Innate immune system has evolved to protect the host from invading pathogens, which relies on strictly conserved pattern recognition receptors (PRRs) that recognize conserved pathogen-associated molecular patterns (PAMPs) synthesized by bacteria or virus. The best characterized receptors that recognize PAMPs are TLRs that are expressed on a wide variety of cells including epithelial cells, macrophages, DCs, NK cells, B, and T cells in the FGT (reviewed in ref. 20). All major TLRs (1–10) are expressed by the human genital tract cells.21,30–34 Of the ten TLRs, TLR3, TLR4, TLR7, TLR8, and TLR9 have been known as antiviral TLRs because they preferentially induce the production of antiviral interferons, IFN-α/β, and IFN-λ. Four of these TLRs including TLRs 3, 7, 8, and 9 reside in the endosome in most cell types and can be stimulated by viral nucleic acid agonists, double-stranded RNA, imidazoquinoline/loxoribine, single-stranded RNAs, and non-methylated CpG ODN, respectively. Exploiting TLR signaling, as well as searching for new PAMPs/ligands possessing potent innate immune capability but lesser side effects is the main focus of today’s sexually transmitted virus research to generate a more comprehensive vaccine or therapeutic interventions. TLR ligand stimulation triggers local inflammation, recruitment of effector cells, and secretion of cytokines/chemokines that modulate both innate and adaptive immune responses.35–37 A few recent important studies utilizing TLR ligands have been successful to provide protection against the devastating STI, HSV-2 in murine model. In this regard, we and others have demonstrated that local delivery of CpG ODN, a TLR9 agonist, through the genital tract provide complete protection of mice from subsequent lethal challenge by vaginal HSV-2.38–41 Mechanistically, local delivery of CpG ODN induces proliferation and thickening of the genital epithelial cells, huge influx of inflammatory cells into the submucosa, and arrests HSV-2 replication but not entry into the genital tract.38,40,42 We further showed that local delivery of TLR3 ligand poly I:C robustly protects mice from intravaginal HSV-2 challenge, which is independent of any local inflammatory reactions43 that is observed with CpG treatment. These two studies indicate distinct mode of responses; while TLR9 ligand inhibits HSV-2 infection through Th1 (pro-inflammatory) inflammation, TLR3 stimulation, in contrast, acts independent of inflammation. Moreover, TLR9 stimulation by CpG results in the expansion of CD8+ T cells and destruction of lymphoid tissues with consequent development of immunosuppression and B cell-related autoimmunity; in contrast, dsRNA-mediated responses are much solid and safer without causing any adverse immunopathological effects. Intravaginal inoculation of poly I:C also found to induce array of innate cytokines/chemokines such as IFN-α, IL-1α, IL-1β, IL-6, IFN-γ/MIP-1α, and RANTES production in the genital tract39,44 and IFN-β release by epithelial cells.45 Therefore, CpG and poly I:C could be potential candidate microbicide for local protection against genital HSV-2 or HIV-1 infections that deserve further studies. As in the case of HIV-1, TLR-3 ligand poly I:C stimulation of genital tract displayed conflicting results; while one study shows poly I:C prevents HIV-1 transmission,46 conversely, the other study found poly I:C as a potent inducer of Langerhans’ cell maturation and HIV-1 transmission.11 More recently, treatments of human primary uterine cell culture ex vivo with TLR-3, 9, and 5 ligands poly I:C, CpG ODN and flagellin, respectively, resulted in 80% inhibition of HSV-2 replication, but only TLR3 stimulation produced significant amounts IFN-β, IL-1β, IL-6, and TNF-α through IRF-3 and NF-kB activation.31 Further evidence that the TLR3 ligand poly I:C induces TH1 response in an HIV-gag protein vaccine depends on MDA-5-mediated recognition in both hematopoietic and stromal cell compartments.47 A more recent study, however, described contrasting roles of TLR5 and TLR9 ligands, flagellin, and CpG ODN, respectively; while flagellin enhances the CCR5- and CCR4-tropic HIV-1 replication, treatment with CpG ODN suppressed both viral variants in lymphoid tissue ex vivo that correlated with CCL3, CCL4 and CCL 5 and CXCL10 and CXCL12 and T-cell activation leading to HIV-1 pathology.48 Similarly, Funderburg et al49 showed differential activation of CD8+ T-cell and CD4+ T-cell responses with HIV-1 infection upon TLR ligands’ (TLR2-9) treatments of human PBMCs ex vivo.