<;P>;PROBLEM TO BE SOLVED: To provide a new polypeptide and a new polynucleotide useful for exterminating ixodids or therapy or prophylaxis of ixodid-mediated infectious diseases. <;P>;SOLUTION: The polypeptide is new LKR and SDH. The polypeptide, the polynucleotide encoding the polypeptide, or a vector comprising the polynucleotide is useful for exterminating the ixodids or the therapy or the prophylaxis of the ixodid-mediated infectious diseases. An inhibitor of the polypeptide or an antibody against the polypeptide is also useful for exterminating the ixodids or the therapy or the prophylaxis of the ixodid-mediated infectious diseases. <;P>;COPYRIGHT: (C)2010,JPO&INPIT