Search

Competing Interests: Competing interests L.S., F.F., R.D., T.J.P., K.P.-S., S.D., M.F.E. and A.R.M.B. are employees of Specifica, an IQVIA business. O.H., C.L.-L. and Y.Q. are employees of Sanofi. H.G.N. and K.R. are employees of Incyte and stockholders. M. Shahsavarian is an employee of Eli Lilly. D.B. is an employee of Carterra. R.W. is an employee of Bonito Biosciences. C.M.D. discloses membership of the Scientific Advisory Board of Fusion Antibodies and AI proteins. P.M.T. is a member of the scientific advisory board for Nabla Bio, Aureka Biotechnologies, and Dualitas Therapeutics. P.M., E.V. and R.A. are employees of Novo Nordisk A/S. J.S. is an employee of OpenEye, Cadence Molecular Sciences. R.C.W. is an employee of AstraZeneca. A.E. and C.S. are employees of Merck Healthcare KGaA. S.B. is an employee of Evolutionary Scale. J.R. is an employee of Profluent Bio. S.F. is an employee of Alloy Therapeutics. V.B.K., S.M. and S.K. are employees of Takeda. P.K. is an employee of Cradle Bio. J.C.A. is an employee of GlobalBio. E.F., M. Stanton and C.P.G. are employees of Mosaic Biosciences. S.D.V. and F.T. are employees of Bayer A.G. All other authors declare no competing interests.

Combinatorial libraries of rearranged hypervariable V(H) and V(L) sequences from nonimmunized human donors contain antigen specificities, including anti-self reactivities, created by random pairing of V(H)s and V(L)s. Somatic hypermutation of immunoglobulin genes, however, is critical in the generation of high-affinity antibodies in vivo and occurs only after immunization. Thus, in combinatorial phage display libraries from nonimmunized donors, high-affinity antibodies are rarely found. Lengthy in vitro affinity maturation is often needed to improve antibodies from such libraries. We report the construction of human Fab libraries having a unique combination of immunoglobulin sequences captured from human donors and synthetic diversity in key antigen contact sites in heavy-chain complementarity-determining regions 1 and 2. The success of this strategy is demonstrated by identifying many monovalent Fabs against multiple therapeutic targets that show higher affinities than approved therapeutic antibodies. This very often circumvents the need for affinity maturation, accelerating discovery of antibody drug candidates.