Characterization and biodistribution of a mouse/human chimeric antibody directed against pancreatic cancer mucin

Abstract

Background. Nd2 is a murine monoclonal antibody (MoAb) directed against purified mucins of the human pancreatic cancer cell line SW1990. The authors previously reported promising results with Nd2 for immunotargeting pancreatic cancer. However, murine MoAbs induce human anti‐mouse antibodies (HAMAs), a serious problem for clinical use. Mouse/human chimeric antibodies may be less immunogenic and therefore reduce the incidence of HAMAs. In this study, the binding affinity, tumor specificity, biodistribution, and immunoimaging of chimeric Nd2 were evaluated. Methods. The affinity of chimeric Nd2 was evaluated by competition radioimmunoassay and Scatchard analysis using 125I‐chimeric Nd2,125I‐murine Nd2, and SW1990 mucin. Immunoreactivity against pancreatic cancer tissues was examined histochemically bv the avidin‐biotin peroxidase complex method. The biodistribution of the MoAbs was examined in athymic nude mice bearing SW1990 xenografts that were administered intravenous 125I‐labeled chimeric or murine Nd2. 111In‐chimeric Nd2 was injected into the same xenograft models, and scintigrams were obtained on day 3. Results. Affinity analysis and immunohistochemical studies showed that chimeric Nd2 had the same affinity to SW1990 mucin and the same specificity for pancreas cancer tissues as murine Nd2. Intravenous administration of 125I‐chimeric Nd2 resulted in a maximum tumor accumulation of 43% of the initial dose/gram of tumor, which was almost identical to the accumulation of 125I‐murine Nd2. Distinct immunoscintigrams of tumors in nude mice were obtained with 111In‐chimeric Nd2. Conclusion. Chimeric Nd2 may have clinical potential in the radioimmunodetection and immunotherapy of pancreatic cancer. Cancer 1995;75:1545‐53.

Preoperative Clinical Radioimmunodetection of Pancreatic Cancer by 111In‐labeled Chimeric Monoclonal Antibody Nd2

“…But one case of TFP (patient; 13) was false positive in RAID with c-Nd2. While Nd2, in general, shows no reaction to tissues of normal pancreas (including pancreatic ducts, acinar cells and islet cells) and chronic pancreatitis, 5,11) this surgical specimen demonstrated positive reactivity to Nd2 on acinar cells surrounding the branch of the pancreatic duct with epithelial hyperplasia, which is an unusual finding in chronic pancreatitis. Hyperplasia of pancreatic ducts is usually found in cases of mucin-producing pancreatic tumor (particularly intraductal papillary adenoma) and cystadenoma, which have high malignant potential.…”

“…Thus, we prepared mouse /human chimeric Nd2 (c-Nd2), which retains the high affinity and specificity to pancreatic cancer of murine Nd2 (m-Nd2). 10,11) The present study was carried out to investigate the clinical usefulness of c-Nd2 for preoperative diagnosis after labeling with 111 In, and its therapeutic potential for pancreatic cancer.…”

Antibody‐dependent Cytotoxicity Mediated by Chimeric Monoclonal Antibody Nd2 and Experimental Immunotherapy for Pancreatic Cancer

“…In order to reduce the side effects resulting from HAMA production in clinical trials, we produced c-Nd2 and found that its specificity and affinity to pancreatic cancer are similar to those of m-Nd2. 16) Since other investigators have suggested that chimeric antibodies are similar or superior to murine antibodies in ability to mediate ADCC, in this study we examined pancreatic cancer cell cytotoxicity during MLTC with Nd2 in order to determine the extent of induction of ADCC by c-Nd2. Cytotoxicity during MLTC for pancreatic cancer cell lines was increased by incubation with c-Nd2 in an E/T ratio-and dose-dependent fash- To estimate the in vivo effect of ADCC induced by cNd2, we examined inhibition of subcutaneous xenograft tumor growth and determined the survival of orthotopically transplanted nude mice following intraperitoneal injection of c-Nd2.…”

“…The antigen-binding affinities of m-Nd2 and c-Nd2 were investigated by competitive radioimmunoassay and Scatchard analyses as described by Hirayama et al 16) Pancreatic cancer cell line The human pancreatic cancer cell lines RWP-1 (well differentiated adenocarcinoma), Capan-1 (moderately differentiated), SW1990 (well/ moderately differentiated), Capan-2 (moderately differentiated), Panc-1 (poorly differentiated), and MiaPaca-2 (undifferentiated) were cultured in high-glucose Dulbecco's modified Eagle's minimum essential tissue medium (DMEM; Nikken Biomedical Laboratory, Kyoto) supplemented with 10% fetal calf serum (FCS; Gibco, Grand Island, NY), 100 IU/ml penicillin (ICN Biochemicals, Costa Mesa, CA) 100 IU/ml streptomycin (ICN Biochemicals) and sodium pyruvate (ICN Biochemicals). These cells were used as target cells for cytotoxicity assay.…”

“…Chimeric MoAbs have been reported to induce antibody-dependent cell-mediated cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC), and are therefore thought to be more useful clinically for targeting therapy than mouse MoAbs. [12][13][14][15] We have prepared chimeric Nd2 (c-Nd2) which has high affinity and specificity for pancreatic cancer, as exhibited by m-Nd2, 16,17) and have reported its usefulness for clinical radioimmunodetection and radioimmunotherapy. 18,19) In this study, we examined whether c-Nd2 induces in vitro ADCC, and studied the in vivo effect of c-Nd2 mediated by ADCC in subcutaneously xenografted and orthotopically transplanted pancreatic cancer in nude mouse.…”