Creating a nativeness score for humans and VHHs using a variant of variational auto-encoder (VAE).
They used approximately 2m sequences for heavy, kappa, lambda and nanobody each.
Model is VQ-VAE trained on masked language modeling objective with VAE-specific terms incorporated in the loss function.
The nativeness definition is a transformation of the |x_r - x_n|, that is the MSE of the original and reconstructed sequence.
They used the data from the ‘universal Nb framework’ paper to perform VHH grafting experiments.
They tested against other methods whether they could predict human vs non-human sequence (humanized, chimeric, mouse), they are the best with pr AUC of 975. Closest was Oasis and Germline content with pr AUC of .963
ADA on 126 therapeutics shows r2 of .25.
As a nanobody humanization case-study they employed antibodies from another paper that offer WT and humanized variants. They show that their score moves the humanized variants closer to the human distribution - but human and VHH humannesses are still far separated.
When they have species-matched predictions, they call it nativeness. If they score VHH on human models, they call it humanness.