| CPC C40B 40/08 (2013.01) | 20 Claims |

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1. A cell-stored barcoded deep mutational scanning library of variants of a viral protein comprising: storage cells, wherein at least 90% of the storage cells comprise a non-self-inactivating viral vector comprising a single homozygous barcoded variant nucleotide sequence encoding a viral protein variant from a set of homozygous barcoded variant nucleotide sequences in the library integrated into the storage cell's genome, wherein the set of homozygous barcoded variant nucleotide sequences collectively encode viral protein variants comprising at least 15 amino acid substitutions at at least 95% of amino acid positions of the viral protein.
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