Biology subjects

Umana, P.

Publications and source records attributed to Umana, P..

3 recordsLinked to original sources

bioRxiv2025

Chronic Antigen Stimulation in Solid Tumors Induces T Cell Exhaustion and Limits Efficacy of T Cell Bispecific Therapies

T cell bispecific antibodies (TCBs) have demonstrated promising results in patients with solid tumors. However, the underlying immunological and molecular mechanisms influencing these clinical outcomes require in depth evaluation. T cell exhaustion, a state induced by prolonged antigen exposure, is known to undermine T cell-based immunotherapies, though its specific impact on TCB efficacy remains unclear. In this study, we assessed the effectiveness of TCBs on tumor-specific T cells, focusing on their functional status. Utilizing a fully immunocompetent mouse model with a solid tumor expressing an immunogenic antigen, we showed that tumor-specific T cells acquire an exhausted phenotype and fail to expand under TCB treatment. By employing both mouse and human tumor-specific T cells in vitro, our study established that chronically stimulated tumor-specific T cells show impaired response to TCB treatment. The comparison of TCB efficacy in T cell-inflamed tumors with immunogenic antigens versus non-inflamed tumors with low antigen presence in mice revealed TCB success in solid tumors is more reliant on T cell functional fitness than on their abundance before treatment. The data also indicate that solid tumors with elevated levels of both, intratumoral regulatory T cells, and T cells expressing co-inhibitory receptors, show diminished responses to TCB therapy, aligning with similar observations described in hematological cancers. These findings highlight the critical role of T cell exhaustion due to chronic antigen exposure and illustrate that exhausted tumor-specific T cells are likely not the driver population redirected by TCBs for tumor elimination. Our research highlights the importance of maintaining T cell fitness and preventing T cell exhaustion to improve TCB therapy outcomes. This may help better identify patient populations with solid tumors that could benefit from TCB treatments most in clinical settings.

cancer biology↗

bioRxiv2022

ROCKETS - a novel one-for-all toolbox for light sheet microscopy in drug discovery

Advancing novel immunotherapy strategies requires refined tools in preclinical research to thoroughly assess drug targets, biodistribution, safety, and efficacy. Light sheet fluorescence microscopy (LSFM) offers unprecedented fast volumetric ex vivo imaging of large tissue samples in high resolution. Yet, to date laborious and unstandardized tissue processing procedures have limited throughput and broader applications in immunological research. Therefore, we have developed a simple and harmonized protocol for processing, clearing and imaging of all mouse organs and even entire mouse bodies. Applying this Rapid Optical Clearing Kit for Enhanced Tissue Scanning (ROCKETS) in combination with LSFM allowed us to comprehensively study the in vivo biodistribution of an antibody targeting Epithelial Cell Adhesion Molecule (EpCAM) in 3D. Quantitative high-resolution scans of whole organs did not only reveal known EpCAM expression patterns but, importantly, uncovered several new EpCAM-binding sites. We identified choroid plexi in the brain and duodenal papillae as unexpected locations of high EpCAM-expression. These tissue locations may be considered as particularly sensitive sites due their importance for liquor production or as critical junctions draining bile and digestive pancreatic enzymes into the small bowel, respectively. These newly gained insights appear highly relevant for clinical translation of EpCAM-addressing immunotherapies. Thus, ROCKETS in combination with LSFM may help to set new standards for preclinical evaluation of immunotherapeutic strategies. Conclusively, we propose ROCKETS as an ideal platform for a broader application of LSFM in immunological research optimally suited for quantitative co-localization studies of immunotherapeutic drugs and defined cell populations in the microanatomical context of organs or even whole mice.

pharmacology and toxicology↗

bioRxiv2020

Cross-Linking of T cell to B cell lymphoma by the T cell bispecific antibody CD20-TCB induces IFNγ/CXCL10-dependent peripheral T cell recruitment in humanized murine model.

Diffuse large B cell lymphomas (DLBCL) are a highly heterogeneous subtype of Non Hodgkin Lymphoma (NHL), accounting for about 25% of NHL [1]. Despite an increased progression-free survival upon therapy, 40-50% of patients develop relapse/refractory disease, therefore there remains an important medical need [2]. T cell recruiting therapies, such as the CD20xCD3 T cell bi-specific antibody CD20-TCB (RG6026 or glofitamab), represent a novel approach to target all stages of DLBCL, especially those that fail to respond to multiple lines of treatment [3, 4]. We aimed for a better understanding of the molecular features related to the mode of action (MoA) of CD20-TCB in inducing Target/T cell synapse formation and human T cell recruitment to the tumor. To directly evaluate the correlation between synapse, cytokine production and anti-tumor efficacy using CD20-TCB, we developed an innovative preclinical human DLBCL in vivo model that allowed tracking in vivo human T cell dynamics by multiphoton intravital microscopy (MP-IVM). By ex vivo and in vivo approaches, we revealed that CD20-TCB is inducing strong and stable synapses between human T cell and tumor cells, which are dependent on the dose of CD20-TCB and on LFA-1 activity but not on FAS-L. Moreover, despite CD20-TCB being a large molecule (194.342 kDa), we observed that intra-tumor CD20-TCB-mediated human T cell-tumor cell synapses occur within 1 hour upon CD20-TCB administration. These tight interactions, observed for at least 72 hours post TCB administration, result in tumor cell cytotoxicity, resident T cell proliferation and peripheral blood T cell recruitment into tumor. By blocking the IFN{gamma}-CXCL10 axis, the recruitment of peripheral T cells was abrogated, partially affecting the efficacy of CD20-TCB treatment which rely only on resident T cell proliferation. Altogether these data reveal that CD20-TCBs anti-tumor activity relies on a triple effect: i) fast formation of stable T cell-tumor cell synapses which induce tumor cytotoxicity and cytokine production, ii) resident T cell proliferation and iii) recruitment of fresh peripheral T cells to the tumor core to allow a positive enhancement of the anti-tumor effect.

immunology↗