Selection and Characterization of Cell Line–Virus Pairs for Sensitive Viral Detection Assays in Biopharmaceutical Testing

Ensuring viral safety is a critical aspect of biopharmaceutical production, requiring sensitive and reliable methods for detecting adventitious agents. In this study, we systematically evaluated the performance of selected cell line–virus combinations to identify optimal models for in vitro viral detection assays. Three cell lines (Vero, MRC-5 and BHK-21 C-13) and representative model viruses (Reovirus type 3, Adenovirus type 5, Human parainfluenza virus type 3, and Herpes simplex virus) were analyzed in terms of cytopathic effect (CPE) kinetics, morphology, and detection sensitivity. All tested systems demonstrated high analytical sensitivity, with limits of quantification (LOQ) reaching 0.01 TCID50/mL for selected viruses. However, substantial differences were observed in infection dynamics and CPE morphology depending on the cell line–virus combination. BHK-21 C-13 cells exhibited the most rapid and pronounced CPE for Reovirus type 3, enabling early and unambiguous detection. Vero cells provided robust and reproducible detection of Adenovirus type 5, characterized by well-defined cytopathic progression. MRC-5 cells showed controlled and consistent infection kinetics for both Human parainfluenza virus type 3 and Herpes simplex virus, allowing improved temporal resolution and interpretability. These findings demonstrate that assay performance depends not only on sensitivity but also on the kinetics and morphology of infection. Based on combined evaluation criteria, the following optimal cell line–virus pairs were identified: BHK-21 C-13/Reovirus type 3, Vero/Adenovirus type 5, and MRC-5/Human parainfluenza virus type 3 and Herpes simplex virus. The proposed approach supports rational selection of detection models and provides a preliminary descriptive framework for the development of routine visual screening assays in biopharmaceutical quality control.