Endothelial cells are the primary source of G-CSF production during OPC.

(A) CD45⁺ leukocytes, CD45^- EpCAM⁺ CD31^- epithelial cells, and CD45^- EpCAM^- CD31⁺ endothelial cells were isolated from the tongues of naïve and infected WT mice by FACS sorting 24 hours post-infection, and Csf3 mRNA was quantified by qRT-PCR. (B) Tongue cell populations were sorted from the tongues of naïve and infected WT mice as in (A). Cell lysates were generated from the sorted populations and G-CSF protein was quantified in the lysates by ELISA. (C) G-CSF levels were determined in the serum of naïve (n) and infected (inf) WT mice by ELISA. Data are pooled from two (B) or representative of two (A) or five (C) independent experiments. Bar graphs show the group mean + SD. Statistical analysis was performed using Student’s t-test with Welch’s correction.