Principal Scientist, Biology

About Xaira Therapeutics

Xaira is an innovative biotech startup focused on leveraging AI to transform drug discovery and development. The company is leading the development of generative AI models to design protein and antibody therapeutics, enabling the creation of medicines against historically hard-to-drug molecular targets. It is also developing foundation models for biology and disease to enable better target elucidation and patient stratification. Collectively, these technologies aim to continually enable the identification of novel therapies and to improve success in drug development.

Xaira is headquartered in the San Francisco Bay Area, Seattle, and London.

Xaira Therapeutics is seeking a lab-based Principal Scientist in Inflammation and Immunology to join our Biology & Pharmacology department. This role is ideal for someone who combines hands‑on research expertise with strategic program leadership, has experience working with primary human and mouse immune cells, including ex vivo tissue systems, and is excited to shape and drive therapeutic program strategy.

• Drive program strategy by defining research priorities, designing and overseeing in vitro and in vivo studies, and guiding decisions on disease biology, target validation, and lead candidate development.
• Generate and advance new biology target ideas by evaluating novel targets and therapeutic strategies and building the scientific rationale to move them into active programs.
• Identify knowledge gaps, ask critical mechanistic questions to guide program direction, and shape experimental strategy across multiple work streams.
• Translate experimental data into actionable insights and present findings and recommendations to senior leadership and cross‑functional teams to inform program strategy.
• Stay hands‑on at the bench, personally designing, executing, and troubleshooting key experiments, particularly for high‑priority or technically challenging studies where direct expertise is needed to move a program forward.
• Establish primary cell cultures from human and mouse tissues to support downstream functional and phenotypic characterization assays, including:
  • Immune profiling - via high‑parameter flow cytometry (15+ colors) and complementary molecular platforms (ELISA, MSD, Luminex, qPCR, RNA‑seq)
  • Functional assays - including antigen presentation, immune cell activation, differentiation, proliferation, suppression, and migration
• Serve as a scientific leader and mentor within the department, contributing to the technical development of junior scientists and shaping best practices across the group, while continuing to model strong hands‑on lab practice.

• PhD in Immunology or a related field with 6+ years of relevant experience.
• Track record of impact through first‑author publications, posters, and presentations at meetings
• Demonstrated ability to independently define research strategy, plan and oversee complex experiments, and interpret data to guide program direction.
• Experience generating and advancing novel target hypotheses, with the scientific judgment to prioritize among competing ideas.
• Strong expertise in in vitro and ex vivo immunology, including primary immune assays, co‑culture systems, target cell depletion assays, and high‑parameter flow cytometry.
• Single‑cell RNA sequencing (scRNAseq), CRISPR/Cas9, and omics data analysis experience is a plus
• Proven ability to independently plan, execute, troubleshoot, and interpret experiments.
• Comfortable and enthusiastic about leveraging AI tools to support research design, data analysis, and daily workflows
• Highly organized and precise in record keeping, with the ability to manage multiple work streams in a fast‑paced environment.
• Clear, confident…