SH2D3A and infection: Therefore, in all subsequent experiments the number of virions or VLPs used for infection of each cell line was selected according to the individual susceptibilities of the cell lines, e.g. four times more infectious material was used for infection of T-REx-nsP16D cells to achieve the same m.o.i. as for HEK293 T-REx or T-REx-nsP1 cells.