Principal Scientist, Biology

xairatherapeutics; South San Francisco (CA); On-site; USD 164,000 - 205,000; Full time

Job summary

Xaira Therapeutics in the Bay Area is seeking a lab-based Principal Scientist in Inflammation and Immunology to drive program strategy and set scientific direction for therapeutic programs. You will lead cross-functional collaborations and remain hands-on with disease biology and target validation.

You will design, execute, and troubleshoot key experiments, establish human and mouse primary cell cultures, and mentor junior scientists while contributing to senior leadership decisions and

Qualifications

• PhD in Immunology or related field with 6+ years of relevant experience.
• First-author publications/posters/presentations demonstrate impact.
• Ability to define research strategy and oversee complex experiments.
• Experience generating and advancing novel target hypotheses.

Responsibilities

• Define research priorities, oversee in vitro and in vivo studies, guide disease biology and lead candidate development.
• Generate and advance new biology target ideas and therapeutic strategies.
• Identify knowledge gaps and shape experimental strategy across workstreams.
• Translate data into insights and present recommendations to senior leadership.
• Stay hands-on at the bench designing, executing, and troubleshooting key experiments.
• Establish primary cell cultures from human and mouse tissues for downstream assays.
• Immune profiling via high-parameter flow cytometry and platforms (ELISA, MSD, Luminex, qPCR, RNA-seq).
• Mentor junior scientists and shape best practices within the group.

Skills

Immunology

Target discovery

Flow cytometry

Single-cell RNA-seq

CRISPR/Cas9

Omics data analysis

Team leadership

AI in research

Education

PhD in Immunology

Tools

Flow cytometry

ELISA

MSD

Luminex

qPCR

RNA-seq

Job description

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.

About the Role

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.

In this role, you will set the scientific direction for one or more therapeutic programs, generate and advance new biology target ideas, and produce actionable data that moves programs forward through cross‑functional collaboration. You will also serve as a key scientific voice to senior leadership, presenting findings and recommendations that inform program and portfolio decisions.

What You'll Do

• 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 workstreams.
• 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.

What We're Looking For

• 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 workstreams in a fast‑paced environment.
• Clear, confident communicator who can distill complex data into actionable insights for senior leadership and cross‑functional partners. Proven ability to work effectively in team environments.
• Out-of-the-box thinker who brings a creative and innovative approach to identifying and validating novel targets, challenging conventional assumptions to uncover new opportunities.

Compensation

We offer a competitive compensation and benefits package, seeking to provide an open, flexible, and friendly work environment to empower employees and provide them with a platform to develop their long-term careers. A Summary of Benefits is available for all applicants. We offer a competitive package that includes base salary, bonus, and equity. The base pay range for this position is expected to be $164,000-$205,000 annually; however, the bas