(160y) Single Cell Microwell Immunoassay for Quantitative Immune Response Monitoring

The heterogeneity of cancer cells and complexity of immune cells among patients imperatively call for the need to quantitatively study immune efficacy at the single cell level. However, existing technologies for single immune cell analysis have a number of limitations, including simultaneous assessment of cell-cell interactions and cytokine secretion in a high-throughput platform. We report on a new single cell microwell technique that allows simultaneous control on the immune-cancer cell interaction, and the detection of secreted proteins inside microwells. As proof of concept, a surface modified microwell array has been developed to co-culture OVA-specific CD8 T cells (OT-1) with a single ovalbumin transfected B16 melanoma cell (B16-OVA) in each well. T-cell mediated cytolysis of fluorescently labeled B16-OVA cells was monitored by detecting a decrease in fluorescence intensity. Our data demonstrate that over 90% of B16-OVA cells were eliminated by OT-1 cells, and when several T cells were co-cultured with a single cancer cell, a shorter killing time was recorded. This was further confirmed by immunoassay as co-culturing more than one T-cell with a cancer cell would lead to increased cytokine secretion. This platform could be used for high-throughput analysis of immune cells, study cell-cell interactions, and screen powerful immune cells at a single cell level for personalized immunotherapy.