Gluten T cell epitope targeting by TG3 and TG6; implications for dermatitis herpetiformis and gluten ataxia

Transglutaminase 2 (TG2) is well characterized as the main autoantigen of celiac disease. The ability of TG2 to deamidate and crosslink gluten peptides is essential for the gluten-dependent production of TG2 specific autoantibodies. In patients with primarily extraintestinal manifestation of gluten sensitivity the repertoire of autoantibodies may be different. In dermatitis herpetiformis (DH), TG3 appears to be the target autoantigen whereas in gluten ataxia (GA) autoantibodies reactive with TG6 are present. A functional role for TG3 and TG6 in these diseases has yet to be described. It is also not known whether these enzymes can use gluten peptides implicated in the pathology as substrates. We here report that similar to TG2, TG3 and TG6 can specifically deamidate gluten T cell epitopes. However, the fine specificities of the enzymes were found to differ. TG2 can form covalent complexes with gluten by iso-peptide and thioester bonds. We found that both TG3 and TG6 were able to complex with gluten peptides through thioester linkage although less efficiently than TG2, whereas TG6 but not TG3 was able to form iso-peptide linked complexes. Our findings lend credence to the notion that TG3 and TG6 are involved in the gluten-induced autoimmune responses of DH and GA.     

Isolation of a cultivable spirochete fromIxodes ricinus ticks of Switzerland

We have isolated in BSK medium a spirochete ofIxodes ricinus ticks. The ticks were collected from an area of Switzerland where erythema chronicum migrans, a tick-borne, penicillin-ameliorated inflammatory disorder, is endemic. TheI. ricinus spirochete was very similar in its morphology, polyacrylamide-gel-electrophoresis profile, and antigenic determinants to a spirochete that was previously isolated fromIxodes dammini ticks of the United States.     

Contribution a l'etude de trois especes d'eulophides [Hym. Chalcidoidea] parasites de la tordeuse grise du meleze,Zeiraphera diniana Guenee [Lep. Tortricidae] en haute-engadine

Sans résumé Publication n^o 37 du groupe de travail pour l'étude de la dynamique des populations de la Tordeuse grise du mélèze. Direction: Prof.P. Bovey, Institut d'entomologie de l'école Polytechnique Fédérale, Zurich. étude effectuée avec l'aide d'un subside du Fonds national suisse de la recherche scientifique.     

Simultaneous occurrence of thelytoky and bisexuality in hymenopteran species,and its implications for the biological control of pests

Under this heading, ENTOMOPHAGA publishes short contributions on those aspects of IPM and biological control of pests that are of increasing importance, but have not yet been seriously considered.