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Biomedical subjects

R A Reisfeld

Publications and source records attributed to R A Reisfeld.

At least 73 records · Page 4Linked to original sources
PubMed1996

Eradication of human hepatic and pulmonary melanoma metastases in SCID mice by antibody-interleukin 2 fusion proteins.

Antibody-cytokine fusion proteins combine the unique targeting ability of antibodies with the multifunctional activity of cytokines. Here, we demonstrate the therapeutic efficacy of such constructs for the treatment of hepatic and pulmonary metastases of different melanoma cell lines. Two antibody-interleukin 2 (IL-2) fusion proteins, ch225-IL2 and ch14.18-IL2, constructed by fusion of a synthetic sequence coding for human IL-2 to the carboxyl end of the Cgamma1 gene of the corresponding antibodies, were tested for their therapeutic efficacy against xenografted human melanoma in vivo. Tumor-specific fusion proteins completely inhibited the growth of hepatic and pulmonary metastases in C.B-17 scid/scid mice previously reconstituted with human lymphokine-activated killer cells, whereas treatment with combinations of the corresponding antibodies plus recombinant IL-2 only reduced the tumor load. Even when treatment with fusion proteins was delayed up to 8 days after inoculation of tumor cells, it still resulted in complete eradication of micrometastases that were established at that time point. Selection of tumor cell lines expressing or lacking the targeted antigen of the administered fusion protein proved the specificity of the observed antitumor effect. Biodistribution analysis demonstrated that the tumor-specific fusion protein accumulated not only in subcutaneous tumors but also in lungs and livers affected with micrometastases. Survival times of animals treated with the fusion protein were more than doubled as compared to those treated with the combination of the corresponding antibody plus IL-2. Our data demonstrate that an immunotherapeutic approach using cytokines targeted by antibodies to tumor sites has potent effects against disseminated human melanoma.

Animals↗
PubMed1996

Eradication of established hepatic human neuroblastoma metastases in mice with severe combined immunodeficiency by antibody-targeted interleukin-2.

A major problem in the treatment of solid tumors is the eradication of established, disseminated metastases. Here we describe an effective treatment for established experimental hepatic metastases of human neuroblastoma in C. B.-17 scid/scid mice. This was accomplished with an antibody-cytokine fusion protein, combining the unique targeting ability of antibodies with the multifunctional activity of cytokines. An anti-(ganglioside GD2) antibody (ch14.18) fusion protein with interleukin-2 (ch14.18-IL2), constructed by fusion of a synthetic sequence coding for human interleukin-2 (IL-2) to the carboxyl end of the C-gamma1 gene of chl4.18, was tested for its therapeutic efficacy against xenografted human neuroblastoma in vivo. The ch14.18-IL2 fusion protein markedly inhibited growth of established hepatic metastases in SCID (severe combined immunodeficiency) mice previously reconstituted with human lymphokine-activated killer cells. Animals treated with ch14.18-IL2 showed an absence of macroscopic liver metastasis. In contrast, treatment with combinations of ch14.18 and recombinant IL2 at dose levels equivalent to the fusion protein only reduced the tumour load. Survival times of SCID mice treated with the fusion protein were more than double that of control animals. These results demonstrate that an immunotherapeutic approach using a cytokine targeted by an antibody to tumor sites is highly effective in eradicating the growth of established tumor metastases.

Animals↗
PubMed1996

Human neural cell adhesion molecule L1 and rat homologue NILE are ligands for integrin alpha v beta 3.

