Tu167 - Detection of Immune Repertoire and Transcriptome Changes in a Murine Tuberculosis Model with Microsampling Technology

Alex Chenchik – Cellecta, Inc.; Khadija Ghias – Cellecta, Inc.; Dongfang Hu – Cellecta, Inc.; Mikhail Makhanov – Cellecta, Inc.; Kitt Paraiso – Cellecta, Inc.; Shivraj Yabaji – Boston University; Igor Kramnik – Boston University

Abstract Text: This study introduces a novel approach in tuberculosis (TB) research using murine models, focusing on non-terminal blood sampling for immunological profiling during disease progression. Current approaches rely primarily on the evaluation of lung lesions after euthanasia, with a large number of animals needed for time-course and dose-response studies. Measuring blood biomarkers in small volumes obtained serially could provide useful insights and reduce the number of animals needed. Hence, we evaluated the utility of small-volume blood samples for profiling T- and B-cell receptor repertoires and transcriptomes in mice (n=16) at different stages of TB progression (early, middle, and advanced—defined by lung histopathology and mycobacterial loads). We isolated RNA from 100 uL of whole blood for TCR/BCR profiling using the Cellecta DriverMap™ adaptive immune receptor (AIR) assay as well as transcriptome quantitation of ~4700 key mouse genes using a targeted RNA-sequencing panel. The results showed substantial changes in clonotype usage and diversity over the course of TB disease, most prominent in the BCR IgH (e.g, top 10 clonotype abundance count in control, early, advanced disease, respectively: 62 + 47, 1792 + 589, 3559 + 286, p < .01, mean + SD, n=3-4). Blood transcriptome profiling showed abundant up-regulation of immune and inflammatory genes (e.g, up-regulated genes vs control: 182 (early), 382 (advanced), q.05 FC1.5). The results support direct testing of non-terminal serial blood samples to characterize disease progression and therapeutic or vaccine interventions.