Identification of a polyI:C-inducible membrane protein that participates in dendritic cell–mediated natural killer cell activation

INAM-mediated induction of TRAIL and granzyme B in NK cells. (A) In vitro induction of TRAIL (Tnfsf10) and granzyme B (Gzmb) mRNA in NK cells by INAM-expressing BMDC. BMDCs (IRF-3^−/−) were infected with INAM-expressing virus or CV as in Fig. S4. After 24 h, the BMDCs (IRF-3^−/−) were incubated with WT NK cells at DC/NK = 1:2. 8 h later, DX5⁺ cells were collected by FACS sorting and their RNA was extracted to determine the mRNA levels of the indicated genes. A representative result of three similar experiments are shown. (B) In vivo induction of TRAIL and granzyme B mRNA in NK cells by INAM-expressing BMDC. WT BMDCs were stimulated with 10 μg/ml polyI:C or medium only. IRF-3^−/− BMDCs were infected with CV or INAM-expressing vector. These BMDCs were allowed to stand for 24 h and then 5 × 10⁵ cells were injected into footpads of WT mice. After 48 h, DX5⁺ cells were collected from the inguinal LN by FACS sorting. RNA of the cells was extracted and the levels of the indicated mRNA were determined by real time PCR. Data show one of two experiments with similar results. Data in A and B represent mean ± SD.