"Together, we propose that the stability of the spike in the extracellular milieu can be different for SARS-CoV-2 variants, which mainly affects the efficiency of infection of cells with low ACE2 levels. In this context, we identified a human bronchial cell line, NCI-H1299 cells, with undetectable ACE2 protein expression levels to be used as a model cell line for extended SARS-CoV-2 infection stability studies in the future."

https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001871#sec010