Ex vivo evolution of human antibodies by CRISPR-X: from a naive B cell repertoire to affinity matured antibodies
© The Author(s). 2019
- Published: 18 February 2019
- Human antibodies
Somatic hypermutation promotes affinity maturation of antibodies by targeting the cytidine deaminase AID to antibody genes, followed by antigen-based selection of matured antibodies. Given the importance of antibodies in medicine and research, developing approaches to reproduce this natural phenomenon in cell culture is of some interest.
We use here the CRISPR-Cas 9 based CRISPR-X approach to target AID to antibody genes carried by expression vectors in HEK 293 cells. This directed mutagenesis approach, combined with a highly sensitive antigen-associated magnetic enrichment process, allowed rapid progressive evolution of a human antibody against the Human Leucocyte Antigen A*02:01 allele. Starting from a low affinity monoclonal antibody expressed on Ag-specific naïve blood circulating B cells, we obtained in approximately 6 weeks antibodies with a two log increase in affinity and which retained their specificity.
Our strategy for in vitro affinity maturation of antibodies is applicable to virtually any antigen. It not only allows us to tap into the vast naive B cell repertoire but could also be useful when dealing with antigens that only elicit low affinity antibodies after immunization.