Combinatorial surrobody libraries

Abstract

A unique type of combinatorial protein libraries has been constructed. These libraries are based on the pre-B cell receptor (pre-BCR). The pre-BCR is a protein that is produced during normal development of the antibody repertoire. Unlike that of canonical antibodies, the pre-BCR subunit is a trimer that is composed of an antibody heavy chain paired with two surrogate light chain (SLC) components. Combinatorial libraries based on these pre-BCR proteins in which diverse heavy chains are paired with a fixed SLC were expressed in mammalian, Escherichia coli, and phagemid systems. These libraries contain members that have nanomolar affinity for antigen. We term this type of antigen-binding protein a ''surrobody'' to distinguish it from the canonical antibody molecule.antibody engineering ͉ combinatorial antibody libraries ͉ surrogate light chain

Isolation of a human anti-epidermal growth factor receptor Fab antibody, EG-19-11, with subnanomolar affinity from naïve immunoglobulin repertoires using a hierarchical antibody library system

“…We had previously reported the successful isolation of anti-fluorescein Fab antibodies from a combinatorial Fab diversity of 1.3 × 10 7 heavy chains with only a single light chain constructed in DVS-II [17]. Furthermore, antigen-specific Fab clones have also been successfully isolated from combinatorial libraries in which the antibody repertoire is created by pairing diverse heavy chains with only a single light chain [22,23] or even surrogate light chains [24]. These findings suggest that the number of light chains present in an antibody library may not be a crucial factor for obtaining antibodies with a desired binding specificity.…”

The pre-B cell receptor: turning autoreactivity into self-defense

“…For several reasons it appears unlikely that foreign antigens play a major role in triggering proliferation signals, even though the V H region within the three-dimensional structure of pre-BCRs is capable of binding to foreign antigens [15]. One reason is that the selection criterion for pre-B cells is different from that of mature B cells; whereas B cells are positively selected for the expression of a BCR with appropriate antigen specificity, pre-B cells are positively selected for the expression of a functional mHC, i.e.…”

Mining human antibody repertoires

“…While these partially developed human antibody repertoires are generally not suitable for mining human mAbs, surrobody libraries that pair rearranged heavy chains with surrogate light chains of pre-B cells have been described recently. 13 The ultimate products of B-cell development in the bone marrow are immature B cells that express cell surface IgM. Upon exiting the bone marrow and entering the circulation, immature B cells mature to naïve B cells, the latter of which express cell surface IgD in addition to IgM.…”