Integrin alpha v beta 3 is distinct in its capacity to recognize the sequence Arg-Gly-Asp (RGD) in many extra-cellular matrix (ECM) components. Here, we demonstrate that in addition to the recognition of ECM components, alpha v beta 3 can interact with the neural cell adhesion molecule L1-CAM; a member of the immunoglobulin superfamily (IgSF). M21 melanoma cells displayed significant Ca(++)-dependent adhesion and spreading on immunopurified rat L1 (NILE). This adhesion was found to be dependent on the expression of the alpha v-integrin subunit and could be significantly inhibited by an antibody to the alpha v beta 3 heterodimer. M21 cells also displayed some alpha v beta 3-dependent adhesion and spreading on immunopurified human L1. Ligation between this ligand and alpha v beta 3 was also observed to promote significant haptotactic cell migration. To map the site of alpha v beta 3 ligation we used recombinant L1 fragments comprising the entire extracellular domain of human L1. Significant alpha v beta 3-dependent adhesion and spreading was evident on a L1 fragment containing Ig-like domains 4, 5, and 6. Importantly, mutation of an RGD sequence present in the sixth Ig-like domain of L1 abrogated M21 cell adhesion. We conclude that alpha v beta 3-dependent recognition of human L1 is dependent on ligation of this RGD site. Despite high levels of L1 expression the M21 melanoma cells did not display significant adhesion via a homophilic L1-L1 interaction. These data suggest that M21 melanoma cells recognize and adhere to L1 through a mechanism that is primarily heterophilic and integrin dependent. Finally, we present evidence that melanoma cells can shed and deposit L1 in occluding ECM. In this regard, alpha v beta 3 may recognize L1 in a cell-cell or cell-substrate interaction.

Amino Acid Sequence↗
PubMed1996

Systemic interleukin-2 modulates the anti-idiotypic response to chimeric anti-GD2 antibody in patients with melanoma.

The induction of human antimouse antibodies (HAMA) and human anti-idiotypic (anti-Id) responses in cancer patients receiving therapeutic monoclonal antibody (mAb) may limit the effectiveness of the administered mAb. This report evaluates the influence of systemic interleukin-2 (IL-2) on the anti-Id response to anti-disialoganglioside (anti-GD2) antibody given as treatment for patients with melanoma. Twenty-eight patients with melanoma received combined immunotherapy with anti-GD2 antibody and IL-2 at 1.5 x 10(6) U/m2/day given 4 days/week. The anti-GD2 antibody [murine 14.G2a mAb; dose levels of 2-5 mg/m2/day (4 patients); or human-mouse chimeric 14.18 (ch14.18) antibody; dose levels of 2-10 mg/m2/day (24 patients)] was scheduled to be given for 5 days either before, during, or after initial systemic IL-2 treatment. All four patients who received murine 14.G2a developed HAMA anti-isotype antibodies (660-1,000 ng/ml) as well as measurable anti-Id antibodies. All three patients who received initial treatment with ch14.18 alone developed a strong anti-Id antibody response after IL-2 was started 1 week later. The serum level of anti-Id antibody decreased during subsequent ch14.18 infusions, suggesting that the anti-Id antibody may be binding the administered ch14.18. In contrast, measurable anti-Id antibody was detected in only 3 of 14 patients who received IL-2 before, during, and after initial ch14.18 administration. Two of four patients receiving systemic IL-2 before and during initial ch14.18 infusions, and two of three patients receiving systemic IL-2 concurrent with initial ch14.18 infusions developed anti-Id antibodies. These data suggest that the anti-Id response to chimeric anti-GD2 antibody is influenced by the timing of systemic IL-2 in relation to antibody administration and can be suppressed by systemic treatment with IL-2 given before, during, and after the antibody administration.

Adjuvants, Immunologic↗
PubMed1996

Lymphocyte-mediated alopecia in C57BL/6 mice following successful immunotherapy for melanoma.

Successful immunotherapy of established B16 melanoma metastases in C57BL/6 mice can be achieved by antibody-targeted interleukin-2 administration. This therapeutic effect is accompanied in approximately 20% of the animals by induction of a population of lymphocytes that migrates to and substantially disrupts the cytoarchitecture of the skin, which results in progressive alopecia. The histologic changes associated with the hair loss, i.e., peri-, and intrafollicular inflammatory infiltrates consisting of both activated CD4+ and CD8+ T cells, as well as expression of major histocompatibility complex class I antigens on subinfundibular follicle epithelium, are similar to those observed in human alopecia areata. Furthermore, the alopecic phenotype can be transmitted horizontally by passive transfer of lymphocytes from treated animals to naïve mice. Since lymphocytes from treated animals either lacking or displaying signs of alopecia are able to transmit these phenotypic changes to a similar percentage of naïve animals, the initiation of alopecia seems to be dependent on the coincidence of at least two different events: the presence of specific lymphocyte populations as well as specific features of the skin disclosing a target for these cells.

