CD69 is expressed on pDCs and is further increased upon influenza infection. (A) C57Bl/6 mice were infected with influenza virus or PBS intraperitoneally. After 18 hours, CD69 expression on the surface of lymphocytes and pDCs was determined by flow cytometry. The value of CD69 was expressed as the average mean fluorescence intensity on cells from 5 mice (i) or as the fold-induction of CD69 on different cell types induced by influenza infection (ii). A representative histogram of CD69 expression on pDC is shown (iii). The experiment is a representative example of at least 5 independent experiments. (B) C57Bl/6 mice were injected with 105 U IFN-α, IFN-β, or a combination of 105 U of each IFN. After 18 hours, CD69 expression on the surface of lymphocytes and pDCs were determined by flow cytometry. The value of CD69 was expressed as the average mean fluorescence intensity on cells from 5 mice. *P < .05.
