Cloning and molecular characterization of cDNAs encoding three Ancylostoma ceylanicum secreted proteins.

Ancylostoma ceylanicum belongs to a group of soil-transmitted helminths, which infect almost 576 mln people worldwide and are a major cause of anaemia and malnutrition. Upon contact with a permissive host, third-stage larvae (L3) residing in the environment become activated larvae (ssL3), a process associated with changes in the profile of gene expression. Ancylostoma secreted proteins (ASPs) are the major proteins secreted during larvae activation and play a crucial role in hookworm adaptation to parasitism. Here we report the cloning using RACE-PCR technique of three novel ASPs from the hookworm A. ceylanicum (Ace-asp-3, Ace-asp-4, and Ace-asp-5) and computational analysis of the protein sequences. All three proteins contain SCP (Sperm Coating Protein) domain characteristic for previously described ASP proteins. Real-time PCR analysis shows significant up-regulation of Ace-asp-3 and Ace-asp-5 expression in adult worms and correlated down-regulation in ssL3 larvae. On the other hand, expression of Ace-asp-4 was increased in ssL3 stages and decreased in adult parasites.