Investigation of TLR ligand-generated inflammatory signals for the induction of high magnitude memory CD8+ T lymphocyte responses (42.8)

Abstract

Abstract Most currently used vaccines elicit antibody and CD4+ T lymphocytes, but protection against some pathogens may also require a CD8+ T cell response. We are examining the ability of specific TLR agonists to stimulate a specific third signal, such as IL-12 and type 1 interferons, in bone marrow-derived dendritic cells (BMDC) necessary for appropriate development of antigen-specific memory CD8+ T cells against HSV-2. TLR4 (MPL) and TLR9 (CpG) ligands elicit high IL-12 and low IFN-α/β, while TLR3 (Poly(I:C)) ligands generate the opposite cytokine response. Initial in vitro studies demonstrated that gB peptide-specific CD8+ T cells co-cultured with gB-pulsed, TLR ligand-treated BMDC had a more activated phenotype, but there was little difference in CD8+ T cell proliferation when compared to media-treated BMDC cultures. Upon restimulation, the activated CD8+ T cells produced high quantities of TNF-α, IFN-γ, and granzyme B, but variation between groups was minor. These results suggest the choice of TLR ligand for stimulation had little impact on CD8+ T cells in vitro. Further experiments will focus on examining the lymphoid tissues to which our CD8+ T cells reside, their activation status, cytokine production profiles, and cell surface chemokine receptor expression directed by in vivo delivery of gB-pulsed, TLR ligand-treated BMDC. We believe that different TLR ligands will differentially shape the memory response, in turn, providing greater protection from subsequent infection.