摘要:

Lym-1, a monoclonal antibody (MAb) that preferentially targets malignant lymphocytes, has induced therapeutic remissions in patients with advanced non-Hodgkin's lymphoma (NHL) or chronic lymphocytic leukemia (CLL) when labeled with iodine-131 (131I). Based on the strategy of fractionating the total radiation dose, trials were designed to define the safety, toxicity, and efficacy of a series of doses of131I-Lym-l given 2-6 weeks apart. All patients had disease resistant to standard therapy.131I-Lym-l was given after unconjugated Lym1 and the131I dose was escalated in Phase I-II trials. Therapy proved safe. The dose-limiting toxicity was thrombocytopenia. Nonhematological toxicities did not exceed grade 2 except for infrequent instances of grade 3 hypotension. In a low-dose (LD) trial of131I-Lym-l, tumor regression occurred in 25 (83%) of 30 patients and 17 (57%) had durable remissions; 3 of the remissions were complete. In a maximum tolerated dose (MTD) trial of131I-Lym-l, 10 (71%) of 14 entries that received at least two doses of131I-Lym-l therapy and 11 (52%) of 21 total entries had remissions; 7 of the remissions were complete. All 3 entries in the MTD cohort of 100 mCi/m2[3.7 MBq/m2] of body surface area had durable complete remissions. Therapeutic remission and human anti-mouse antibody (HAMA) after Lym-1 therapy were associated with increased survival that was significant in multivariate analyses. Evidence for an Ab3 idiotypic network with an antibody cytotoxic for Raji human lymphoma was found in the only patient examined in detail thus far; this patient was studied because she had a high titer, HAMA and prolonged survival. In conclusion,131I-Lym-l induced durable remissions in patients with chemotherapy-resistant NHL or CLL and was associated with acceptable toxicity. In a subset of the patients, survival was quite prolonged perhaps related to development of Ab3.

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.1

年代:1999

数据来源: MAL

摘要:

Pretargeting techniques have promise for radioimmunotherapy (RIT) in cancer because of the potential for markedly increasing the therapeutic ratio. Human antibody fragments can be retrieved from phage libraries and used to realize this potential. The library can be used to select the genetic material required to generate molecules with binding sites for both radiochelates and tumor antigens. In this study, human anti-chelate scFvs (single-chain fragments) for two metal chelates (Cu-TETA and Y-DOTA) were selected from a large, naive human scFv library. These anti-chelate scFvs were intended to serve as one arm of bispecific pretargeting molecules and to bind radiochelates given subsequently as Cu-67-TETA or Y-90-DOTA. Phage that displayed the anti-chelate scFv were selected by absorption to antibody (Lym-1) bound Cu-TETA or Y-DOTA. Enzyme-linked immunosorbent assays (ELISA) were performed to assess the intensity and specificity of phage binding to the specific chelate. Ninety-six clones demonstrating metal chelate binding seven times greater than to Lym-1 alone were chosen for diversity analysis. BstN I restriction digests were performed on DNA from these clones. Twenty-three and 43 different DNA fingerprint patterns were identified for anti-TETA and antiDOTA clones, respectively. DNA sequencing of 39 anti-TETA clones for 23 different BstN I fingerprint patterns revealed 22 distinct sequences. Eleven of the anti-TETA clones were selected for further study. Five hundred to 1000 γg (100 to 320 γg per liter of culture) of purified scFv was produced from each of the 11 anti-TETA clones. Preliminary studies by BIAcore demonstrated evidence of 25- to 200-nM affinities. Comparable examination of the anti-DOTA clones is in progress. This study provides evidence that human scFv against unique synthetic targets can be readily selected from a large, naive human immunoglobulin phage library. Selections against metal chelated antibodies provided a wealth of scFvs with diverse binding affinities useful for engineering molecules for pretargeting RI

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.13

年代:1999

数据来源: MAL

摘要:

The screening of tumor-derived expression libraries for antigens which are recognized by high titered IgG antibodies present in autologous sera of the cancer patients by SEREX (serological identification of antigens by recombinant expression cloning) allows for the systematic identification of antigens in human cancers. SEREX has led to the definition of a plentitude of new tumor antigens in many different tumor entities. The majority of the antigens are encoded by hitherto unknown genes and can be grouped into different classes of antigens. The abundance of serologically defined human tumor antigens is not only of relevance for tumor biology and serodiagnosis of cancer, but also facilitates the identification of proteins recognized by tumor specific T lymphocytes, thus providing a molecular basis for polyvalent peptide-based and gene-therapeutic vaccine strategies in a wide variety of human neoplasms.

