Recombinant subunits as tools for the structural and functional characterization of Echinococcus granulosus antigen B.

Antigen B (AgB) is a major protein component of the Echinococcus granulosus metacestode. It is oligomeric and this raises several questions regarding the subunit structure and composition of AgB. Several genes that encode different AgB subunits have been identified, and some of these have been cloned and expressed to produce recombinant subunits. The study of these recombinant subunits may provide new insights into the structure, physical-chemical properties, and functional aspects of AgB. Like native AgB, the AgB8/1, AgB8/2, and AgB8/3 recombinant subunits produced in our laboratory form 120-160 kDa oligomers that have stable secondary structures, are strongly antigenic and immunogenic, and selectively bind hydrophobic compounds. Here, we review these results and discuss their implications for the elucidation of the structure and function of AgB. This includes a possible role for AgB in host-parasite interactions.