Antigen-presenting Particle Technology Using Inactivated Surface-engineered Viruses: Induction of Immune Responses Against Infectious Agents

Background: Developments in cell-based and gene-based therapies are emerging as highly promising areas to complement pharmaceuticals, but present day approaches are too cumbersome and thereby limit their clinical usefulness. These shortcomings result in procedures that are too complex and too costly for large-scale applications. To overcome these shortcomings, we described a protein delivery system that incorporates over-expressed proteins into viral particles that are non-infectious and stable at room temperature. The system relies on the biological process of viral egress to incorporate cellular surface proteins while exiting their host cells during lytic and non-lytic infections.

Results: We report here the use of non-infectious surface-engineered virion particles to modulate immunity against three infectious disease agents--human immunodeficiency virus type 1 (HIV-1), herpes simplex virus (HSV), and Influenza. Surface-engineering of particles are accomplished by genetic modification of the host cell surface that produces the egress budding viral particle. Human peripheral blood lymphocytes from healthy donors exposed to CD80/B7.1, CD86/B7.2, and/or antiCD3 single-chain antibody surface-engineered non-infectious HIV-1 and HSV-2 particles stimulate T cell proliferation, whereas particles released from non-modified host cells have no T cell stimulatory activity. In addition to T cell proliferation, HIV-based particles specifically suppress HIV-1 replication (both monocytotropic and lymphocytotropic strains) 55 to 96% and HSV-based particles specifically induce cross-reactive HSV-1/HSV-2 anti-herpes virus antibody production. Similar surface engineering of influenza-based particles did not modify the intrinsic ability of influenza particles to stimulate T cell proliferation, but did bestow on the engineered particles the ability to induce cross-strain anti-influenza antibody production.

Conclusion: We propose that non-infectious viral particles can be surface-engineered to produce antigen-presenting particles that mimic antigen-presenting cells to induce immune responses in human peripheral blood lymphocytes. The viral particles behave as "biological carriers" for recombinant proteins, thereby establishing a new therapeutic paradigm for molecular medicine.