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.23

年代:1999

数据来源: MAL

摘要:

Binding of epidermal growth factor (EGF) to the EGF receptor is known to trigger a number of biological responses in the target cells including EGF receptor phosphorylation and stimulation of DNA synthesis leading to cell proliferation. Agents that bind to the EGF receptors could have a significant role in the therapy of tumors that express increased numbers of receptors by blocking the stimulatory effect of EGF. Different monoclonal antibodies (MAbs) directed to the EGF receptor have been generated that inhibit EGF binding and do not induce activation of the receptor tyrosine kinase. When there is sufficient uptake these antibodies can be used for immunotherapy and, after labeling with an appropriate radionuclide, also for radioimmunotherapy. For evaluation of a ligand as a therapeutic agent, it is necessary to investigate its binding characteristics in tumor cells and experimental tumorsin vivo. Because the effectiveness of the antitumor activity of the MAb is dependent upon the amount of receptors in the tissue and the penetration of the MAb into the tissue, the receptor density, biokinetics, and tumor distribution of the MAb or its fragments were evaluated in different tumor models. The results of the experimental studies with tumor cell spheroids and different xenotransplanted human tumors have shown that the uptake and distribution in the tumor tissue is dependent on the molecular weight of the ligand. The correlation between the uptake of the substances and the receptor density is an indication for a noninvasive scintigraphic characterization of human tumors using radiolabeled compounds with specific binding to the tumor receptor and for selection of an optimal therapeutic regimen or radionuclide targeting of the tumor.

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.29

年代:1999

数据来源: MAL

摘要:

Substantial progress has been made in detecting cell surface or intracytoplasmatic antigens to identify spreaded tumor cells with monoclonal antibodies (MAbs). The 17-1A antigen is already used as a target for specific immunotherapy in colorectal cancer. The purpose of this study was to compare the expression of 17-1A antigen in colorectal tumors versus breast cancers. MAb against the epithelial-specific antigen (ESA) and a routine staining technique were used to detect the 17-1A antigen in 100 cases of colorectal and 111 cases of breast cancer. The antigen expression of each tumor entity was examined by light microscopy on paraffin sections. Thirty six of the formalin-fixed paraffin sections of breast cancer were compared with their correspondending frozen sections. Evaluation was realized by a histological score (grade 0-9) considering the distribution and the staining intensity. We found an antigen expression of 17-1A in colorectal cancer quantified at 7.1 ± 1.8 and at 4.5 ± 2.5 for breast cancer in our score. Comparing paraffin sections and frozen sections in the 36 cases of breast cancer, the score was 5.5 ± 2.3 in the paraffin and 8.1 ± 1.9 in the frozen section group. Our results confirmed the high expression of 17-1A cases of in colorectal carcinoma. Furthermore, 17-1A is expressed in the majority of breast carcinomas, revealing a high difference between paraffin and frozen sections. As a result, a specific immunotherapy with MAbs against 17-1A antigen in minimal residual stages of breast cancer might be conside

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.37

年代:1999

数据来源: MAL

摘要:

In a first clinical trial, 45 patients with advanced ovarian carcinoma and recurrences were treated with the murine monoclonal anti-idiotypic antibody (Ab2) designated ACA125 for active immunotherapy. The monoclonal antibody (MAb) ACA125 mimics a specific epitope of the tumor-associated antigen CA125 expressed by most malignant ovarian tumors. Patients with CA125-positive tumors are immunologically tolerant to CA125, which could be overcome by the use of an anti-idiotypic antibody as a surrogate for the tumor antigen CA125. An immunological response to the anti-idiotype ACA125 in these patients was associated with a statistically significant survival prolongation. Humoral immunity to ACA125 was assessed by induction of anti-anti-idiotypic antibodies (Ab3) directed against CA125. Using flow cytometric detection methods we observe alterations of the intracellular cytokines IFN-γ, IL-2, and IL-4 at the single-cell level during the course of immunization. There was a strong increase of intracellular IFN-γ and IL-2 characteristic for a Th1 cell type immune response after treatment with ACA125. A delayed induction of Th2 type response, which promotes antibody-mediated immunity by B cells, could also be detected. The understanding of the kinetics of Thl and Th2 responses could be important to improve treatment schedules for effective immunotherapy with anti-idiotype vaccine

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.41

年代:1999

数据来源: MAL

摘要:

The monoclonal antibody (MAb) B43.13, binding to the ovarian cancer-associated antigen CA125, has been injected into more than 200 patients with ovarian cancer to detect recurrence of the disease. The follow-up of the patients revealed surprisingly long survival spans for several patients despite high CA125 levels. To investigate the therapeutic effectiveness of OvaRexTMMAb-B43.13 (AltaRex, Edmonton, Canada) under well-controlled conditions, the antibody was tested in a human-PBL-SCID/BG mouse model with CA125 positive human ovarian cancer cells. Mice were reconstituted with human peripheral blood lymphocytes (PBL, normal donors) by intraperitoneal (IP) injection of 2 to 3 x 107PBL/mouse. OvaRexTMMAb-B43.13 was administered at 100 μg/mouse in phosphate buffered saline (PBS), in three different experimental set-ups. An isotype-matched control antibody (MOPC21 or MAb-170) and PBS injection served as controls. The ovarian cancer cell line NIH:OVCAR-NU-3 was injected IP at 1 x 106cells/mouse or subcutaneously (SC) at 4 x 106cells/mouse. Human-PBL-SCID/BG mice were either immunized before injection of tumor cells, along with tumor cells or after small tumors were established (2 weeks after transplantation). Antibody injections were repeated twice in 2-week intervals. Functional and cellular characterization of serum and PBL from these mice demonstrated the successful engraftment of a human immune system in those mice. All three experiments showed that OvaRexTMMAb-B43.13 treatment could (a) delay or prevent development of tumors; (b) reduce the size of small established tumors (SC tumor injection) or suppress ascites formation; (c) delay tumor growth when injected prior to tumor implantation; and (d) prolong the survival of the mice (i.p. tumor injection)

