A Preliminary Study on the Antigenic Proteins of Linguatula serrata Nymphal Stage in Sheep with Visceral Linguatulosis.

Scant information is available on the immunological aspect of Linguatula serrata causing linguatulosis in humans and animals. The present study aimed to analyze the content of crude somatic extracts and excretory-secretory products of L. serrata nymphs to detect the immune response of sheep and immunogenic proteins of the parasite. After collecting the nymphs, somatic extracts were prepared by sonication. Excretory secretory products were prepared by the incubation of nymphs in RPMI medium at 37°C with 5% CO2. Somatic and excretory-secretory proteins were isolated using SDS-PAGE. The immunogenic properties of the resulting proteins were determined using immunoblotting and positive sera from sheep infected with visceral linguatulosis. The total content of somatic extracts and excretory-secretory products of L. serrata nymphs analyzed by SDS-PAGE (12% gel) revealed two protein patterns with more than 18 and 9 strong bands, respectively. Immunoblots using sera samples of sheep infected with the parasite, somatic extracts and excretory-secretory products demonstrated 12 and 3 antigenic proteins with molecular weights mostly in the range of 24-100 kDa and an antigen more than 180 kDa. Three common immunodominant antigenic proteins with molecular weights of 38 and 57, as well as an antigen of more than 180 kDa, were detected in the somatic extracts and excretory-secretory products of L. serrata nymphs in sheep with visceral linguatulosis. These antigens can be considetered prime candidates for future serodiagnosis and immunoprotective studies of the parasite.