Chimeric plant virus particles as immunogens for inducing murine and humanimmune responses against human immunodeficiency virus type 1

The high-yield expression of a neutralizing epitope from human immunodefici ency virus type 1 (HIV-1) on the surface of a plant virus and its immunogen icity are presented. The highly conserved ELDKWA epitope from glycoprotein (gp) 41 was expressed as an N-terminal translational fusion with the potato virus X (PVX) coat protein. The resulting chimeric virus particles (CVPs), purified and used to immunize mice intraperitoneally or intranasally, were able to elicit high levels of HIV-1-specific immunoglobulin G (IgG) and Ig A, antibodies. Furthermore, the human immune response to CVPs was studied w ith severe combined immunodeficient mice reconstituted with human periphera l blood lymphocytes (hu-PBL-SCID). hu-PBL-SCID mice immunized with CVP-puls ed autologous dendritic cells were able to mount a specific human primary a ntibody response against the gp41-derived epitope. Notably, sera from both normal and hu-PBL-SCID mice showed an anti-HIV-1-neutralizing activity. Thu s, PVX-based CVPs carrying neutralizing epitopes can offer novel perspectiv es for the development of effective vaccines against HIV and, more generall y, for the design of new vaccination strategies in humans.