Optimal Saturated Neuropilin-1 Expression in Normal Tissue Maximizes Tumor Exposure to Anti-Neuropilin-1 Monoclonal Antibody

2020 ◽  
Vol 19 (18) ◽  
pp. 2269-2275 ◽  
Author(s):  
Chao Ma ◽  
Xiaofeng Dou ◽  
Jianghua Yan ◽  
Shengyu Wang ◽  
Rongshui Yang ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Normal Tissue ◽  
Optimal Dose ◽  
Tumor Xenograft ◽  
Dependent Manner ◽  
Tumor Uptake ◽  
Biodistribution Studies ◽  
Neuropilin 1 ◽  
Unlabeled Antibody

Background: As involved in tumor angiogenesis, Neuropilin Receptor type-1 (NRP-1) serves as an attractive target for cancer molecular imaging and therapy. Widespread expression of NRP-1 in normal tissues may affect anti-NRP-1 antibody tumor uptake. Objective: To assess a novel anti-NRP-1 monoclonal antibody A6-11-26 biodistribution in NRP-1 positive tumor xenograft models to understand the relationships between dose, normal tissue uptake and tumor uptake. Methods: The A6-11-26 was radiolabeled with 131I and the mice bearing U87MG xenografts were then administered with 131I-labelled A6-11-26 along with 0, 2.5, 5, and 10mg·kg-1 unlabelled antibody A6-11-26. Biodistribution and SPECT/CT imaging were evaluated. Results: 131I-A6-11-26 was synthesized successfully by hybridoma within 60min. It showed that most of 131IA6- 11-26 were in the plasma and serum (98.5 ± 0.16 and 88.9 ± 5.84, respectively), whereas, less in blood cells. For in vivo biodistribution studies, after only injection of 131I-A6-11-26, high levels of radioactivity were observed in the liver, moderate level in lungs. However, liver and lungs radioactivity uptakes could be competitively blocked by an increasing amount of unlabeled antibody A6-11-26, which can increase tumor radioactivity levels, but not in a dose-dependent manner. A dose between 10 and 20mg·kg-1 of unlabeled antibody A6-11-26 may be the optimal dose that maximized tumor exposure. Conclusion: Widespread expression of NRP-1 in normal tissue may affect the distribution of A6-11-26 to tumor tissue. An appropriate antibody A6-11-26 dose would be required to saturate normal tissue antigenic sinks to achieve acceptable tumor exposure.

scholarly journals In Vivo Biodistribution and Lifetime Analysis of Cy5.5-Conjugated Rituximab in Mice Bearing Lymphoid Tumor Xenograft Using Time-Domain Near-Infrared Optical Imaging

2008 ◽  
Vol 7 (6) ◽  
pp. 7290.2008.00028 ◽  
Author(s):  
Stefania Biffi ◽  
Chiara Garrovo ◽  
Paolo Macor ◽  
Claudio Tripodo ◽  
Sonia Zorzet ◽  
...  
Keyword(s):  
B Cell ◽  
Optical Imaging ◽  
Time Domain ◽  
Near Infrared ◽  
Ex Vivo ◽  
Tumor Xenograft ◽  
Tumor Uptake ◽  
Biodistribution Studies

Rituximab is a chimeric monoclonal antibody directed against human CD20 antigen, which is expressed on B-cell lymphocytes and on the majority of B-cell lymphoid malignancies. Herein we report the conjugate of rituximab with the near-infrared (NIR) fluorophore Cy5.5 (RI-Cy5.5) as a tool for in vitro, in vivo, and ex vivo NIR time-domain (TD) optical imaging. In vitro, RI-Cy5.5 retained biologic activity and led to elevated cell-associated fluorescence on tumor cells. In vivo, TD optical imaging analysis of RI-Cy5.5 injected into lymphoma-bearing mice revealed a slow tumor uptake and a specific long-lasting persistence of the probe within the tumor. Biodistribution studies after intraperitoneal and endovenous administration were undertaken to evaluate differences in the tumor uptake. RI-Cy5.5 concentration in the organs after intraperitoneal injection was not as high as after endovenous injection. Ex vivo analysis of biologic tissues and organs by both TD optical imaging and immunohistochemistry confirmed the probe distribution, as demonstrated by imaging experiment in vivo, showing that RI-Cy5.5 selectively accumulated in the tumor tissue and major excretion organs. In summary, the study indicates that NIR TD optical imaging is a powerful tool for rituximab-targeting investigation, furthering understanding of its administration outcome in lymphoma treatment.

scholarly journals Design of PSMA ligands with modifications at the inhibitor part: an approach to reduce the salivary gland uptake of radiolabeled PSMA inhibitors?

