de novo sequence 

The V and J and C gene segments of antibodies are available in public databases. However, during the maturation of an antibody, the B cell introduces hypermutations into the sequence to optimize the affinity. Our mapping algorithm is error tolerant and can match the “mutated” peptides to the corresponding germline, reliably.

https://www.creative-biolabs.com/next-generation-antibody-sequencing.html