Abstract
Introduction. Induced pluripotent stem cells (iPSCs) hold promises for disease modelling and regenerative medicine, but reprogramming efficiency and safety depend on the method used to deliver Yamanaka factors (OCT4, SOX2, KLF4, c-MYC). Lentiviral vectors offer high efficiency yet risk insertional mutagenesis, while non-integrating Sendai virus systems provide transient transgene expression. Aim.This study aimed to compare these two commonly used delivery strategies by reprogramming primary human lung fibroblasts using both doxycycline-inducible lentiviral vectors and a non-integrating Sendai virus system. Materials and Methods.Primary human fetal lung fibroblasts (20–21 weeks of gestation) were isolated via explant culture and reprogrammed using either doxycycline-inducible lentiviral vectors encoding OKSM factors or a Sendai virus-based kit (CytoTune 2.0). Emerging iPSC colonies were expanded and characterized by immunofluorescence for pluripotency markers (SSEA4, OCT4, TRA-1-60) and alkaline phosphatase (ALP) activity. Results. Both methods generated iPSC colonies with typical morphology (compact structure, high nucleus-to-cytoplasm ratio). Colony emergence occurred on days 15-20 in both lentiviral and Sendai virus reprogramming systems. Immunofluorescence confirmed expression of SSEA4, OCT4, and TRA-1-60 in colonies from both approaches, and ALP staining was positive. Conclusion. Primary human fetal lung fibroblasts can be reprogrammed into iPSCs using both integrating lentiviral and non-integrating Sendai virus systems. Both methods yield stable iPSC lines with proper characteristics. The choice of method depends on the required balance between efficiency and genomic safety. Key words: lung fibroblasts, induced pluripotent stem cells, lentivirus, Sendai virus, reprogramming.