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Veronika Barbara Felber ◽  
Manuel Amando Valentin ◽  
Hans-Jürgen Wester
Keyword(s):  
Salivary Gland ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
In Vivo Studies ◽  
Tumor Xenograft ◽  
Tumor Uptake ◽  
Lncap Cells ◽  
High Affinity

Abstract Aim To investigate whether modifications of prostate-specific membrane antigen (PSMA)-targeted radiolabeled urea-based inhibitors could reduce salivary gland uptake and thus improve tumor-to-salivary gland ratios, several analogs of a high affinity PSMA ligand were synthesized and evaluated in in vitro and in vivo studies. Methods Binding motifs were synthesized ‘on-resin’ or, when not practicable, in solution. Peptide chain elongations were performed according to optimized standard protocols via solid-phase peptide synthesis. In vitro experiments were performed using PSMA+ LNCaP cells. In vivo studies as well as μSPECT/CT scans were conducted with male LNCaP tumor xenograft-bearing CB17-SCID mice. Results PSMA ligands with A) modifications within the central Zn2+-binding unit, B) proinhibitor motifs and C) substituents & bioisosteres of the P1′-γ-carboxylic acid were synthesized and evaluated. Modifications within the central Zn2+-binding unit of PSMA-10 (Glu-urea-Glu) provided three compounds. Thereof, only natLu-carbamate I (natLu-3) exhibited high affinity (IC50 = 7.1 ± 0.7 nM), but low tumor uptake (5.31 ± 0.94% ID/g, 1 h p.i. and 1.20 ± 0.55% ID/g, 24 h p.i.). All proinhibitor motif-based ligands (three in total) exhibited low binding affinities (> 1 μM), no notable internalization and very low tumor uptake (< 0.50% ID/g). In addition, four compounds with P1′-ɣ-carboxylate substituents were developed and evaluated. Thereof, only tetrazole derivative natLu-11 revealed high affinity (IC50 = 16.4 ± 3.8 nM), but also this inhibitor showed low tumor uptake (3.40 ± 0.63% ID/g, 1 h p.i. and 0.68 ± 0.16% ID/g, 24 h p.i.). Salivary gland uptake in mice remained at an equally low level for all compounds (between 0.02 ± 0.00% ID/g and 0.09 ± 0.03% ID/g), wherefore apparent tumor-to-submandibular gland and tumor-to-parotid gland ratios for the modified peptides were distinctly lower (factor 8–45) than for [177Lu]Lu-PSMA-10 at 24 h p.i. Conclusions The investigated compounds could not compete with the in vivo characteristics of the EuE-based PSMA inhibitor [177Lu]Lu-PSMA-10. Although two derivatives (3 and 11) were found to exhibit high affinities towards LNCaP cells, tumor uptake at 24 h p.i. was considerably low, while uptake in salivary glands remained unaffected. Optimization of the established animal model should be envisaged to enable a clear identification of PSMA-targeting radioligands with improved tumor-to-salivary gland ratios in future studies.

Preliminary Study on Radioimmunodiagnosis of Experimental Tumor Models Using Technetium-99m-Labeled Anti-C-erbB-2 Monoclonal Antibody

2002 ◽  
Vol 88 (6) ◽  
pp. 507-512 ◽  
Author(s):  
Ananthanarayanan Meenakshi ◽  
Rayala Suresh Kumar ◽  
Venkatraman Ganesh ◽  
Nallathambi Siva Kumar
Keyword(s):  
Monoclonal Antibody ◽  
Early Stage ◽  
Survival Rates ◽  
Premalignant Lesions ◽  
Breast Carcinoma Cell Line ◽  
Tumor Models ◽  
Primary Tumors ◽  
Biodistribution Studies ◽  
Preliminary Study

