PMID: 15886091 TLR signaling induces a significant change in the phenotype of DCs, referred to as DC maturation. PMID: 15886091 This process is characterized by enhanced expression of co-stimulatory molecules and major histocompatibility complex (MHC)?peptide complexes, and increased secretion of cytokines necessary for activation and polarization of naive T cells (i.e. T cells that have never responded to antigen).

PMID: 15886091 In the case of viruses capable of infecting DCs, a TLR-independent recognition of dsRNA occurs. It has been shown that PKR and RNAseL are involved in this alternative pathway, which may synergize with TLR3 signaling.

PMID: 15886091, 15711573 As TLR3 is predominantly expressed in CD8¦Á+ DCs in mice, Reis e Sousa and colleagues [10] set out to investigate whether recognition of dsRNA in apoptotic bodies from virus-infected cells allows CD8¦Á+ DCs to prime an immune response to viruses that are unable to infect DCs directly. CD8alpha+ DCs underwent phenotypic maturation and secreted inflammatory cytokines when exposed to apoptotic cells loaded with dsRNA but not to unloaded controls.

PMID: 15886091, 11607032 TLR3 is an endosomal Toll-like receptor that recognizes double-stranded (ds) RNA [11], a by-product of most viral infections.

PMID: 15886091 This process is characterized by enhanced expression of co-stimulatory molecules and major histocompatibility complex (MHC)?peptide complexes, and increased secretion of cytokines necessary for activation and polarization of naive T cells (i.e. T cells that have never responded to antigen).

PMID: 15886091 This process is characterized by enhanced expression of co-stimulatory molecules and major histocompatibility complex (MHC)?peptide complexes, and increased secretion of cytokines necessary for activation and polarization of naive T cells (i.e. T cells that have never responded to antigen).

PMID: 15886091 This process is characterized by enhanced expression of co-stimulatory molecules and major histocompatibility complex (MHC)?peptide complexes, and increased secretion of cytokines necessary for activation and polarization of naive T cells (i.e. T cells that have never responded to antigen).

PMID: 15886091 The viral dsRNA contained within the apoptotic bodies is recognized by endosomal TLR3, inducing NFkappaB activation and DC maturation.

PMID: 15886091 The viral dsRNA contained within the apoptotic bodies is recognized by endosomal TLR3, inducing NFkappaB activation and DC maturation PMID: 15886091 DC maturation and cross-priming can be enhanced by type I IFN released by infected cells. PMID: 15886091, 15711573 In a recent paper published in Nature [10], the group of Reis e Sousa has shed some light on this issue and elegantly demonstrated that signaling via TLR3 promotes cross-priming of virus-specific T-cell responses by ensuring the maturation of immature CD8alpha+ DCs that have taken up apoptotic bodies from virus-infected cells.

PMID: 15886091 DC maturation and cross-priming can be enhanced by type I IFN released by infected cells.

PMID: 15886091 In the case of viruses capable of infecting DCs, a TLR-independent recognition of dsRNA occurs. It has been shown that PKR and RNAseL are involved in this alternative pathway, which may synergize with TLR3 signaling.