Alopecia↗
PubMed1996

Activation of human effector cells by a tumor reactive recombinant anti-ganglioside GD2 interleukin-2 fusion protein (ch14.18-IL2).

Cytotoxic effector cells interact with target cells through various mechanisms. CTLs use the antigen-specific T cell receptor, whereas Fc receptor-positive natural killer cells use this receptor to interact with antibody-coated target cells. We evaluated the tumor-binding and lymphocyte-activating capability of a recombinant fusion protein consisting of a tumor-selective human/mouse chimeric anti-ganglioside GD2 antibody (ch14.18) and recombinant human interleukin-2 (IL2) (ch14.18-IL2). This fusion protein bound specifically to GD2-positive melanoma and neuroblastoma tumor cell lines, and its IL2 component stimulated in vitro proliferation of an IL2-dependent cell line, as well as peripheral blood mononuclear cells, in healthy control individuals and in cancer patients receiving continuous infusion of IL2. The IL2 presented by the fusion protein, when bound to tumor cells, induced proliferation of IL2-responsive cells as well as a comparable amount of soluble IL2 did. This suggests that localization of IL2 at the site of contact between tumor and effector cells is an effective way of presenting this cytokine to IL2-responsive cells. The ch14.18-IL2 fusion protein also mediated antibody-dependent cellular cytotoxicity with Fc receptor-positive effector cells to an extent similar to ch14.18. These results, together with those of previous studies documenting antitumor efficacy against human tumor xenografts in SCID mice and GD2-positive murine tumors in immunocompetent syngeneic mice, suggest that the ch14.18-IL2 fusion protein should be tested in Phase I and II trials in patients with GD2-positive tumors.

Animals↗
PubMed1995

DNA loops induced by cooperative binding of transcriptional activator proteins and preinitiation complexes.

DNA conformational changes are essential for the assembly of multiprotein complexes that contact several DNA sequence elements. An approach based on atomic force microscopy was chosen to visualize specific protein-DNA interactions occurring on eukaryotic class II nuclear gene promoters. Here we report that binding of the transcription regulatory protein Jun to linearized plasmid DNA containing the consensus AP-1 binding site upstream of a class II gene promoter leads to bending of the DNA template. This binding of Jun was found to be essential for the formation of preinitiation complexes (PICs). The cooperative binding of Jun and PIC led to looping of DNA at the protein binding sites. These loops were not seen in the absence of either PICs, Jun, or the AP-1 binding site, suggesting a direct interaction between DNA-bound Jun homodimers and proteins bound to the core promoter. This direct visualization of functional transcriptional complexes confirms the theoretical predictions for the mode of gene regulation by trans-activating proteins.

Binding Sites↗
PubMed1995

Therapeutic efficacy of a doxorubicin immunoconjugate in a preclinical model of spontaneous metastatic human melanoma.

Doxorubicin (DOX) was conjugated to a monoclonal antibody (mAb 425) directed against the human epidermal growth factor receptor. The immunoreactivity of these conjugates, with an average of six to eight molecules of DOX per antibody, was largely conserved, and their in vitro cytotoxicity against metastatic human melanoma cells (M24 met) was improved over that of free DOX. An evaluation of the therapeutic efficacy of mAb 425-DOX indicated that this immunoconjugate suppressed the growth of primary and secondary M24 met tumors in mice with severe combined immunodeficiency and prolonged the life span of these animals, whereas an equivalent dose of free DOX was ineffective. Conjugation of DOX to an irrelevant mAb also increased its antitumor effect over that of equivalent amounts of free drug but to a lesser extent than that achieved by the mAb 425-DOX conjugate. These results demonstrate targeted delivery and striking antitumor activity of DOX immunoconjugates in a preclinical model of spontaneous, metastatic human melanoma that was insensitive to free DOX.

