Mechanism of EBV inducing anti-tumour immunity and its therapeutic use

Tumour-associated antigens (TAAs) comprise a large collection of non-mutated cellular antigens recognized by T cells in human and murine cancers. Their potential as immunotherapy targets has been explored for over two decades(1), yet the genesis of TAA-specific T cells remains elusive. While tumour cells may be an important source of TAAs for T cell priming(2), several recent studies suggest that infection with some viruses including Epstein-Barr virus (EBV) and influenza virus can elicit T cell responses against abnormally expressed cellular antigens that function as TAAs(3,4). However, the cellular and molecular basis of such responses remains undefined. Here, we show that expression of the EBV signaling protein LMP1 in B cells provokes T cell responses to multiple TAAs. LMP1 signaling leads to overexpression of many cellular antigens previously shown to be TAAs, their presentation on MHC-I and -II (mainly through the endogenous pathway), and the upregulation of costimulatory ligands CD70 and OX40L, thereby inducing potent cytotoxic CD4(+) and CD8(+) T cell responses. These findings delineate a novel mechanism of infection-induced anti-tumour immunity. Furthermore, by ectopically expressing LMP1 in patient tumour B cells and thereby empowering them to prime T cells, we develop a general approach for rapid production of autologous cytotoxic CD4(+) T cells against a broad array of endogenous tumour antigens, such as TAAs and neoantigens, for treating B-cell malignancies. This work stresses the need to revisit classical concepts concerning viral and tumour immunity, which will be critical to fully understand the impact of common infections on human health and to improve the rational design of immune approaches for cancers.