Integration of B cell responses through Toll-like receptors and antigen receptors

B cells are unique in their ability to link the innate and adaptive immune systems owing to their expression of both an antigen-specific B cell receptor (BCR) and pattern-recognizing Toll-like receptors (TLRs). This article focuses on the role of dual BCR and TLR signalling in fine-tuning B cell responses, with a particular emphasis on B cell-intrinsic events. Unlike other immune cells, B cells express both an antigen-specific B cell receptor (BCR) and Toll-like receptors (TLRs). Dual BCR and TLR engagement can fine-tune functional B cell responses, directly linking cell-intrinsic innate and adaptive immune programmes. Although most data regarding B cell-specific functions of the TLR signalling pathway have been obtained in mice, the discovery of patients with a deficiency in this pathway has recently provided an insight into human B cell responses. Here, we highlight the importance of the integration of signalling pathways downstream of BCRs and TLRs in modulating B cell function, focusing when possible on B cell-intrinsic roles.