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.47

年代:1999

数据来源: MAL

摘要:

Appreciation of the complementary nature of T-cell- and antibody-based immunotherapy stimulated interest in developing approaches that combine their advantages and minimize their limitations. A recent strategy is based on permanent grafting of cytotoxic T cells with a recombinant chimeric receptor designed for cellular targeting with antibody-like specificity and for cellular activation after binding to antigen. The extracellular moiety of the chimeric receptor consists of an antigen-binding domain derived from an antibody, the intracellular moiety consists of a signalling domain for cellular activation, thus combining the broad specificity of antibody-based and major histocompatibility complex (MHC)-independent recognition with the potent antitumor activity of T cells. By generation of specific T cells against any antigen for which a suitable monoclonal antibody (MAb) exists, the chimeric receptor strategy has the potential to extend the adoptive immunotherapy for a variety of malignant and infectious diseases. However, little is known about the optimized design of this type of receptor. We here discuss our results in grafting T cells with chimeric receptors of various design with regard to efficient cellular activation.

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.57

年代:1999

数据来源: MAL

摘要:

Monoclonal antibodies (MAb) specific for tumor-associated antigens (TAA) can induce an immunological cellular attack of tumor cells by a process termed antibody dependent cellular cytotoxicity (ADCC). Cytokines may augment ADCC by direct activation of immune cells or by enhancement of TAA on tumor cells. Thus, we investigated whether ADCC by MAb 17-1A and BR55-2, which recognize TAA on colorectal tumor cells, can be augmented by 3-day incubation with different concentrations of IL-2, IL-4, IL-6, IL-12, IFN-α, IFNγ, GM-CSF, M-CSF, and TNF-α. ADCC was assessed by a new flowcytometric cytotoxicity assay (Flieger et al. Immunol Methods 1995; 180:1-13) using PKH-2 labeled HT29 cells as targets and PKH-26 labeled peripheral blood mononuclear cells from three healthy volunteers as effector cells. We found three reaction patterns with the cytokines tested: (a) cytokines, which increase ADCC (IL-2, IL-12, IFN-α, and IFN-γ, which represent Th1 cytokines); (b) cytokines with no effect (GM-CSF, M-CSF, and TNF-α); and (c) cytokines, which decrease ADCC (IL-4 and IL-6, which represent Th2 cytokines). Then, we tested cytokines that increase ADCC in combination with the other cytokines. We found that the combinations IL-2/IFN-α, IL-2/IFN-γ, IL-2/IL-12, and IL-12/IFN-α potentiated ADCC. By contrast, IL-4 reduced the IL-2, IL-12, and IFN-α-induced ADCC. Since the Th1 response, cooperation of monocytes and CD4 cells is involved, we plan to elucidate by magnetic cell sorting (MACS) separation techniques, which cells are involved in cytokine-induced ADCC. Our results may be useful for finding combinations of cytokines and MAb for the locoregional treatment of colorect

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.63

年代:1999

数据来源: MAL

摘要:

The ErbB2 receptor tyrosine kinase is often overexpressed in human malignancies and causally involved in transformation. High levels of ErbB2 in tumor cells correlate with an unfavorable prognosis. This makes the ErbB2 receptor an interesting target for tumor therapy, and several strategies have been designed to direct drugs to ErbB2-expressing cells. We established a novel cellular model that allows preclinical evaluation of ErbB2-directed drugs in immunocompetent animals. Renal carcinoma (Renca) cells are an established tumor cell line that origined in Balb/c mice. Upon intravenous transplantation, these cells form pulmonary metastases in Balb/c mice. The transforming genetic lesions in these cells are not fully characterized, but do not seem to involve alterations in ErbB2 gene expression. We transfected Renca cells with the gene encoding the human ErbB2 receptor to provide a target structure for specific drugs and with the bacterial lacZ gene to provide a sensitive means of detection of the tumor cells in the transplanted animals. These genetically modified cells form lung metastasis and can be easily visualized on the surface of lung tissue by staining with an X-gal solution. This allows a quantitative analysis of the number of ErbB2-expressing pulmonary metastasis. We previously used these Renca cells to evaluate the efficacy of an ErbB2-specific tumor toxin on pulmonary métastases in an adjuvant and a palliative treatment setting. In both cases, we achieved a dramatic reduction of disseminated lung lesions. Here we show that even at an advanced stage of metastasis formation, the ErbB2specific toxin is able to efficiently reduce the number of pulmonary tumors

ISSN:0272-457X    

DOI:10.1089/hyb.1999.18.69

年代:1999

数据来源: MAL