Periodic Reporting for period 4 - FATE (Functional Biology of Hepatic CD8+ T cells)
Periodo di rendicontazione: 2022-01-01 al 2023-06-30
Problem/Issue Addressed: The intricacies of CD8+ T cell behavior within the liver, especially at the single-cell level, remain largely unexplored. These cells are vital in neutralizing intracellular pathogens and tumors in the liver. Their efficacy is hinged on their capacity to traffic within the liver, recognize antigens, activate, and manifest their effector functions.
Importance for Society: Comprehending the dynamics of intrahepatic CD8+ T cells is crucial as it offers avenues for the development of enhanced vaccination and innovative immunotherapeutic strategies, addressing infectious diseases and cancer.
Overall Objectives:
1. Understand how factors in hepatocellular carcinomas influence CD8+ T cell behavior and function.
2. Examine intrahepatic T cell priming events resulting in functionally compromised T cell responses.
Conclusions of the Action:
Aim 1: Our innovative mouse model, replicating the salient features of human hepatocellular carcinoma, revealed pivotal insights into CD8+ T cell behavior within tumors. Specifically, we discovered that the antitumor potential of these effector CD8+ T cells diminishes notably when tumor lesions grow beyond a size of 100 mm3. Our research pinpointed the causal factors: larger lesions ("non-responder lesions") presented obstacles to effective antigen recognition and subsequent T cell activation, in contrast to smaller lesions ("responder lesions"), which retained a more receptive environment. A crucial breakthrough was understanding the endothelial transformation in primary liver cancers, characterized by the shift from fenestrated liver sinusoidal endothelial cells (LSECs) to capillarized ones, fundamentally altering the immunosurveillance capabilities of CD8+ T cells. This alteration proposes the potential of reprogramming endothelial cells to improve immune responses within larger tumors, paving the way for enhanced efficacy of treatments like CAR T cells. Our research on this front is in its final stages and we're preparing to present our findings to a prestigious journal.
Aim 2: As detailed in Benechet et al., Nature 2019, and De Simone et al., Immunity 2021, we found that hepatocyte-primed T cells demonstrated unique dysfunctional attributes. This dysfunctional state, while resistant to conventional treatments like anti-PD-L1, responded to IL-2, presenting an avenue for therapeutic intervention. Collaborative efforts led to the development of a targeted IL-2 based therapeutic, uniquely activating the IL-2 pathway in CD8+ T cells, without the pleiotropic effects seen in other immune cells. The effectiveness of this approach in treating chronic HBV was underscored by its ability to significantly bolster the HBV-reactive CD8+ T cells, enhancing their antiviral activity, as evidenced in our mouse models and cynomolgus monkey studies. This therapeutic trajectory provides hope for innovative treatments targeting chronic HBV and potentially other conditions.
In conclusion, the grant facilitated pivotal advancements in our understanding of intrahepatic CD8+ T cell dynamics. Through rigorous research, we not only unveiled key behavioral patterns but also paved the way for novel therapeutic strategies. Each facet of our proposed objectives has been addressed in depth, pushing the boundaries of current scientific knowledge and setting the stage for future breakthroughs.
Importance for Society: Comprehending the dynamics of intrahepatic CD8+ T cells is crucial as it offers avenues for the development of enhanced vaccination and innovative immunotherapeutic strategies, addressing infectious diseases and cancer.
Overall Objectives:
1. Understand how factors in hepatocellular carcinomas influence CD8+ T cell behavior and function.
2. Examine intrahepatic T cell priming events resulting in functionally compromised T cell responses.
Conclusions of the Action:
Aim 1: Our innovative mouse model, replicating the salient features of human hepatocellular carcinoma, revealed pivotal insights into CD8+ T cell behavior within tumors. Specifically, we discovered that the antitumor potential of these effector CD8+ T cells diminishes notably when tumor lesions grow beyond a size of 100 mm3. Our research pinpointed the causal factors: larger lesions ("non-responder lesions") presented obstacles to effective antigen recognition and subsequent T cell activation, in contrast to smaller lesions ("responder lesions"), which retained a more receptive environment. A crucial breakthrough was understanding the endothelial transformation in primary liver cancers, characterized by the shift from fenestrated liver sinusoidal endothelial cells (LSECs) to capillarized ones, fundamentally altering the immunosurveillance capabilities of CD8+ T cells. This alteration proposes the potential of reprogramming endothelial cells to improve immune responses within larger tumors, paving the way for enhanced efficacy of treatments like CAR T cells. Our research on this front is in its final stages and we're preparing to present our findings to a prestigious journal.
Aim 2: As detailed in Benechet et al., Nature 2019, and De Simone et al., Immunity 2021, we found that hepatocyte-primed T cells demonstrated unique dysfunctional attributes. This dysfunctional state, while resistant to conventional treatments like anti-PD-L1, responded to IL-2, presenting an avenue for therapeutic intervention. Collaborative efforts led to the development of a targeted IL-2 based therapeutic, uniquely activating the IL-2 pathway in CD8+ T cells, without the pleiotropic effects seen in other immune cells. The effectiveness of this approach in treating chronic HBV was underscored by its ability to significantly bolster the HBV-reactive CD8+ T cells, enhancing their antiviral activity, as evidenced in our mouse models and cynomolgus monkey studies. This therapeutic trajectory provides hope for innovative treatments targeting chronic HBV and potentially other conditions.
