Screening for tumor-specific antibodies by yeast display of native repertoires of tumor-infiltrating B cells

Tumors are neoplasms that can be recognized by a patient’s immune system. Recognition of tumor antigens (TAs) triggers the recruitment and proliferation of tumor-infiltrating lymphocytes. Although tumor-infiltrating T cells have long been the primary focus of research, B cells also accumulate in tumors and participate actively in TA recognition. The use of molecular display technologies for the functional profiling of tumor-infiltrating B cell (TIB) repertoires enables large-scale screening for TAs and identification of unique TIB clones that mediate selective tumor recognition. Approaches combining microfluidic technologies for reconstructing natural TIB repertoires with yeast display were used in this study to identify antibodies that recognize TAs. It has been shown that nonspecific adhesion of yeast cells to the surface of primary tumor cell cultures from patients may be a key factor hindering the isolation of tumor-specific clones. Overcoming nonspecific binding of yeast cells enables the selection of tumor-specific clones by biopanning. Clone 3.15, isolated from the TIB repertoire of a colorectal cancer (CRC) patient, recognizes TAs on the surface of a number of tumor cell lines, as well as on primary tumor cell cultures from CRC patients. We suggest that the further use of these technologies will not only expand the diversity of molecular tools for targeted immunotherapy and tumor diagnostics but will also provide a more detailed understanding of the molecular mechanisms underlying the generation and recognition of TAs.