Fig 1.

Susceptibility of the coronavirus TGEV to low‐pH treatment. (A) Treatment at pH 4.0 and 25°C in an IVIG solution. Stability controls (virus spiked into IVIG solution at neutral pH [pH 7.0] and held at process temperature) are shown in light gray. Medium stability controls (virus spiked into titration medium and held at process temperature) are shown in blue. Limits of detection (LOD) are shown for 21‐day test samples (based on cumulated volume of samples with no residual infectivity) and controls only. (B) Treatment at pH 4.0 and 37°C in an IVIG intermediate in presence of PS80. Stability controls (virus spiked into IVIG intermediate at neutral pH [pH 7.0] and held at process temperature) are shown in light gray. LOD is shown for 540‐minute test samples. (A, B) Results of two independent replicates are shown (Run A and Run B). Open symbols indicate when the virus titer has reached the detection limit (no residual infectivity detected). [Color figure can be viewed at wileyonlinelibrary.com]