Isolation of the antimicrobial peptide gene (defensin) from the hard tick \kur{Ixodes ricinus}, challenged by the pathogen infection

Antimicrobial peptides are major components of the innate immune response of epithelial cells. In hematophagous organisms, which acts as vectors of parasitic diseases, in particular Lyme borreliosis, the gut pathogen induce the expression of defensin, that provide the first barier of host defence. This raises the posibility that defensin may play a key role in the development of parasitic infection. The gene expressed in midgut was isolated from cDNA of the hard tick, Ixodes ricinus. The gene is coding the protein, that is produced and secreted during tick infection, and is known as defensin. Expression of the gene for defensin (224 bp) was induced by the pathogen. The gene was cloned into bacterial expression system