Immunity & infection
Despite the advent of direct-acting antiviral therapies, infection rates for Hepatitis C Virus (HCV) remain high and a vaccine remains necessary to reduce infections rates. Although it is known that a diverse CD8+ T cell response is needed to clear acute HCV infection in the liver, human studies at the HCV-infected liver:T cell interface remain challenging. Here, we present a method to coculture human HLA-matched HCV-specific T cells with human liver organoids infected with HCV. We show by light sheet microscopy that class I HLA is expressed on the external surface of liver organoids, at comparable levels between HCV+ and HCV- donors. While liver organoids are exquisitely sensitive to media containing FBS, we find that T cell clones retain their viability and cytolytic capacity in organoid media for up to five days. To monitor T cell:organoid interactions, the two cell systems were co-cultured in a specific microfluidic chip (Roger Kamm) that allows for tractable migration of T cells into the organoid-containing matrigel. The system was then analyzed within the chip by quantitative microscopy or after removal by flow cytometry. We find that loading surface HLA with specific HCV peptides induced T cells to express cytolytic cytokines and caused highly reproducible cytolysis of the organoids. We are currently performing experiments with HCV-infected organoids and autologous T cells, the results of which will be discussed. We propose that this coculture system presents a new way to study HCV antigenicity, T cell specificity and the immunotolerant liver environment in a highly tractable manner.