Aims and background One of the great challenges of oncology is to improve methods for early tumor detection. Diagnosis of premalignant lesions and early stage primary tumors is crucial for the success of cancer therapy and increased survival rates. Growth factor receptors localized to the cell membrane play a vital role in cancer. Monoclonal antibodies labeled with radioisotopes have been used extensively for radioimmunodiagnosis and radioimmunotherapy of various malignancies. A preliminary study on immunoscintigraphy was carried out on animal tumor models using 99mTc-labeled monoclonal antibody CIBCgp185 generated against the C-erbB-2 oncoprotein with a view to develop technologies for in vivo radioimmunodetection and localization of human breast cancer. Methods Mammary tumor xenografts induced using BT474 cells, a breast carcinoma cell line showing overexpression of C-erbB-2, were used for immunoscintigraphic studies. Results Scintigrams showed high radiolabel uptake by the tumor tissue of the mice belonging to the experimental group, whereas in control animals no radiolabel uptake was visualized. Biodistribution studies correlated well with scintiscans. Conclusions The results indicate the potential application of this monoclonal antibody for in vivo diagnosis of occult malignancies of tumors with overexpression of C-erbB-2.

scholarly journals Synthesis and evaluation of radiolabeled, folic acid-PEG conjugated, amino silane coated magnetic nanoparticles in tumor bearing Balb/C mice

Nukleonika ◽  
2015 ◽  
Vol 60 (3) ◽  
pp. 497-502 ◽  
Author(s):  
Javad Razjouyan ◽  
Hamidreza Zolata ◽  
Omid Khayat ◽  
Fereidoun Nowshiravan ◽  
Nami Shadanpour ◽  
...  
Keyword(s):  
Folic Acid ◽  
Folate Receptor ◽  
Superparamagnetic Iron Oxide ◽  
Fibroblast Cell ◽  
Mouse Fibroblast ◽  
Tumor Uptake ◽  
Mri Imaging ◽  
Tumor Bearing ◽  
Biodistribution Studies

Abstract To design a potent agent for positron emission tomography/magnetic resonance imaging (PET/MRI) imaging and targeted magnetic hyperthermia-radioisotope cancer therapy radiolabeled surface modified superparamagnetic iron oxide nanoparticles (SPIONs) were used as nanocarriers. Folic acid was conjugated for increasing selective cellular binding and internalization through receptor-mediated endocytosis. SPIONs were synthesized by the thermal decomposition of tris (acetylacetonato) iron (III) to achieve narrow and uniform nanoparticles. To increase the biocompatibility of SPIONs, they were coated with (3-aminopropyl) triethoxysilane (APTES), and then conjugated with synthesized folic acid-polyethylene glycol (FA-PEG) through amine group of (3-aminopropyl) triethoxysilane. Finally, the particles were labeled with 64Cu (t1/2 = 12.7 h) using 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid mono (N-hydroxy succinimide ester) DOTA-NHS chelator. After the characterization of SPIONs, their cellular internalization was evaluated in folate receptor (FR) overexpressing KB (established from a HeLa cell contamination) and mouse fibroblast cell (MFB) lines. Eventually, active and passive targeting effects of complex were assessed in KB tumor-bearing Balb/C mice through biodistribution studies. Synthesized bare SPIONs had low toxicity effect on healthy cells, but surface modification increased their biocompatibility. Moreover, KB cells viability was reduced when using folate conjugated SPIONs due to FR-mediated endocytosis, while having little effect on healthy cells (MFB). Moreover, this radiotracer had tolerable in vivo characteristics and tumor uptake. In the receptor blocked case, tumor uptake was decreased, indicating FR-specific uptake in tumor tissue while enhanced permeability and retention effect was major mechanism for tumor uptake.

scholarly journals Anti-Nosemosis Activity of Aster scaber and Artemisia dubia Aqueous Extracts