Animals↗
PubMed1995

Negative transcriptional regulation in anergic T cells.

Anergy is a mechanism of T-lymphocyte tolerance induced by antigen-receptor stimulation in the absence of costimulation, whereby T cells exhibit a defect in antigen-induced transcription of the interleukin 2 (IL-2) gene. Here we present evidence for a mechanism of negative IL-2 gene regulation in anergic T cells. High amounts of binding activity to the negative regulatory element A (NRE-A) of the IL-2 promotor were detected in nuclear extracts from human T cells shortly after induction of anergy. Rapid induction of this nuclear complex is blocked by cyclosporin A and is found to be independent of protein synthesis. Plasmid DNAs, containing either the human phorbol 12-myristate 13-acetate-responsive element (PRE) or both NRE-A and PRE, were used as template for in vitro transcription assays in the presence of T-cell nuclear extracts. Under these conditions nuclear extracts from both anergic and rested T-cell clones, after crosslinking of CD3 and CD28, induced transcription of plasmids containing only PRE. However, when plasmids containing NRE-A and PRE were used, transcription was only induced by nuclear extracts from rested but not anergic T cells. These findings suggest the functional relevance of transcriptional repression of the IL-2 gene in anergic T cells.

Antigens, CD↗
PubMed1995

Superantigen-staphylococcal-enterotoxin-A-dependent and antibody-targeted lysis of GD2-positive neuroblastoma cells.

Superantigens such as the staphylococcal enterotoxin A (SEA) are among the most potent T cell activators known. They bind to major histocompatibility complex (MHC) class II molecules and interact with T cells depending on their T cell receptor (TCR) V beta expression. Superantigens also induce a variety of cytokines and trigger a direct cytotoxic effect against MHC-class-II-positive target cells. In order to extend superantigen-dependent cell-mediated cytotoxicity (SDCC) to MHC-class-II-negative neuroblastoma cells, SEA was linked to the anti-ganglioside GD2 human/mouse chimeric monoclonal antibody (mAb) ch14.18. Ganglioside GD2 is expressed on most tumours of neuroectodermal origin but is expressed to a lesser extent on normal tissues. The linkage of ch14.18 to SEA was achieved either with a protein-A-SEA fusion protein or by chemical coupling. Both constructs induced T-cell-mediated cytotoxicity towards GD2-positive neuroblastoma cells in an effector-to-target(E:T)-ratio- and dose-dependent manner in vitro. To reduce the MHC class II affinity of SEA, a point mutation was introduced in the SEA gene (SEAm9) that resulted in 1000-fold less T cell killing of MHC-class-II-expressing cells as compared to native SEA. However, a protein-A-SEAm9 fusion protein mediated cytotoxicity similar to that of protein-A-SEA on ch14.18-coated, MHC-class-II-negative neuroblastoma cells. Taken together, these findings suggest that superantigen-dependent and monoclonal-antibody-targeted lysis may be a potent novel approach for neuroblastoma therapy.

Antibodies, Monoclonal↗
PubMed1995

Pharmacokinetics of anti-ganglioside GD2 mAb 14G2a in a phase I trial in pediatric cancer patients.

A phase I trial of a murine anti-ganglioside (GD2) monoclonal antibody (mAb) 14G2a was conducted in 14 neuroblastoma patients and 1 osteosarcoma patient to assess its safety, toxicity and pharmacokinetics in pediatric patients. The pharmacokinetics of mAb 14G2a were biphasic with a t alpha 1/2 of 2.8 +/- 2.8 h and a t beta 1/2 of 18.3 +/- 11.8 h. In general, t beta 1/2 was dose-dependent with a level of significance of P = 0.036, and it reached a plateau at doses of 250 mg/m2 or more. Overall the peak serum levels were dose-dependent at P < 0.001. However, they demonstrated an abrupt increase between doses of 100 mg/m2 and 250 mg/m2. The latter two suggest a saturable mechanism for mAb elimination. In addition, peak serum concentrations were observed earlier at higher mAb doses, which indicates the achievement of a steady state. The t beta 1/2 of mAb 14G2a in children appears to be shorter than in adults. Furthermore, 2 patients demonstrated a considerable decrease in t beta 1/2 following retreatment with 14G2a. This was paralleled by high human anti-(mouse Ig) antibody levels. This study represents the first comprehensive analysis of murine mAb pharmacokinetics in children and will be useful in the future design of mAb therapy.

