Structural studies aimed at improving the antigenicity of congopain.

摘要: African animal trypanosomosis or nagana is a tsetse fly-transmitted disease, caused by Trypanosoma congolense, T. vivax and to lesser extent brucei brucei. The disease causes major losses in revenue many livestock-producing countries. available control methods, including chemotherapeutic drugs insecticidal spraying, have become environmentally unacceptable. Antigenic variation displayed the parasites has hindered vaccine development efforts. In this context, rather than focusing solely on parasite itself, efforts shifted towards targeting pathogenic factors released the parasites during infection. Congopain, cysteine protease of been shown act as factor process. Analysis immune response trypano-tolerant cattle revealed that these animals ability congopain activity vivo. Therefore, an attractive candidate. To test protective potential congopain, immunisation studies had conducted using baculovirus-expressed catalytic domain (C2) RWL, saponin-based proprietary adjuvant from SmithKline-Beecham. Immunised were partially protected against infection with T.congolense. Unfortunately, subsequent attempts reproduce results disappointing. It was hypothesised failure could be due different expression system (P. pastoris) used produce antigen (C2), adjuvant, ISA206 (Seppic), used, thus hinting epitope presentation problem. Congopain dimerise at physiological pH vitro. Sera preferentially recognised dimer conformation, advocating for epitopes associated. For reason, present study aimed at improving antigenicity through firstly, elucidation of the associated dimer, secondly, determination 3-D structure order map later design mimotopes, thirdly improve delivery cells while maintaining the conformation molecular BiP. A dimerisation model was proposed, identifying amino acid residues forming motif congopain. study, particular located mutated PCR-based site-directed mutagenesis generate mutants capabilities. expressed yeast their capability assessed PhastGel® SDS-PAGE. mutations altered both electrophoretic mobility enzymatic characteristics compared wild-type This advocated involvement process, although they seem not only partakers. Wild-type C2 mutant forms were…