2018 ◽  
Vol 62 (1) ◽  
pp. 27-38
Author(s):  
Jae Kwon Lee ◽  
Jeong Hwa Kim ◽  
Mina Jo ◽  
Balamurugan Rangachari ◽  
Jin Kyu Park
Keyword(s):  
Optimal Dose ◽  
Dependent Manner ◽  
Aqueous Extracts ◽  
Active Components ◽  
Aqueous Fraction ◽  
Ethanol Extracts ◽  
Artemisia Dubia ◽  
Dose Dependent

Abstract In our previous study, we demonstrated that the ethanol extracts of Artemisia dubia (A. dubia) and Aster scaber (A. scaber) have anti-nosemosis activity. In our present study, we intend to establish the anti-nosemosis activity of aqueous, ethyl acetate (EA), and butanol (BuOH) extracts of A. dubia and A. scaber. In order to determine the optimal dose, we performed both in vitro and in vivo toxicity for all the extracts and also carried out anti-nosemosis experiments. Although all of the extracts (aqueous, EA, and BuOH) showed in vitro and in vivo anti-nosemosis activity in a dose-dependent manner, the aqueous extracts of A. dubia and A. scaber showed more potent anti-nosemosis activity than the EA and BuOH extracts. Moreover, an aqueous extract of A. dubia + A. scaber demonstrated stronger anti-nosemosis activity compared with the aqueous extracts of either A. dubia or A. scaber alone. Although the main ingredients in A. dubia and A. scaber remain unclear, our results suggest that the active components of A. dubia and A. scaber could dissolve in the aqueous fraction.

scholarly journals First Preclinical Report of the Efficacy and PD Results of KHK2823, a Non-Fucosylated Fully Human Monoclonal Antibody Against IL-3Rα

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1349-1349 ◽  
Author(s):  
Tadakazu Akiyama ◽  
Shin-ichiro Takayanagi ◽  
Yoshimi Maekawa ◽  
Kohta Miyawaki ◽  
Fumiaki Jinnouchi ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Antitumor Activity ◽  
Tumor Growth ◽  
Rat Model ◽  
Research Funding ◽  
Tumor Xenograft ◽  
Cynomolgus Monkeys ◽  
Nude Rat

