DNA Vaccines Expressing a Fusion Product of Outer Surface Proteins A and C fromBorrelia burgdorferiInduce Protective Antibodies Suitable for Prophylaxis but Not for Resolution of Lyme Disease

Abstract

DNA vaccines encoding the outer surface protein A (OspA) ofBorrelia burgdorferi have been shown to induce protective humoral responses capable of preventing but not curing infection in mice. Subsequent studies showed that an established infection or disease could be resolved by passive transfer of antibodies to OspC. In the present study, DNA vaccines encoding either the OspC antigen alone or fused to OspA and under the transcriptional control of the human elongation factor 1α promoter were evaluated for their protective and/or curative potential. In contrast to ospA-containing plasmids, none of the six constructs with ospC alone were immunogenic in vivo, independent of whether they contained promoter or leader sequences from ospA and/or ospC, or alternatively, the signal sequence of the human tissue plasminogen activator. Solely, a DNA vaccine encoding an OspA-OspC fusion product led to expression of the respective polypeptide chain in transfected cells in vitro and to the induction of OspA- and OspC-specific antibodies in vivo. Immune sera raised against the OspA-OspC fusion product conveyed full protection against subsequent infection, most probably via OspA-specific antibodies, but were unable to resolve infection.

Synthetic bacterial lipopeptide analogs facilitate naive CD4+ T cell differentiation and enhance antigen-specific HLA-II-restricted responses

“…5B). In these settings, the potential of P 3 CSK 4 to restore the antigenicity of MDP-OspA in vitro was even higher than that observed with Lip-OspA, which contains palmitoylated chains covalently linked to its N-terminal cystein [21].…”

“…Previous studies have shown that the immunogenicity of OspA critically depends on its lipidation and that in the absence of adjuvant, only the lipidated derivative, LipOspA, but not the methionine/aspartic acid/proline derivative, MDP-OspA, induces protective antibodies in vivo [20][21][22]. We therefore cultured CFSE-labeled CD4 + T lymphocytes, enriched from PBL of healthy donors, with autologous DC in the presence of MDP-OspA and BLpA and assessed T cell proliferation after 5 days.…”

“…Finally, we investigated the effect of P 3 CSK 4 on CD4 + T cell responses to two HLA-DR-promiscuous, immunodominant epitopes derived from two common human pathogens: TT 947-967 and hepatitis B surface antigen (HBsAg) [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] [23,24]. A higher frequency of peptidespecific T cells in cultures conditioned by P 3 CSK 4 as compared to CSK 4 was demonstrated by LDA analysis (Fig.…”

“…TT, TT 947-967 and HBsAg [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] peptides, and rIL-2 were provided by Dr. A. Wack (Chiron Vaccines, Siena, Italy). GM-CSF was from R&D Systems (Abingdon, UK).…”

“…IL-4-producing cells were a gift from A. Lanzavecchia (IRB, Bellinzona, Switzerland). LipOspA from B. burgdorferi and MDP-OspA have been described [20,21]. All antibodies for FCM were from BD Pharmingen (San Diego, CA); CFSE and 5-(and 6)-(((4-chloromethyl)benzoyl)amino)tetramethylrhodamine (CM-TMR) were from Molecular Probes (Eugene, OR).…”