Quantification of TAM receptor/ligand and cytokine mRNA expression.

Cells were lysed in TRIzol reagent (Invitrogen) and stored at −80°C. Total RNA extraction and reverse transcription were performed according to manufacturer's instructions (Qiagen, Hilden, Germany). Individual gene expression was analyzed by PCR using specific TaqMan probes to assess expression relative to Gapdh (housekeeping gene). Fold change calculations were done using the −ΔΔ threshold cycle method.