Abstract Human interleukin-3 receptor alpha (IL-3Ra, CD123), which promotes the proliferation and differentiation of hematopoietic cells, is highly expressed in myeloid malignancies, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). We newly generated KHK2823, a non-fucosylated fully human IgG1 monoclonal antibody against human IL-3Ra, by utilizing the POTELLIGENT® technology. Here, we describe the in vitro and in vivo preclinical efficacy and safety of KHK2823, as well as its pharmacodynamic (PD) profile. At first, we explored that KHK2823 bound to various hematological malignant cells and leukemic stem cells. The cells from AML and MDS bone marrows were found to be bound by KHK2823. A significant part of bone marrow cells derived from B-cell acute lymphoblastic leukemia (B-ALL) patients was also bound by KHK2823. KHK2823 bound to soluble human IL-3Ra protein with a sub-nanomolar dissociation constant (KD), and recognized CD34+ CD38+ (leukemic blast) and/or CD34+ CD38- (leukemic stem cell) cells in patients with AML/MDS, as well as AML cell lines, thereby obtaining a high antibody-dependent cellular cytotoxic activity without complement-dependent cytotoxicity. Interestingly, KHK2823 did not interfere with the binding of IL-3 to IL-3R. The lack of a receptor-ligand interaction may conserve the IL-3 signal, which plays an important role in normal hematopoiesis. In a tumor model xenografting the human AML cell line MOLM-13 on nude rats, KHK2823 significantly suppressed the tumor growth at doses of 0.1 and 1 mg/kg (Figure 1). The PD and toxicity profiles of KHK2823 were assessed in cynomolgus monkeys administered at doses ranging from 0.1 to 100 mg/kg by i.v. infusion, once weekly for 4 weeks. KHK2823 was generally well tolerated in monkeys, even at 100 mg/kg. The number of IL-3Ra-positive cells in the peripheral blood of cynomolgus monkeys decreased in all groups receiving KHK2823, which suggest KHK2823 could exert its depletion activity of IL-3Ra-positive cells in human (Figure 2). Currently, the safety and tolerability of KHK2823 is being investigated in patients with AML or MDS in a Phase 1 study (NCT02181699, https://clinicaltrials.gov/ct2/show/NCT02181699). This is the first non-randomized, open-label, dose escalation clinical study to investigate the safety, PK, immunogenicity and PD of repeated doses of KHK2823. In summary, KHK2823 was confirmed to bind to AML, MDS and B-ALL cells as the IL-3Ra in accordance with other publications. KHK2823 was also found to eliminate AML cells in vitro and also suppressed the AML tumor growth in the in vivo model. In addition, the number of IL-3Ra-positive cells in cynomolgus monkeys decreased following i.v. infusion of 0.1mg/kg KHK2823 with a tolerable safety profile, even at a dose of 100 mg/kg. Taken together, KHK2823 may therefore be a promising anti-IL-3Ra therapeutic drug for the treatment of AML. Figure 1. Antitumor activity of KHK2823 in a tumor xenograft nude rat model Figure 1. Antitumor activity of KHK2823 in a tumor xenograft nude rat model Figure 2. PD profile of KHK2823 in cynomolgus monkeys Figure 2. PD profile of KHK2823 in cynomolgus monkeys Disclosures Akiyama: Kyowa Hakko Kirin Co., Ltd.: Employment. Takayanagi:Kyowa Hakko Kirin Co., Ltd.: Employment. Maekawa:Kyowa Hakko Kirin Co., Ltd.: Employment. Shimabe:Kyowa Hakko Kirin Co., Ltd.: Employment. Nishikawa:Kyowa Hakko Kirin Co., Ltd.: Employment. Yamawaki:Kyowa Hakko Kirin Co., Ltd: Employment. Iijima:Kyowa Hakko Kirin Co., Ltd: Employment. Hiura:Kyowa Hakko Kirin Co., Ltd.: Employment. Takahashi:Kyowa Hakko Kirin Co., Ltd.: Employment. Akashi:Asahi Kasei: Research Funding, Speakers Bureau; Chugai: Research Funding, Speakers Bureau; Bristol-Myers Squibb: Research Funding, Speakers Bureau; Novartis Pharma K.K.: Consultancy, Research Funding, Speakers Bureau; Kyowa Hakko Kirin Co., Ltd.: Consultancy, Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Shionogi: Research Funding, Speakers Bureau; Astellas: Research Funding, Speakers Bureau. Tawara:Kyowa Hakko Kirin Co., Ltd: Employment.

A Fibrin Specific Monoclonal Antibody which Interferes with the Fibrinolytic Effect of Tissue Plasminogen Activator

1988 ◽  
Vol 59 (03) ◽  
pp. 426-431 ◽  
Author(s):  
P E Gargan ◽  
V A Ploplis ◽  
J D Scheu
Keyword(s):  
Monoclonal Antibody ◽  
Cell Line ◽  
Specific Antibody ◽  
Myeloma Cell ◽  
Dependent Manner ◽  
Mouse Myeloma Cell Line ◽  
Release Assay ◽  
Dose Dependent ◽  
Mouse Myeloma

SummaryMonoclonal antibodies to human fibrin have been prepared from stable hybridomas, obtained by fusion of a mouse myeloma cell line (NS-1) and spleen cells of Balb/c mice immunized with a suspension of human fibrin. One cell line, DG1, producing a monoclonal antibody of the IgG1 κ subclass, reacted specifically with human fibrin (KD = 1.2 nM). Western blotting analysis indicates that DG1 crossreacts with the fibrin fragment D-dimer. Using both a chromogenic and an 125I-fibrin release assay it was illustrated that in the presence of the fibrin specific antibody the t-PA mediated generation of plasmin was significantly inhibited.An animal model system, developed to monitor thrombosis and induced reactive fibrinolysis, was used to investigate the interference of plasminogen activation, by the antibody, in vivo.This fibrin specific antibody prolonged the onset of reactive fibrinolysis in a dose dependent manner.

