Identification of Somatic Proteins in Haemonchus Contortus Infective Larvae (L₃) and Adults

Haemonchus contortus is considered the most pathogenic nematode in sheep production systems based on grazing. Comparing infective larvae (L₃) with adult parasites can lead to the identification of proteins that play an important role in parasite-host interactions. In this study, we report a list of H. contortus somatic proteins and made a comparative analysis of somatic proteins of L₃ and adult worms. L₃ and adult parasites were subjected to protein extraction and subsequently to peptide fractionation. Peptides were analysed by mass spectrometry and LC-MS/MS data analysis. Data analysis and search on SEQUEST and MASCOT against H. contortus from the WormBase ParaSite database resulted in the identification of 775 unique peptide sequences corresponding to 227 proteins at 1 % FDR. From these, 18 proteins were specific to L₃ and 63 to adult parasites. The gene ontology (GO) enrichment analysis of the proteins specific to L₃ and adult worms to gain insight into cellular components, molecular functions and biological processes that affect the parasite-host interaction showed some differences between the two parasite stages. The list of proteins found provides a database to identify target proteins that could be useful as biomarkers of the infection or in the generation of anthelmintic drugs that inhibit proteins essential for the establishment of the infection and the survival of adult parasites. They can also serve as new candidates for vaccine research.