Vet. Res. 34 (2003) 791-801
DOI: 10.1051/vetres:2003033

Cross-species reactivity of seven monoclonal antibodies with equine lymphocytes by flow cytometry

Catherine Mérant^{a, b}, Catherine Bonnefont^{a, b}, Agnès Desbos^c, Timothy Greenland^d, Jean-Luc Cadoré^d and Jean-Claude Monier<sup>a

a</sup>  Laboratoire d'Immunopathologie, Service de Médecine, Département des Animaux de Compagnie, École Vétérinaire de Lyon, BP 83, 1 avenue Bourgelat, 69280 Marcy-l'Étoile, France
^b  Present address: AFSSA Ploufragan, Unité de Virologie et Immunologie Porcines, Zoopôle des Côtes d'Armor, Les Croix, BP 53, 22440 Ploufragan, France
^c  UF d'Auto-Immunité, Centre Hospitalier Lyon Sud, Pierre-Bénite, France
^d  UMR 754, INRA-ENVL-UCBL, Lyon, France

(Received 9 July 2002; accepted 12 June 2003)

Abstract
The recognition of equine lymphocyte antigens by monoclonal antibodies (mAbs) directed against human CD11a, CD18, CD21, CD23, CD29 and DR, as well as mouse CD23 was studied by flow cytometry. Unlike anti-CD11a, -CD21, -CD23 and DR mAbs, anti-CD18 and CD29 mAbs labelled the same percentage of horse peripheral blood lymphocytes (PBL) as human PBL. Double-staining with anti-horse immunoglobulin antibodies showed that anti-CD21 and -CD23 mAbs are mainly bound to peripheral blood B lymphocytes. The seven mAbs were also tested on the lymph node and thymus cells. The molecular targets of anti-CD11a, CD18 and CD29 mAbs were confirmed by immunoprecipitation of the membrane proteins. Our results suggest that anti-CD18, -CD29 and -DR mAbs recognise similarly expressed molecular homologues on equine cells, but that anti-CD11a, -CD21 and -CD23 mAbs recognise either different molecules or homologues that are expressed at different levels on horse cells.

Key words: horse / lymphocyte / leukocyte antigen / monoclonal antibody / cross-reaction

Correspondence and reprints: Catherine Mérant c.merant@ploufragan.afssa.fr

© INRA, EDP Sciences 2003