Effects of novel heparin-derived compounds on tumor uptake of chemotherapeutics and chemoresponse

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 2537-2537 ◽  
Author(s):  
P. Phillips ◽  
M. Yalcin ◽  
H. Cui ◽  
H. H. Abdel-Nabi ◽  
M. Sajjad ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Human Lung ◽  
Lung Tumor ◽  
Xenograft Model ◽  
Chemotherapeutic Agents ◽  
Tumor Xenograft ◽  
Tumor Uptake ◽  
Human Lung Tumor ◽  
Biodistribution Studies ◽  
Human Lung Carcinoma

2537 Thrombotic complications are the second most common cause of mortality in cancer patients and fibrin deposition in the tumor microenvironment might play a key role in tumor progression and inference with tumor chemotherapeutic uptake. Treatments that target these processes may result in improved uptake of chemotherapeutic agents and subsequent inhibition of tumor growth and metastasis. Tissue Factor (TF) is frequently associated with aggressive behavior and poor outcome in tumors. We have previously demonstrated potent anti-tumor efficacy for various mechanisms that interfere with TF/VIIa. The purpose of this study was to investigate the effects of low molecular weight heparins (LMWH) and sulfated non-anticoagulant LMWH (S-NACH) on tumor chemotherapeutic uptake. Studies: (1) Nude mice xenograft A549 human lung carcinoma: LMWH or S-NACH at 10 mg/kg S.C. daily effectively limited tumor growth. (2) LCC6 human lung tumor xenograft model: Paclitaxel alone or in combination with Tinzaparin or S-NACH on tumor re-growth after discontinuation of treatment: Paclitaxel + S-NACH treatment showed significant (P<0.01) tumor growth suppression and improved survival when compared to Paclitaxel. (3) Biodistribution studies: animals were injected with LMWH S.C. daily for 5 days (10 mg/kg) then injected i.v. with [124-I]-Paclitaxel. LMWH increased [124-I]-Paclitaxel uptake into LCC6 tumors with tumor: muscle ratios several fold greater than that of [124-I]-Paclitaxel alone at 24 hrs post injection. This is a highly significant result in the light of the fact that the FDA criterion for a clinically meaningful effect is a 15% increase in uptake. (4) HPLC studies of tumor uptake of Doxorubicin (DOX in mice treated with 10 mg/kg of LMWH or S-NACH for 10 days followed by Doxorubicin (2.5 mg/kg). Both LMWH and S-NACH significantly (P<0.01) increased the uptake of chemotherapeutic agent DOX in MCF7 DOX resistant tumors by 1.5–2 folds but not in heart or lung tissues, confirming the findings obtained with another agent [124-I]-Paclitaxel. Conclusions: LMWH or S-NACH increased chemotherapeutics uptake and hence chemoresponse. Protocols utilizing adjuvant or neo-adjuvant therapy with LMWH or S-NACH could lead to increase tumor chemo responsiveness and overcoming tumor chemo resistance. No significant financial relationships to disclose.

Abstract 630: Novel Chimeric Anti-proteoglycan Antibody Inhibits Arterial Retention of Proatherogenic Lipoproteins in a Rat Model of Insulin Resistance

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Yosdel Soto ◽  
Rabban Mangat ◽  
Ana M Vázquez ◽  
Spencer D Proctor
Keyword(s):  
Insulin Resistance ◽  
Monoclonal Antibody ◽  
Ex Vivo ◽  
Dependent Manner ◽  
Insulin Resistant ◽  
Remnant Lipoproteins ◽  
Preferential Binding ◽  
Carotid Vessels

