ABSTRACT
Brain exposure of systemically administered biotherapeutics is highly restricted by the blood-brain barrier (BBB). Here, we report the engineering and characterization of a BBB transport vehicle targeting the CD98 heavy chain (CD98hc or SLC3A2) of heterodimeric amino acid transporters (TVCD98hc). The pharmacokinetic and biodistribution properties of a CD98hc antibody transport vehicle (ATVCD98hc) are assessed in humanized CD98hc knock-in mice and cynomolgus monkeys. Compared to most existing BBB platforms targeting the transferrin receptor, peripherally administered ATVCD98hc demonstrates differentiated brain delivery with markedly slower and more prolonged kinetic properties. Specific biodistribution profiles within the brain parenchyma can be modulated by introducing Fc mutations on ATVCD98hc that impact FcγR engagement, changing the valency of CD98hc binding, and by altering the extent of target engagement with Fabs. Our study establishes TVCD98hc as a modular brain delivery platform with favorable kinetic, biodistribution, and safety properties distinct from previously reported BBB platforms.
Subject(s)
Blood-Brain Barrier , Brain , Animals , Mice , Tissue Distribution , Antibodies , Engineering , Macaca fascicularisABSTRACT
T-cell engagers (TCEs) are a growing class of biotherapeutics being investigated in the clinic for treatment of a variety of hematological and solid tumor indications. However, preclinical evaluation of TCEs in vivo has been mostly limited to xenograft tumor models in human T-cell reconstituted immunodeficient mice, which have a number of limitations. To explore the efficacy of human TCEs in fully immunocompetent hosts, we developed a knock-in mouse model (hCD3E-epi) in which a 5-residue N-terminal fragment of murine CD3-epsilon was replaced with an 11-residue stretch from the human sequence that encodes for a common epitope recognized by anti-human CD3E antibodies in the clinic. T cells from hCD3E-epi mice underwent normal thymic development and could be efficiently activated upon crosslinking of the T-cell receptor with anti-human CD3E antibodies in vitro. Furthermore, a TCE targeting human CD3E and murine CD20 induced robust T-cell redirected killing of murine CD20-positive B cells in ex vivo hCD3E-epi splenocyte cultures, and also depleted nearly 100% of peripheral B cells for up to 7 days following in vivo administration. These results highlight the utility of this novel mouse model for exploring the efficacy of human TCEs in vivo, and suggest a useful tool for evaluating TCEs in combination with immuno-oncology/non-immuno-oncology agents against heme and solid tumor targets in hosts with a fully intact immune system.
Subject(s)
Antibodies, Bispecific , Neoplasms , Animals , Antigens, CD20 , CD3 Complex , Epitopes , Humans , Mice , T-LymphocytesABSTRACT
BACKGROUND: Organ regeneration in mammals is hypothesized to require a functional pool of stem or progenitor cells, but the role of these cells in lung regeneration is unknown. METHODS: Based on the fact that postnatal regeneration of alveolar tissue has been attributed to alveolar epithelial cells, we established a hemorrhagic shock and Lipopolysaccharide (LPS) lung injury model. Using this model, we analyzed the cellular kinetics of lung alveolar epithelial cells. RESULTS: The results showed that alveolar epithelium type 2 cells (AEC2s) are damage resistant during acute lung injury, they might be the main cells involved in lung injury and repair. Then we observed the relationship between the expression of HGF, c-Met following ALI in rat lung and proliferation of AEC2s. The proliferation of AEC2s was inhibited when isolated primary AEC2s were co-cultured with c-Met inhibitor SU11274. Furthermore, the numbers of AEC2s was significantly decreased when ALI rats were administrated with SU11274 in vivo. It provided further evidence that the HGF/c-Met signaling plays a vital role in ALI-induced AEC2s proliferation. CONCLUSIONS: AEC2s are damage resistant during acute lung injury and the HGF/c-Met signaling pathway is of vital importance in the proliferation of AEC2s after ALI.
Subject(s)
Acute Lung Injury/pathology , Cell Proliferation , Epithelial Cells/pathology , Pulmonary Alveoli/pathology , Regeneration , Acute Lung Injury/chemically induced , Acute Lung Injury/metabolism , Acute Lung Injury/physiopathology , Animals , Cell Proliferation/drug effects , Disease Models, Animal , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Hepatocyte Growth Factor/metabolism , Indoles/pharmacology , Kinetics , Lipopolysaccharides , Male , Piperazines/pharmacology , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins c-met/antagonists & inhibitors , Proto-Oncogene Proteins c-met/metabolism , Pulmonary Alveoli/drug effects , Pulmonary Alveoli/metabolism , Pulmonary Alveoli/physiopathology , Rats, Sprague-Dawley , Regeneration/drug effects , Signal Transduction , Sulfonamides/pharmacologyABSTRACT
In recent years, more and more research has shown that the lung is an organ of regenerative potential, with several types of stem/progenitor cells undergoing proliferation and differentiation after lung injury and participating the injury repair process. Mouse lung multipotent stem cells (MLSCs) have extensive self-renewal ability in culture and could differentiate into endothelial and lung epithelial (alveolar epithelial type 1, 2, and Clara) cells in vitro. But the research of MLSCs was limited due to its rarity. In this study, we introduced a novel microfluidic magnetic activated cell sorting system in the isolation of MLSCs. The sorted MLSCs had better viability and purity. They were identified by colony formation efficiency and differentiation ability and they have self-renewal and differentiation capacities, highlighting their stem cell properties.
