[1] Inst Pasteur, Unite Pathogenie Microbienne Mol, F-75724 Paris 15, France
[2] Inst Pasteur, INSERM, U389, F-75724 Paris 15, France
[3] Inst Pasteur, Unite Rech & Expertise Histotechnol & Pathol, F-75724 Paris 15, France
[4] Univ Cambridge, Dept Clin Vet Med, Ctr Vet Sci, Cambridge CB3 0ES, England
[5] Huddinge Univ Hosp, Karolinska Inst, Clin Res Ctr, Stockholm, Sweden
[6] Scripps Res Inst, Dept Immunol, La Jolla, CA 92037 USA