Genetic manipulation of B cells for the isolation of rare therapeutic antibodies from the human repertoire

Antibody based therapies are increasingly applied to prevent and treat human disease. While the majority of antibodies currently on the market are chimeric or humanized antibodies from rodents, the focus has now shifted to the isolation and development of fully human antibodies. By retroviral transduction of B cell lymphoma-6 (BCL-6), which prevents terminal differentiation of B cells and, the anti-apoptotic gene B-cell lymphoma-extra large (Bcl-xL) into primary human B cells we efficiently immortalize antibody-producing B cells allowing the isolation of therapeutic antibodies. Selection of antigen-specific B cell clones was greatly facilitated because the transduced B cells retain surface immunoglobulin expression and secrete immunoglobulin into the culture supernatant. Surface immunoglobulin expression can be utilized to stain and isolate antigen specific B cell clones with labeled antigen. Immunoglobulins secreted in culture supernatant can directly be tested in functional assays to identify unique B cell clones. Here we describe the key features of our Bcl-6/Bcl-xL culture platform (AIMSelect).