Senior Scientist, Immunology - Targeted LNP Delivery

    About Tr1X Tr1X is a clinical-stage biotechnology company developing engineered Tr1 cell therapies to restore immune balance in autoimmune and inflammatory diseases. Leveraging the unique biology of Tr1 cells, the company is advancing a pipeline of off-the-shelf allogeneic and in vivo CAR-Tr1 therapies designed to deliver targeted immunoregulation and address diseases driven by immune dysfunction, including transplant-related complications.

Founded by pioneers in the discovery of Tr1 cells, Tr1X, Inc. is focused on developing durable, potentially curative therapies for conditions with high unmet need. For more information, visit www.tr1x.bio. Position Summary The Senior Scientist, In vivo Immunology – Targeted LNP Delivery is an experienced, hands-on immunologist who leads the biological design and evaluation of targeted lipid nanoparticle (tLNP) formulations supporting the Tr1X in vivo chimeric antigen receptor (CAR)-Treg platform.

Reporting to the Executive Director of Biology, this individual plays a central R&D role in advancing tLNP delivery systems — defining the immunological targeting rationale and driving in vitro and in vivo proof-of-concept studies — to enable precise, immune cell-specific delivery of nucleic acid payloads. This is a high-impact, science-driven role focused on the discovery and development of Tr1X’s next-generation tLNP delivery platform.

The Senior Scientist brings deep expertise in immunology, particularly T cell and Treg biology, hands-on experience applying tLNPs in immune cells, strong experimental rigor across in vitro and in vivo studies, and the ability to thrive in a fast-paced startup environment. Key Responsibilities Partner with formulation and chemistry colleagues on the design and optimization of targeted lipid nanoparticle (tLNP) formulations for mRNA payloads, owning the immunological targeting criteria and biological evaluation.

Design and execute in vitro and in vivo studies, including humanized models, to evaluate tLNP targeting specificity to defined immune cell subsets, biodistribution, potency, and functional delivery of payload within the Tr1X in vivo CAR-Treg platform. Design and apply multiparameter flow cytometry and immunophenotyping assays to characterize tLNP uptake across immune cell subsets, targeting specificity, and downstream functional readouts such as transgene expression and suppressive activity.

Develop and apply analytical characterization methods (e.g., DLS, encapsulation efficiency, fluorescence-based assays) as needed to support formulation and conjugation research. Interpret analytical, in vitro, and in vivo data to establish structure-function relationships between tLNP formulation/conjugation attributes and biological performance. Collaborate closely with platform biology, in vivo pharmacology, and process development colleagues to advance candidate tLNP formulations from discovery through early development, and to inform downstream manufacturability considerations.

Prepare study reports, presentations, and technical documentation summarizing research findings for internal stakeholders. Stay current with emerging science in immune cell-targeted LNP delivery, Treg and lymphocyte biology, and nucleic acid therapeutics, and contribute new ideas to platform strategy. Perform other responsibilities as required based on business needs. Required Qualifications & Experience Ph.D.

in Immunology or a closely related discipline, with 4+ years of relevant industry experience. Direct, hands-on immunology research experience is required. Demonstrated hands-on experience applying targeted lipid nanoparticles (tLNPs) for cell-specific delivery to immune cells, including design of targeting strategies and evaluation of delivery in primary cells. Working familiarity with LNP formulation for mRNA or other nucleic acid payloads sufficient to collaborate effectively with formulation scientists.

Strong understanding of immunology, with specific experienc