We silenced CyPA expression in CaLu3 cells before viral infection by transduction with a specific short hairpin RNA (shRNA): CyPA knock down efficiency was 96.0% ± 0.7% of control NT shRNA-transduced cells at the RNA and 95.1% ± 1.0% of control NT shRNA-transduced cells at the protein level. Here, PPIA is linked to viral infectious disease.