[10a-S402-1~13] 12.7 Biomedical Engineering and Biochips

▲ [10a-S402-3] Monitoring T-cell Exhaustion and Immune Response at Single Cell Resolution

〇Jonathan Briones^1,3, Wilfred Espulgar^1,2, Shohei Koyama¹, Hyota Takamatsu¹, Eiichi Tamiya^2,3, Masato Saito^1,3 (1.Osaka University, 2.AIST PhotoBIO-OIL, 3.ISIR, Osaka Univ.)

Keywords:Microfluidics, Single Cell Analysis, Immunotherapy

Single-cell analysis platforms, particularly microfluidic platforms, have shown significant advantages over bulk measurements to achieve a deeper understanding of the immune mechanisms. For instance, single cell evaluation of the immune cell activities can reveal information like a state of dysfunction or T-cell exhaustion, which could have been missed by the averaging of population results in conventional bulk methods. Since programmed death receptor-1 (PD-1) expression on the cell’s surface is correlated with the exhaustion state, profiling PD-1 expressing cells and monitoring its immune activity like Granzyme B (GrB) production, is important to clinicians and researchers. Also, immune response to cancer treatment drugs (i.e. Nivolumab) can be monitored by profiling the cells with antibody blocked PD-1 receptors. Here, the profile generated can provide a wider view into the patient’s potential response to the treatment and pinpoint special cells with overexpression.
In this work, we developed a high-throughput valve-based microfluidic platform for single cell GrB activity assay. The GrB production per cell was measured fluorometrically with the cleavage of a peptide substrate containing the GrB recognition sequence (Ac-IEPD-AFC) and AFC label. Immunostaining was performed to human PBMC cells (healthy and patient) to identify cell type, PD-1 expression, and binding of IgG4 antibody. The cells’ activity profiles were generated to reveal information on the cell state, its GrB activity, and response to immunotherapy.