Background: The response-to-retention hypothesis for atherosclerosis describes subendothelial retention of apolipoprotein B-containing lipoproteins mediated by proteoglycans (PG). Further we know that diabetes is also associated with both increased circulating chylomicron remnants and remodeling of proatherogenic PGs. We have recently reported antiatherogenic properties of a novel chimeric monoclonal antibody (chP3R99) that recognizes PG sulfated molecules. Hypothesis: chP3R99 monoclonal antibody may interfere with the interaction of atherogenic lipoproteins with arterial sulfated PGs during insulin resistance. Methods and Results: chP3R99 antibody recognized sulfated glycosaminoglycans by ELISA showing a preferential binding to chondroitin sulfate. Also, chP3R99 blocked the interaction of proatherogenic lipoproteins with this glycosaminoglycan in vitro in a dose-dependent manner and its intravenous injection into healthy Sprague-Dawly rats (n=6, 1 mg/animal) inhibited LDL (4 mg/kg; intraperitoneally) aortic retention. To further assess this property in an insulin resistant condition, carotid arteries from control and JCR:LA-cp rats (n=4) were perfused ex vivo with apoB48 containing remnant lipoproteins (prepared via rabbit hepatectomy procedure), with or without Cy3-LDL (150 μg/mL) for 20 minutes. Confocal microscopy analysis revealed an increased arterial retention of both remnants (3.6 fold) and LDL (2.8 fold) in carotid vessels from insulin resistant rats relative to control. However, chP3R99 pre-perfusion resulted in decreased retention of remnants (-30%) and LDL (-60%) associated arterial cholesterol. Data suggests that the chP399 antibody may interfere with the arterial attachment of both remnants and LDL in vivo, but with differential efficacy. Conclusions: Relative to LDL, remnant lipoproteins had preferential accumulation in arterial vessels from insulin resistant rats ex vivo , which could then be inhibited by acute pre-exposure to the chP3R99 antibody. These in vivo data support the concept for an innovative approach to target the retention of proatherogenic lipoproteins in a pre-clinical setting.

In Vitro Activity of a Novel Fully Human Anti-CD40 Antibody CHIR-12.12 in Chronic Lymphocytic Leukemia: Blockade of CD40 Activation and Induction of ADCC.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2504-2504 ◽  
Author(s):  
Xia Tong ◽  
Georgios V. Georgakis ◽  
Long Li ◽  
O’Brien Susan ◽  
Younes Anas ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Cell Death ◽  
Chronic Lymphocytic Leukemia ◽  
Cell Line ◽  
Blood Donors ◽  
Lymphocytic Leukemia ◽  
Dependent Manner ◽  
Dose Dependent

Abstract B-cell chronic lymphocytic leukemia (CLL) is characterized by in vivo accumulation of long-lived CD5+ B cells. However when cultured in vitro CLL cells die quickly by apoptosis. Protection from apoptosis in vivo is believed to result from supply of survival signals provided by cells in the microenvironment. We and others have previously reported that CLL cells express CD40 receptor, and that CD40 stimulation of CLL cells may rescue CLL cells from spontaneous and drug-induced apoptosis in vitro. These observations suggested that blocking CD40-CD40L pathway might deprive CLL cells from survival signals and induce apoptosis. To test this hypothesis, we have generated a fully human anti-CD40 blocking monoclonal antibody in XenoMousemice (Abgenix, Inc.). The antibody CHIR-12.12 was first evaluated for its effect on normal human lymphocytes. Lymphocytes from all 10 healthy blood donors did not proliferate in response to CHIR-12.12 at any concentration tested (0.0001 mg/ml to 10 mg/ml range). In contrast, activating CD40 on normal B-lymphocytes by CD40L induced their proliferation in vitro. Importantly, CHIR-12.12 inhibited CD40L- induced proliferation in a dose dependent manner with an average IC50 of 51 ± 26 pM (n=10 blood donors). The antagonistic activity of CHIR-12.12 was then tested in primary CLL samples from 9 patients. CHIR-12.12 alone did not induce CLL cell proliferation. In contrast, primary CLL cells incubated with CD40L, either resisted spontaneous cell death or proliferated. This effect was reversed by co-incubation with CHIR-12.12 antibody, restoring CLL cell death (n=9). CHIR-12.12 was then examined for its ability to lyse CLL cell line EHEB by antibody dependent cell mediated cytotoxicity (ADCC). Freshly isolated human NK cells from normal volunteer blood donors were used as effector cells. CHIR-12.12 showed lysis activity in a dose dependent manner and produced maximum lysis levels at 0.1 mg/ml. When compared with rituximab, CHIR-12.12 mediated greater maximum specific lysis (27.2 % Vs 16.2 %, p= 0.007). The greater ADCC by CHIR-12.12 was not due to higher density of CD40 molecules on CLL cell line compared to CD20 molecules. The CLL target cells expressed 509053 ±13560 CD20 molecules compared to 48416 ± 584 CD40 molecules. Collectively, these preclinical data suggest that CHIR-12.12 monoclonal antibody may have a therapeutic role in patients with CLL.

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