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  • An innovative strategy to identify new targets for delivering antibodies to the brain has led to the exploration of the integrin family.

An innovative strategy to identify new targets for delivering antibodies to the brain has led to the exploration of the integrin family.

PloS one (2022-09-16)
Céline Cegarra, Béatrice Cameron, Catarina Chaves, Tarik Dabdoubi, Tuan-Minh Do, Bruno Genêt, Valérie Roudières, Yi Shi, Patricia Tchepikoff, Dominique Lesuisse
ABSTRACT

Increasing brain exposure of biotherapeutics is key to success in central nervous system disease drug discovery. Accessing the brain parenchyma is especially difficult for large polar molecules such as biotherapeutics and antibodies because of the blood-brain barrier. We investigated a new immunization strategy to identify novel receptors mediating transcytosis across the blood-brain barrier. We immunized mice with primary non-human primate brain microvascular endothelial cells to obtain antibodies. These antibodies were screened for their capacity to bind and to be internalized by primary non-human primate brain microvascular endothelial cells and Human Cerebral Microvascular Endothelial Cell clone D3. They were further evaluated for their transcytosis capabilities in three in vitro blood-brain barrier models. In parallel, their targets were identified by two different methods and their pattern of binding to human tissue was investigated using immunohistochemistry. 12 antibodies with unique sequence and internalization capacities were selected amongst more than six hundred. Aside from one antibody targeting Activated Leukocyte Cell Adhesion Molecule and one targeting Striatin3, most of the other antibodies recognized β1 integrin and its heterodimers. The antibody with the best transcytosis capabilities in all blood-brain barrier in vitro models and with the best binding capacity was an anti-αnβ1 integrin. In comparison, commercial anti-integrin antibodies performed poorly in transcytosis assays, emphasizing the originality of the antibodies derived here. Immunohistochemistry studies showed specific vascular staining on human and non-human primate tissues. This transcytotic behavior has not previously been reported for anti-integrin antibodies. Further studies should be undertaken to validate this new mechanism in vivo and to evaluate its potential in brain delivery.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, protease free, fatty acid free, essentially globulin free, pH 7, ≥98%
Sigma-Aldrich
Anti-Integrin Beta1, clone AIIB2 (Azide Free) Antibody, clone AIIB2, 1 mg/mL, from rat
Sigma-Aldrich
Anti-Integrin Beta1 Antibody, clone 8E3, clone 8E3, from mouse
Sigma-Aldrich
Anti-Integrin β1 Antibody, activated, clone HUTS-4, Azide Free, clone HUTS-4, Chemicon®, from mouse
Sigma-Aldrich
Anti-Integrin β1 Antibody, a.a. 82-87, clone JB1A (a.k.a. J10), ascites fluid, clone JB1A (J10), Chemicon®