A novel adjuvant-free H fusion system for the production of recombinant immunogens in Escherichia coli : Its application to a 12 kDa antigen from Cryptosporidium parvum

Abstract

The production of recombinant antigens in Escherichia coli and specific polyclonal antibodies for diagnosis and therapy is still a challenge for world-wide researchers. Several different strategies have been explored to improve both antigen and antibody production, all of them depending on a successful expression and immunogenicity of the antigen. Gene fusion technology attempted to address these challenges: fusion partners have been applied to optimise recombinant antigen production in E. coli, and to increase protein immunogenicity. Taking a 12-kDa surface adhesion antigen from Cryptosporidium parvum (CP 12) by example, the novel H fusion partner was presented in this work as an attractive option for the development of recombinant immunogens and its adjuvant-free immunisation. The H tag (of only 1 kDa) efficiently triggered a CP 12-specific immune response, and it also improved the immunisation procedure without requiring coadministration of adjuvants. Moreover, polyclonal antibodies raised against the HCP 12 fusion antigen detected native antigen structures displayed on the surface of C. parvum oocysts. The H tag proved to be an advanced strategy and promising technology for the diagnosis and therapy of C. parvum infections in animals and humans, allowing a rapid and simple recombinant production of the CP 12 antigen.