Fig. 5

Infection of ST-IOWA cells with cell culture SN of HA-tagged PERV-C(5683). Cells were incubated for 24 h with SN and infection was monitored for 56 days on a weekly basis. Quantification of A envC and B pol vRNA showing increasing copy numbers from the first week on for PERV-C(5683) that was used as positive control as well as for SP-HA and RPep-HA. Non-infected ST-IOWA cells stayed on levels of basal expression. C Quantification of RT activity. RT activity could be detected from day 14 p.i. for all cell lines except for non-infected ST-IOWA cells that served as negative control (ctr−). D Immunohistochemistry of PERV-C-HA infected ST-IOWA cells at day 56 p.i. using PERV-C Env and HA-tag directed antibodies. A1–4 ST-IOWA (ctr−), B1–4 PERV-C(5683) infected ST-IOWA cells (ctr+), C1–4 SP-HA infected ST-IOWA cells, D1–4: RPep-HA infected ST-IOWA cells. In accordance with the transfection studies PERV-C Env-HA was only present in ST-IOWA cells infected with SP-HA or RPep-HA, indicated in green and yellow. Significant means of triplicates of < 0.05 according to Welch’s t-test are indicated by (*)