The invention relates to the molecular characterisation of DNA sequences which encode proteins expressed in the salivary glands of ticks, more particularly the Ixodes ricinus arthropod tick. Genes which are induced in the salivary glands of Ixodes ricinus during the slow-feeding phase of the blood meal were characterized. The cloning of these genes was carried out by setting up a substractive cDNA library by subtracting uninduced cDNAs (synthesised from mRNAs expressed in the salivary glands of unfed ticks) from induced cDNAs (synthesised from mRNAs expressed in the salivary glands at the end of the slow-feeding phase). A full-length cDNA library was set up starting from incomplete sequences deemed of interest and identified in the subtractive cDNA library. Also included in the invention are the various uses of the newly identified polynucleotides and derived polypeptides.