Profiling the Response of Rare Cystic Fibrosis Variants to VX-121

Briefly, we first generated a pool of recombinant HEK293T cells in which each individual cell expressed a single CF variant from a uniform genomic locus. We then employed surface immunostaining in conjunction with fluorescent cell sorting in order to separate the pool of cells according to the relative abundance of the CF variants.

We then employed deep sequencing to track the distribution of variants across each cellular isolate, which was then used to comparatively estimate the relative plasma membrane expression of each variant in the presence and absence of VX-121. Similar to our previous observations for VX-661 and VX-445, flow cytometry measurements show that the surface immunostaining of CFTR increases across the recombinant cellular library in the presence of VX-121.