FIG. 4.

Differential induction of IFN-β mRNA in response to either PR8 or delNS1 virus infection. Confluent 100-mm dishes of HEC-1b cells were infected with either NDV, PR8 virus, or delNS1 virus at an MOI of 1 for 14 h. One dish of mock (PBS)-infected cells was included as a negative control (−). At 14 h postinfection, cells were washed twice with cold PBS, and total RNA was subjected to RT-PCR analysis using specific primers for IFN-β or GAPDH. As a control for genomic DNA contamination, PCR was carried out with GAPDH primers using the mock (−RT) reactions as a template. Following PAGE, products were detected by autoradiography.