Borrelia burgdorferi-pulsed dendritic cells induce a protective immune response against tick-transmitted spirochetes

Borrelia burgdorferi-pulsed dendritic cells and epidermal cells were able to initiate the production of anti-outer surface protein A (OspA) antibody in vitro with normal T and B cells from either BALB/c or C3H/HeJ mice. Inhibition of anti-B. burgdorferi antibody production was observed after 3 days, but not after 2 days, of exposure of the antigen-presenting cells to tumor necrosis factor alpha +/- granulocyte-macrophage colony-stimulating factor. Furthermore, splenic dendritic cells pulsed in vitro with live B. burgdorferi spirochetes and then adoptively transferred into naive syngeneic mice mediated a protective immune response against tick-transmitted spirochetes. This protection appeared not to be due to killing of spirochetes in the feeding ticks, since ticks fed to repletion on B. burgdorferi-pulsed dendritic cell-sensitized mice still harbored live spirochetes. Western blot analysis of the sera collected from dendritic cell-sensitized mice demonstrated that the mice responded to a limited set of B. burgdorferi antigens, including OspA, -B, and -C compared to control groups that either had received unpulsed dendritic cells or were not treated. Finally, mice in the early stage of B. burgdorferi infection were able to develop anti-OspA antibody following injection with B. burgdorferi-pulsed dendritic cells. Our results demonstrate for the first time that adoptive transfer of B. burgdorferi-pulsed dendritic cells induces a protective immune response against tick-transmitted B. burgdorferi and stimulates the production of antibodies specific for a limited set of B. burgdorferi antigens in vivo.