The interplay of macrophages and dendritic cells with WNV-specific T cells during single-cycle flavivirus immunization. (P6332)

Abstract

Innate immunity is important to control the early phase of infection. Macrophages and dendritic cells (DCs) play a critical role in the initial stages of immune responses to several viruses, serving as antigen-presenting cells (APCs), especially DCs, which are potent APCs and play an essential role in the induction and control of the cell-mediated immune response. Here we investigated the role of macrophages in dissemination of single-cycle flavivirus (SCFV) particles to draining lymph nodes (LN) following footpad (FP) inoculation and evaluated the APC function in the absence of macrophages. Our results demonstrated higher virus replication in the absence of macrophages and a wider spread of the particles from the initial site of infection, demonstrating that macrophages were important in the early control of the virus. On the other hand, we demonstrated that macrophages were not critical for the induction of WNV-specific CD8+ T cell response, since similar responses were observed in the presence or absence of macrophages. Further, we began to investigate the function of the TLR3, IRF3 and IFNαβR signaling pathways in the migration and activation of specific DC populations into the regional LN of mice inoculated with SCFV via FP injection. Although we found differences in the number of DCs recruited to the site of infection, our preliminary results suggest similar activation and APC function of DC from mice lacking these innate pathways.