Comparison of mutations in human parainfluenza viruses during passage in primary human bronchial/tracheal epithelial air-liquid interface cultures and cell lines

Laboratory cell lines are essential for viral studies, providing also a cost effective alternative to animal models for propagating and characterizing viruses. Human parainfluenza viruses (HPIVs) are major causes of respiratory illnesses in pediatrics and geriatrics, making use of cells lines in vaccine development vital. However serial passage in standard cell lines often forces viruses to adapt to artificial environments. This selective pressure induces mutations that alter biological processes, yielding findings that do not accurately represent clinical behavior. While this phenomenon is well-documented in HPIV3, data for other HPIV types remain scarce. This study passaged HPIV1–4 five times in 3 cell lines; primary human bronchial/tracheal epithelial cells grown in an air-liquid interface (HBTEC-ALI), Vero cells and Vero cells expressing TMPRSS2. Findings revealed that the HBTEC-ALI, which mimic the human airway, maintained better genomic integrity with minimal mutations. In contrast, rapid and significant mutations, especially within the Hemagglutinin-neuraminidase (HN) and Large (L) protein genes were induced in Vero-based lines. Although HBTEC-ALI is the superior model, further validation requires more passages, comparison with other human respiratory cell lines and functional assays to determine how these mutations affect viral properties such as replication and drug resistance.
(SWM)