ICAM1 and infection: These results demonstrated that both THP-1 and Kasumi-1 cells remained resistant to CVA21-direct oncolysis despite a greater than 10-fold increase in ICAM-1 expression (Additional file 4: Figure S3B and C); moreover, plaque assays confirmed that there was no increase in CVA21 titre, compared to input virus, 72 h post-infection (data not shown).