Apoptosis is essential for the increased efficacy of alphaviral replicase-based DNA vaccines

• Published in: Vaccine 2004-03, Vol.22 (11), p.1537-1544
• Main Authors: Leitner, Wolfgang W, Hwang, Leroy N, Bergmann-Leitner, Elke S, Finkelstein, Steven E, Frank, Stephan, Restifo, Nicholas P
• Format: Article
• Language: English
• Subjects: Alphavirus; Animals; Antibodies, Viral - analysis; Antibodies, Viral - biosynthesis; Apoptosis; Apoptosis - immunology; Apoptosis - physiology; Applied microbiology; Bcl-X L; bcl-X Protein; Biological and medical sciences; Cancer Vaccines - immunology; Cell Line; Cell Survival - drug effects; Cricetinae; Deoxyribonucleic acid; DNA; DNA - genetics; DNA - immunology; DNA vaccines; Flow Cytometry; Fundamental and applied biological sciences. Psychology; Immune system; Immunogenicity; Kinases; Melanoma; Melanoma - immunology; Mice; Mice, Inbred C57BL; Microbiology; Miscellaneous; Nucleic acids; Plasmids; Plasmids - genetics; Plasmids - immunology; Proto-Oncogene Proteins c-bcl-2 - immunology; Replicon; Sindbis Virus - enzymology; Sindbis Virus - immunology; Transfection; TRP-1 antigen; Vaccines; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, DNA - immunology; Viral Vaccines - immunology; Virology
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2003.10.013

Alphaviral replicons can increase the efficacy and immunogenicity of naked nucleic acid vaccines. To study the impact of apoptosis on this increased effectiveness, we co-delivered an anti-apoptotic gene (Bcl-X L) with the melanocyte/melanoma differentiation antigen TRP-1. Although cells co-transfected with Bcl-X L lived longer, produced more antigen and elicited increased antibody production in vivo, co-delivery of pro-survival Bcl-X L with antigen significantly reduced the ability of the replicase-based vaccine to protect against an aggressive tumor challenge. These data show for the first time that the induction of apoptotic cell death of transfected cells in vivo is required for the increased effectiveness of replicase-based vaccines. Our findings also provide an explanation for the paradoxical observation that replicase-based DNA vaccines are much more immunogenic than conventional constructs despite reduced antigen production.