Adolescent↗
PubMed1995

A phase I study of human/mouse chimeric antiganglioside GD2 antibody ch14.18 in patients with neuroblastoma.

9 patients with stage IV neuroblastoma were treated with 19 courses of human/mouse chimeric monoclonal antiganglioside GD2 antibody ch14.18 at dose levels of 30, 40 and 50 mg/m2/day for 5 days per course. The maximum tolerated dose (MTD) per injection was 50 mg/m2/day. 7 patients received more than one course of treatment, and none revealed any human anti-mouse antibody (HAMA) response. Clinical side-effects of patients treated with ch14.18 were abdominal and joint pains, pruritus and urticaria. One patient presented with a transient pupillatonia, while 2 others showed a unilateral atrophy of the optical nerve that was probably attributable to prior therapies. A complete remission was seen in 2 patients, partial remission in 2 patients, a minor response in 1 patient and stable disease in 1 patient. 3 patients showed tumour progression. Thus, our results indicate that treatment with chimeric MAb ch14.18 can elicit some complete and partial tumour responses in neuroblastoma patients.

3-Iodobenzylguanidine↗
PubMed1995

Bispecific antibodies as targeting agents for boron neutron capture therapy of brain tumors.

Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when boron-10, a stable isotope, is irradiated with low energy (< or = 0.025 eV) or thermal neutrons to yield alpha particles and recoiling lithium-7 nuclei. A major requirement for the success of BNCT is the selective delivery of a sufficient number of boron atoms (approximately 10(9)) to individual cancer cells to sustain a lethal 10B (n, alpha) 7Li capture reaction. A panel of BsAb reactive with polyhedral borane anions (PBA) and a tumor-associated chondroitin sulfate proteoglycan has been produced. All of these BsAb showed strong reactivity with a panel of human glioblastoma and melanoma cell lines, as demonstrated by indirect membrane immunofluorescence. Two of them (H6 and B8) also reacted with cells that had been exposed to PBA (Na2B10H10 and Na2B12H11SH) and a boronated starburst dendrimer, which contained approximately 250-400 B atoms per molecule. The affinity constant (Ka) of BsAb-B8 was 2.57 x 10(8) M-1 on M21 human melanoma cell and 3.49 x 10(8) M-1 on A172 glioblastoma cells, which were almost identical to those of the parental monoclonal antibody (mAb) 9.2.27 on the same cell lines (2.62 x 10(8) M-1). Since our BsAb recognize both human glioblastoma and melanoma-associated antigens, as well as PBA, they potentially could be used to target 10B to these tumors for BNCT.

Animals↗
PubMed1994

Integrin alpha v beta 3 antagonists promote tumor regression by inducing apoptosis of angiogenic blood vessels.

A single intravascular injection of a cyclic peptide or monoclonal antibody antagonist of integrin alpha v beta 3 disrupts ongoing angiogenesis on the chick chorioallantoic membrane (CAM). This leads to the rapid regression of histologically distinct human tumors transplanted onto the CAM. Induction of angiogenesis by a tumor or cytokine promotes vascular cell entry into the cell cycle and expression of integrin alpha v beta 3. After angiogenesis is initiated, antagonists of this integrin induce apoptosis of the proliferative angiogenic vascular cells, leaving preexisting quiescent blood vessels unaffected. We demonstrate therefore that ligation of integrin alpha v beta 3 is required for the survival and maturation of newly forming blood vessels, an event essential for the proliferation of tumors.

Allantois↗