Improvement of the immune response against plasmid DNA encoding OspC of Borrelia by an ER-targeting leader sequence

The present study outlines the characterization of a DNA-based immune respo nse against the OspC antigen, one of the most promising candidates for a Bo rrelia vaccine. Balb/c mice were injected intradermally with plasmid DNA en coding the OspC gene (lacking the natural leader sequence) under transcript ional control of the cytomegalovirus (CMV) promotor. Immunization with this construct elicited only a marginal response, which was drastically improve d by a fusion construct containing the human tissue plasminogen activator ( hTPA) signal sequence. The results indicate that for DNA-based immunization against OspC an ER-targeting signal may be necessary for both antibody pro duction as well as cellular immune responses. (C) 1999 Elsevier Science Ltd . All rights reserved.