In conclusion, the grant facilitated pivotal advancements in our understanding of intrahepatic CD8+ T cell dynamics. Through rigorous research, we not only unveiled key behavioral patterns but also paved the way for novel therapeutic strategies. Each facet of our proposed objectives has been addressed in depth, pushing the boundaries of current scientific knowledge and setting the stage for future breakthroughs.
Introduction: CD8+ T cells play a pivotal role in eradicating intracellular pathogens and liver tumors. Their efficacy depends on migration within the liver, recognition of pathogen or tumor antigens, activation, and subsequent deployment of effector functions. While general behaviors of these T cells in diseased livers were known at a broader level, our project sought a granular, single-cell understanding.
Aim 1: Evaluating CD8+ T Cell Behaviors in Liver Tumors: To delve into how tumors might affect CD8+ T cell function, we engineered a mouse model replicating human hepatocellular carcinoma. Our observations were stark: as tumor lesions surpassed 100 mm3, CD8+ T cell antitumor functions were notably compromised. We traced this inefficacy in larger lesions to an endothelial switch – from fenestrated liver sinusoidal endothelial cells (LSECs) to their non-fenestrated counterparts. This switch affected CD8+ T cell immune surveillance, suggesting that reprogramming these endothelial cells could amplify the immune response within larger tumors. This work is nearing completion and will soon be submitted to a leading journal.
Aim 2: Deciphering the Priming Dynamics of CD8+ T Cells: Our published findings (Benechet et al., Nature 2019) unveiled the distinct responses of CD8+ T cells based on their priming sources: Kupffer cells led to a more static, dense T cell arrangement, while hepatocyte priming resulted in a dynamic and spread-out T cell cluster formation. These hepatocyte-primed T cells showcased unique dysfunctional features, differing from traditional exhausted or tolerant T cells. Interestingly, these cells reacted positively to IL-2 treatments, and their optimal in vivo re-invigoration required Kupffer cell cross-presentation (De Simone et al., Immunity 2021).
Translational Application - CD8-IL2 Therapy: Recognizing the IL-2's potential but wary of its pleiotropic effects, we collaborated with Asher Biotherapeutics. Together, we developed CD8-IL2, a fusion protein specifically targeting CD8+ T cells. Our pre-clinical results indicated its promising potential in treating chronic HBV. In mouse models, it notably amplified the numbers and potency of HBV-reactive CD8+ T cells, reducing key HBV indicators. These results found further validation in cynomolgus monkeys, supporting CD8-IL2's therapeutic promise for chronic HBV.
Exploitation and Dissemination: The knowledge we've garnered has been foundational in filing multiple patents and securing two ERC PoCs. Collaborative endeavors with industry partners like Asher Biotherapeutics emphasize the translational potential of our findings. With a commitment to knowledge sharing, we have published our research in leading journals, ensuring our findings contribute to broader scientific understanding and potential clinical applications.
Aim 1: Evaluating CD8+ T Cell Behaviors in Liver Tumors: To delve into how tumors might affect CD8+ T cell function, we engineered a mouse model replicating human hepatocellular carcinoma. Our observations were stark: as tumor lesions surpassed 100 mm3, CD8+ T cell antitumor functions were notably compromised. We traced this inefficacy in larger lesions to an endothelial switch – from fenestrated liver sinusoidal endothelial cells (LSECs) to their non-fenestrated counterparts. This switch affected CD8+ T cell immune surveillance, suggesting that reprogramming these endothelial cells could amplify the immune response within larger tumors. This work is nearing completion and will soon be submitted to a leading journal.
Aim 2: Deciphering the Priming Dynamics of CD8+ T Cells: Our published findings (Benechet et al., Nature 2019) unveiled the distinct responses of CD8+ T cells based on their priming sources: Kupffer cells led to a more static, dense T cell arrangement, while hepatocyte priming resulted in a dynamic and spread-out T cell cluster formation. These hepatocyte-primed T cells showcased unique dysfunctional features, differing from traditional exhausted or tolerant T cells. Interestingly, these cells reacted positively to IL-2 treatments, and their optimal in vivo re-invigoration required Kupffer cell cross-presentation (De Simone et al., Immunity 2021).
Translational Application - CD8-IL2 Therapy: Recognizing the IL-2's potential but wary of its pleiotropic effects, we collaborated with Asher Biotherapeutics. Together, we developed CD8-IL2, a fusion protein specifically targeting CD8+ T cells. Our pre-clinical results indicated its promising potential in treating chronic HBV. In mouse models, it notably amplified the numbers and potency of HBV-reactive CD8+ T cells, reducing key HBV indicators. These results found further validation in cynomolgus monkeys, supporting CD8-IL2's therapeutic promise for chronic HBV.
Exploitation and Dissemination: The knowledge we've garnered has been foundational in filing multiple patents and securing two ERC PoCs. Collaborative endeavors with industry partners like Asher Biotherapeutics emphasize the translational potential of our findings. With a commitment to knowledge sharing, we have published our research in leading journals, ensuring our findings contribute to broader scientific understanding and potential clinical applications.
All results reported above represent significance advance over the state of the art. Both aims have been successfully completed.