Two dimensional electrophoretic analysis of biosynthetically labelled proteins of Trichostrongylus colubriformis infected larvae.

Summary The proteins and antigens of different life stages of Trichostrongylus colubriformis were compared with those of Ostertagia circumcincta in an attempt to identify the subset of parasite molecules that is genus‐specific and that may therefore be involved in the induction of genus‐specific, host‐protective immunity. Novel short‐term culture techniques were instituted to label biosynthetically the proteins of the infective larval and adult stages of the parasites using 35S‐methionine. High resolution, two‐dimensional electrophoretic profiles of the labelled proteins indicated that the majority of proteins synthesized by adults were also present in the larval stages. Qualitative differences in the levels of these common proteins were observed, indicating differences in protein expression or turnover. There was extensive homology between larvae from the different species, with only eight major differences apparent in their profiles of biosynthetically‐labelled proteins. Western blot analysis using immune sheep sera indicated that extensive homology also existed between the antigens of T. colubriformis and O. circumcincta larvae.