![]() ![]() This creates a formidable challenge even for the most advanced screening platforms to mine the entire immune repertoire. The frequency of antigen-specific cells, even after a robust immune reaction, is only between 0.01–0.1% of total B cells 13, 14, 15. However, antibody discovery from immunized animals or convalescent patients, is an intricate process due to the scarcity of antigen-specific cells in a vast diversity of the overall antibody repertoire. The revelation from Dennis Burton’s group that antibodies derived by B-cell cloning had greater therapeutic potency compared to those derived from combinatorial libraries from HIV convalescent patients 3, led to a surge in efforts to discover therapeutic antibodies from immunized animals or convalescent patients 4, 5, 6, 7, 8, 9, 10, 11, 12. As of now there are 129 antibody therapeutics approved or under review in the US and EU 1, 2. Monoclonal antibodies as a promising therapeutic modality are now widely accepted. This antigen-specific B-cell selection technique exemplifies a process improvement with reduced cycle time and cost, by removing undesired clones prior to screening and increasing the chance of capturing desirable and rare functional clones in the repertoire. ![]() We found that cognate chain paired clones and combinatorial clones from AgSC library had higher frequency of functional clones and showed greater diversity in sequence and paratope compared to clones from the TBC library. Furthermore, we compared clones in which cognate chains are preserved with those from display libraries in which chains either from total B cells (TBC) or antigen-specific B cells (AgSC) underwent combinatorial pairing. We also show that this purification is highly efficient with loss of only about 2% antigen specific cells. Using five different antigens, we show hit rates of 51–88%, compared to about 5% with conventional methods. We report on the bulk purification of antigen-specific B-cells and the benefits it offers to various antibody discovery platforms. Current and emerging technologies while effective, are limited in terms of capturing the antigen-specific repertoire. Identifying these cells is akin to finding needle in a haystack. Immunization based antibody discovery is plagued by the paucity of antigen-specific B cells. ![]()
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