment may be critical in facilitating tumor cell invasiveness.

Collagen↗