RNA-electroporated CD40-activated B cells induce functional T-cell responses against HepG2 cells

Hepatocellular carcinoma (HCC) is one of the incurable tumours in the world. Cell-based immunotherapy, in which antigen-loaded antigen-presenting cells (APCs) are able to elicit T cell responses, has become an alternative treatment for liver cancer. Here, we used HepG2 cells' total RNA-electroporated CD40 ligand-activated B (CD40-B) cells as alternative APC for induction of specific CD8⁺ T-cell responses. The antigen-presenting ability of CD40-B cells was determined by phenotypic analysis, showing a polyclonal, strongly activated B-cell population with high expression of co-stimulatory molecules. To demonstrate the ability of total RNA extracted from HepG2 cells electroporated CD40-B cells to induce CD8⁺ T-cell responses, these RNA-loaded cells were co-cultured with autologous peripheral blood mononuclear cells for 7 days followed by analysis of T-cell antigen specificity. These experiments showed that CD40-B cells electroporated with HepG2 cells' total RNA are capable of activating antigen-specific interferon-γ-producing CD8⁺ T cells, and these T cells activated by CD40-B cells show a killing effect on HepG2 cells. These findings demonstrated that the carcinoma cell derived total RNA-electroporated CD40-B cells could be used as alternative APC for the induction of antigen-specific CD8⁺ T-cell responses, which might be used in HCC immunotherapy.