hCTLA4-Ig transgene expression in keratocytes modulates rejection of corneal xenografts in a pig to non-human primate anterior lamellar keratoplasty model

Bertrand Vabres (1) , Stéphanie Le Bas-Bernardet (1, 2, 3) , David Riochet (1, 2, 3) , Yan Cherel (4) , David Minault (2, 3) , Jérémy Hervouet (2, 3) , Yvette Ducournau (1) , Anne Moreau (1) , Véronique Daguin (2, 3) , Flora Coulon (2, 3) , Annaïck Pallier (2, 3) , Sophie Brouard (2, 3) , Simon C. Robson (5) , Mark B. Nottle (6) , Peter J. Cowan (7, 8) , Eric Venturi (9) , Pascal Mermillod (10) , Philippe Brachet (11, 3) , Cesare Galli (12, 13) , Irina Lagutina (12, 13) , Roberto Duchi (12, 13) , Jean-Marie Bach (14) , Gilles Blancho (1, 2, 3) , Jean-Paul Soulillou (2, 3) , Bernard Vanhove (1, 2, 3)

1 CHU Nantes - Centre Hospitalier Universitaire de Nantes
2 U1064 Inserm - CRTI - Centre de Recherche en Transplantation et Immunologie
3 Institut de Transplantation Urologie Néphrologie
4 PAnTher - Physiopathologie Animale et bioThérapie du muscle et du système nerveux
5 Department of Medicine, Transplant Center
6 Department of Obstetrics and Gynecology
7 Immunology Research Center
8 Department of Medicine
9 UE PAO - Unité Expérimentale de Physiologie Animale de l‘Orfrasiére
10 PRC - Physiologie de la reproduction et des comportements [Nouzilly]
11 UMRSV - Unité Mixte de Recherche en Santé Végétale (INRA/ENITA)
12 Laboratorio di Tecnologie della Riproduzione
13 Dipartimento di Scienze Mediche Veterinarie
14 IECM - Immuno-Endocrinologie Cellulaire et Moléculaire

Human corneal allografting is an established procedure to cure corneal blindness. However, a shortage of human donor corneas as well as compounding economic, cultural, and organizational reasons in many countries limit its widespread use. Artificial corneas as well as porcine corneal xenografts have been considered as possible alternatives. To date, all preclinical studies using de-cellularized pig corneas have shown encouraging graft survival results; however, relatively few studies have been conducted in pig to non-human primate (NHP) models, and particularly using genetically engineered donors. In this study, we assessed the potential benefit of using either hCTLA4-Ig transgenic or α1,3-Galactosyl Transferase (GT) Knock-Out (KO) plus transgenic hCD39/hCD55/hCD59/fucosyl-transferase pig lines in an anterior lamellar keratoplasty pig to NHP model. Corneas from transgenic animals expressing hCTLA4-Ig under the transcriptional control of a neuron-specific enolase promoter showed transgene expression in corneal keratocytes of the stroma and expression was maintained after transplantation. Although a first acute rejection episode occurred in all animals during the second week post-keratoplasty, the median final rejection time was 70 days in the hCTLA4-Ig group vs. 21 days in the wild-type (WT) control group. In contrast, no benefit for corneal xenograft survival from the GTKO/transgenic pig line was found. At rejection, cell infiltration in hCTLA4Ig transgenic grafts was mainly composed of macrophages with fewer CD3+ CD4+ and CD79+ cells than in other types of grafts. Anti-donor xenoantibodies increased dramatically between days 9 and 14 post-surgery in all animals. Local expression of the hCTLA4-Ig transgene dampens rejection of xenogeneic corneal grafts in this pig-to-NHP lamellar keratoplasty model. The hCTLA4-Ig transgene seems to target T-cell responses without impacting humoral responses, the control of which would presumably require additional peripheral immunosuppression.

Mots clés: lamellar keratoplasty; pig to non-human primate model; 3-galactosyl transferase knockout; corneal blindness; transgenic pig line; corneal xenograft; alpha1; hctla4-ig

Domaines: Autre [q-bio.OT]

Bertrand Vabres, Stéphanie Le Bas-Bernardet, David Riochet, Yan Cherel, David Minault, et al.. hCTLA4-Ig transgene expression in keratocytes modulates rejection of corneal xenografts in a pig to non-human primate anterior lamellar keratoplasty model. Xenotransplantation, 2014, 21 (5), pp.431-443. ⟨10.1111/xen.12107⟩. ⟨hal-01129941⟩