| abstract |
Disclosed herein are isolated immunogens including variant hepatitis B surface antigens (HBsAgs). In an example, a variant HBsAg includes a HBsAg with one or more transmembrane domains of the HBsAg replaced with a gp41 antigenic insert. The antigenic insert can include an antigenic polypeptide fragment of gp41 including the membrane proximal region of gp41 and a transmembrane membrane region of gp41. The replacement of a membrane spanning domain of HBsAg with a membrane spanning domain of gp41 anchors gp41 into HBsAg in virtually the identical orientation as on HIV virions and correctly orients the nearby MPR on the lipid layer. Thus, the disclosed variant HBsAgs display the neutralization-sensitive MPR in association with a lipid layer, while presenting it at the most immunogenic site on HBsAg. Also disclosed are uses of these variant HBsAgs, and nucleic acids encoding variant HBsAgs, such as to induce an immune response to HIV-1. |