Cutting edge: Protective effect of CX3CR1+ dendritic cells in a vaccinia virus pulmonary infection model.

The protective host immune response to viral infections requires both effective innate and adaptive immune responses. Cross-talk between the two responses is coordinated by the chemokine network and professional APCs such as dendritic cells (DCs). In mice, subpopulations of myeloid DCs in peripheral tissues such as lungs and in blood express CX3CR1 depending on the inflammation state. We thus examined the host response of mice deficient in the chemokine receptor CX3CR1 to an intranasal vaccinia virus infection. CX3CR1-deficient mice displayed significantly more severe morbidity and mortality compared with control wild-type mice within 10 d following vaccinia virus infection. CX3CR1(-/-) mice had increased viral loads and a reduced T cell response compared with wild-type mice. Finally, an adoptive transfer of CX3CR1(+/+) DCs completely protected CX3CR1(-/-) mice to a previously lethal infection. This study therefore opens up the possibility of novel antiviral therapeutics targeting lung DC recruitment.