High resolution microfluidic assay and probabilistic modeling reveal cooperation between T cells in tumor killing

Abstract

Cytotoxic T cells are important components of natural anti-tumor immunity and are harnessed in tumor immunotherapies. Immune responses to tumors and immune therapy outcomes largely vary among individuals, but very few studies examine the contribution of intrinsic behavior of the T cells to this heterogeneity. Here we show the development of a microfluidic-based in vitro method to track the outcome of antigen-specific T cell activity on many individual cancer spheroids simultaneously at high spatiotemporal resolution, which we call Multiscale Immuno-Oncology on-Chip System (MIOCS). By combining parallel measurements of T cell behaviors and tumor fates with probabilistic modeling, we establish that the first recruited T cells initiate a positive feedback loop to accelerate further recruitment to the spheroid. We also provide evidence that cooperation between T cells on the spheroid during the killing phase facilitates tumor destruction. Thus, we propose that both T cell accumulation and killing function rely on collective behaviors rather than simply reflecting the sum of individual T cell activities, and the possibility to track many replicates of immune cell-tumor interactions with the level of detail our system provides may contribute to our understanding of immune response heterogeneity.

T cell-mediated additive cytotoxicity – death by multiple bullets

“…Similar observations of perforin pore-positive but ineffective (nonlethal) CTL-target cell pairings indicate similar multihit interactions in CD19-CAR T cells targeting mouse B cell lymphoma in vivo [18] and CTLs confronted with virally transfected target cells [12]. Furthermore, monitoring CTL killing of tumor spheroids in controlled microfluidic-based systems combined with probabilistic modeling provides evidence of cooperative killing behavior that exceeds purely additive effects of individual T cell activities [19]. Thus, CTL-induced target cell death is not a binary event but rather relies on the integration of damage frequency with damage repair efficacy in the target cell over time.…”

“…OPEN ACCESS that enhances local CTL swarming [19], possibly by chemokines produced by CTLs upon target cell recognition [54]. In addition, supramolecular attack particles, which were recently described to be deposited on tumor cells by transient CTL and NK cell contacts [55][56][57], may contribute to the additive cytotoxic effects towards target cells.…”

New insights into CAR T cell-mediated killing of tumor cells

“…IFNg receptor signaling leads to an increase in the production of CXCR3 ligands, namely CXCL9, 10 and 11 which have the potential to promote the avidity of LFA-1 on T cells as well as to attract other immune effector cells to the tumor site. In this context, Using an ex vivo 3D tumor model Ronteix et al (32) have shown that the first T cells contacting tumor cells initiated a positive feedback loop that accelerated the recruitment of other T cells to the tumor spheroid in agreement with the secretion of a T cell-attractant factor.…”

“…In this context, Using an ex vivo 3D tumor model Ronteix et al. ( 32 ) have shown that the first T cells contacting tumor cells initiated a positive feedback loop that accelerated the recruitment of other T cells to the tumor spheroid in agreement with the secretion of a T cell-attractant factor.…”

Anin vivoavian model of human melanoma to perform rapid and robust preclinical studies

“…Organoids may prove useful for high-throughput chemical screens, but they lack crucial components of the TME and have so far not been extensively validated for melanoma (Ronteix et al, 2022). Testing drug efficacy on ex vivo tumor fragments was recently shown to hold a robust predictive capacity, including for immunotherapy (Voabil et al, 2021).…”