Characterization of neutralizing antibodies reacting with the 213-224 amino-acid segment of human galectin-9

Caractérisation d'anticorps neutralisants réagissant avec le segment des acides aminés 213-224 de la galectine-9 humaine

Claire C. Lhuillier (1) , Clément Barjon (1) , Valentin Baloche (1) , Toshiro Niki (2) , Aurore Gelin (1) , Rami Mustapha (3) , Laetitia Claër (4) , Sylviane Hoos (5) , Yoichi Chiba (2) , Masaki Ueno (2) , Mitsuomi Hirashima (2) , Ming Wei (6) , Olivier Moralès (3) , Bertrand Raynal (5) , Nadira Delhem (3) , Olivier Dellis (7) , Pierre Busson (1)

1 UMR8126 - Signalisation, noyaux et innovations en cancérologie
2 Kagawa University [Japan]
3 IBLI - Institut de biologie de Lille - IBL
4 H-Immune Therapeutics [Paris]
5 Biophysique Moléculaire (Plate-forme)
6 Cellvax
7 ICPH - Intéractions cellulaires et physiopathologie hépatique (Orsay, Essonne) UMRS 1174

Extra-cellular galectin-9 (gal-9) is an immuno-modulatory protein with predominant immuno-suppressive effects. Inappropriate production of gal-9 has been reported in several human malignancies and viral diseases like nasopharyngeal, pancreatic and renal carcinomas, metastatic melanomas and chronic active viral hepatitis. Therefore therapeutic antibodies neutralizing extra-cellular gal-9 are expected to contribute to immune restoration in these pathological conditions. Two novel monoclonal antibodies targeting gal-9-Gal-Nab 1 and 2-have been produced and characterized in this study. We report a protective effect of Gal-Nab1 and Gal-Nab2 on the apoptotic cell death induced by gal-9 in primary T cells. In addition, they inhibit late phenotypic changes observed in peripheral T cells that survive gal-9-induced apoptosis. Gal-Nab1 and Gal-Nab2 bind nearly identical, overlapping linear epi-topes contained in the 213-224 amino-acid segments of gal-9. Nevertheless, they have some distinct functional characteristics suggesting that their three-dimensional epitopes are distinct. These differences are best demonstrated when gal-9 is applied on Jurkat cells where Gal-Nab1 is less efficient than Gal-Nab2 in the prevention of apoptotic cell death. In addition, Gal-Nab1 stimulates non-lethal phosphatidylserine translocation at the plasma membrane and calcium mobilization triggered by gal-9 in these cells. Both Gal-Nab1 and 2 cross-react with murine gal-9. They bind its natural as well as its recombinant form. This cross-species recognition will be an advantage for their assessment in pre-clinical tumor models.

Mots clés: Apoptosis T cells; Enzyme-linked immunoassays; Antibodies; Lactose; Flow cytometry; Antibody isotypes; Cell staining

Domaines: Sciences du Vivant [q-bio]; Biologie cellulaire; Cancer; Immunologie

Claire C. Lhuillier, Clément Barjon, Valentin Baloche, Toshiro Niki, Aurore Gelin, et al.. Characterization of neutralizing antibodies reacting with the 213-224 amino-acid segment of human galectin-9. PLoS ONE, 2018, 13 (9), pp.e0202512. ⟨10.1371/journal.pone.0202512⟩. ⟨hal-02414847⟩