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Ixodes ticks belonging to the Ixodes ricinus complex encode a family of anticomplement proteins
Auteur(s)
Daix, Virginie
Schroeder, Hélène
Praet, N
Georgin, Jean-Pierre
Chiappino, I
Gillet, Laurent
de Fays, Katalin
Decrem, Yves
Leboulle, Gérard
Godfroid, Edmond
Bollen, Alex
Pastoret, Paul-Pierre
Sharp, Paul
Vanderplasschen, Alain
Date de parution
2007
In
Insect Molecular Biology
Vol.
2
No
16
De la page
155
A la page
166
Mots-clés
Résumé
The alternative pathway of complement is an important innate defence against pathogens including ticks. This component of the immune system has selected for pathogens that have evolved countermeasures. Recently, a salivary protein able to inhibit the alternative pathway was cloned from the American tick Ixodes scapularis (Valenzuela et al., 2000; J. Biol. Chem. 275, 18717-18723). Here, we isolated two different sequences, similar to Isac, from the transcriptome of I. ricinus salivary glands. Expression of these sequences revealed that they both encode secreted proteins able to inhibit the complement alternative pathway. These proteins, called I. ricinus anticomplement (IRAC) protein I and II, are coexpressed constitutively in I. ricinus salivary glands and are upregulated during blood feeding. Also, we demonstrated that they are the products of different genes and not of alleles of the same locus. Finally, phylogenetic analyses demonstrate that ticks belonging to the Ixodes ricinus complex encode a family of relatively small anticomplement molecules undergoing diversification by positive Darwinian selection.
Identifiants
Type de publication
journal article
