1. ¹University Clinic of Tübingen, Department of Internal Medicine II, Division of Hematology and Immunology, Tübingen, Germany
2. ²Medical University Clinic of Vienna, Department of Internal Medicine I, Division of Hematology and Hemostaseology, Vienna, Austria
3. ³University of Tübingen, Proteome Center, Tübingen, Germany
4. ⁴University Clinic of Tübingen, Department of Dermatology, Tübingen, Germany

Correspondence: BÜHRING Hans-Jörg, Medizinische Klinik II, Otfried-Müller-Str.10, 72076 Tübingen, Germany Tel: +49-7071-2982730; Fax: +49-7071-292730; E-mail: hans-joerg.buehring@uni-tuebingen.de

Received 11 November 2004; Revised 9 March 2005; Accepted 16 March 2005.

Abstract

Using two-colour flow cytometry >200 antibodies submitted to the 8^th International Workshop of Human Leukocyte Differentiation Antigens (HLDA8) have been analyzed for their reactivity with resting and activated CD203c⁺ basophils. Four antibodies either non-reactive or weakly reactive with resting basophils exhibited an increased reactivity with basophils activated by anti-IgE-mediated cross-linking of the high affinity IgE receptor (FcRI). These include antibodies against CD164 (WS-80160, clone N6B6 and WS-80162, clone 67D2), as well as two reagents with previously unknown specificities that were identified as CD13 (WS-80274, clone A8) and CD107a (WS-80280, clone E63-880). The activation patterns followed either the "CD203c-like" or "CD63-like" activation profile. The CD203c profile is characterized by a rapid and significant upregulation (of CD13, CD164, and CD203c), reaching maximum levels after 5-15 min of stimulation. The phosphoinositide-3-kinase (PI3K)-specific inhibitor wortmannin inhibited the upregulation of these markers whereas 12-O-tetradecanoyl-phorbol-13-acetate (TPA) induced a rapid and FcRI-independent upregulation within 1-2 min. In the CD63 profile, maximum upregulation (of CD63 and CD107a) was detected only after 20-40 min, and upregulation by TPA reached maximum levels after 60 min. In summary, our data identify CD13, CD107a, and CD164 as novel basophil-activation antigens. Based on time kinetics of upregulation, we hypothesize that molecules of the "CD203c group" and the "CD63 group" are linked to two different mechanisms of basophil activation.