Sarcoptic mange in swine, caused by Sarcotes scabiei var. suis can effect production efficiency in breeding and growing pigs. For routine testing, ELISAs are used, but in single individuals the specificity is not sufficient. This work compared antigen patterns of different protein fractions of S. scabiei and characterised mite-derived antigenic protein bounds by specific serum antibodies from infected pigs.
Sarcoptes mites from foxes, pigs and cattles were collected by using the migration method. Preparations of hydrophilic (phosphate-buffered saline) and hydrophobic (lysis buffer, sodium dodecyl sulphate) fractions were prepared by using Teflon pestle, Ultrasonic homogenizer and centrifugation. SDS-PAGE, preparative isoelectric focussing, western blot and lectin blotting were carried out.
SDS-PAGE revealed multiple bands in the different fractions. Three main bands were located at 40-50 kDa. Hydrophobic S. scabiei antigens were detectable by Western blot in the range of 40-50 kDa, whilst the hydrophilic fraction showed no specific antigenicity. The main bands stained in SDS-PAGE were located at 43,5-45 kDa, in Western blotting at 41-42 kDa. After preparative IEF these three immunoreaktive bands were detected in SDS-PAGE and Western blot in the fractions with pH 5,5-8,5.
In the lectin blots only with SBA and DBA specific bands could be found in the range of 40 and 50 kDa.
In this study it could be demonstrated by using buffers of increasing solubilising power that some PBS-insoluble antigens were recognised by serum antibodies from scabies-infested swine, whilst PBS-soluble antigens showed only weak reactions in Western blotting. It can be assumed that the lack of reactivity of sera in ELISA tests is due to the relatively low antigenicity of the used antigen preparations. Further refinement of antigen and the use of specific hydrophobic proteins could improve ELISA performance and standardisation.
Sarcoptes scabiei / swine / SDS-PAGE / Western blot