Fig. 2.

The expression of TRIM28 and ACE2 in A549 cells co-cultured with NK-92 cells. (A-C) The NK-92 cells were placed directly on top of A549 cell layer in 12-well culture plates and co-cultured for 12 or 24 h. The mRNA expressions of TRIM28 (A) and ACE2 (B) were analyzed by qPCR method. n = 3. **P < 0.01. (C) Immunoblot analysis was performed to detect expressions of TRIM28 in A549 cells that co-cultured with NK-92 cells for 24 h. Representative blots were shown. The relative expressions of the TRIM28 proteins were quantified by Image J software. n = 3. (D, E) NK cells were cultured in medium in the presence or absence of IL-2 for 24 h, and then placed on top of A549 cell layer for another 24 h. The mRNA expressions of TRIM28 (D) and ACE2 (E) were analyzed by using qPCR method. n = 3. **P < 0.01. (F) NK-92 cell and A549 cells were co-cultured by placing the NK-92 culture inserts on top of the A549 cell layer in transwell culture plates for 24 h. qPCR assay was used to check mRNA expressions of TRIM28 and ACE2 in A549 cells. n = 3. **P < 0.01. (G) The NK-92 cells were placed directly on top of A549 cell layer and co-cultured in medium containing granzyme B inhibitor Z-AAD-CMK (100 μM) for 24 h. TRIM28 and ACE2 expressions were determined by qPCR method. n = 3. **P < 0.01. *P < 0.05.