Principal Scientist (Cell Line Development)
Exelixis
August 22, 2026
On-site
Alameda, CA
Clinical Research and Development
SUMMARY/JOB PURPOSE:
Member of Biotherapeutics group supporting discovery and preclinical development via recombinant and bispecific antibody production, purification/characterization. Deliver high-quality CHO mammalian cell lines for early-phase biologics manufacturing (including potential ADCs). Design/test vector constructs, engineer host cells, perform transfection/selection/single-cell clone generation in CHO, and use recombinant protein expression knowledge to improve stable-cell-line titer.
ESSENTIAL DUTIES AND RESPONSIBILITIES:
- Design and execute experiments to develop CHO-based clinical biologic cell lines.
- Innovate/improve expression systems and workflows using new technologies.
- Conduct CHO cell line development: transfection, single-cell cloning, imaging analysis for monoclonality, clone screening/progression, characterization, cell banking, and stability assessment.
- Develop improved expression vectors/genetic components; optimize host cell engineering and/or cell line development processes.
- Identify emerging practices to shape strategies for continued innovation.
- Represent team on cross-functional projects; decide on cell line activities and communicate results/progress/plans.
- Comply with health & safety policies and general laboratory practices.
QUALIFICATIONS (EDUCATION/EXPERIENCE):
- BS (molecular biology/biochemistry/biology/microbiology) + 11 years biotech/pharma experience; or MS + 9 years; or PhD + 5 years; or equivalent.
REQUIRED EXPERIENCE/SKILLS:
- Proficiency in molecular biology, vector construction, and genetic elements impacting recombinant antibody/bispecific expression.
- Experience with stable CHO expression platforms; transfection methods; screening/selection workflows.
- Deep understanding of regulatory requirements for demonstrating monoclonality.
- CHO culture experience (shake flasks, spin tubes, deep-well plate fed-batch); Ambr fed-batch is a plus.
- Single-cell cloning and imaging technologies for monoclonality.
- Titer determination and downstream product quality assessments.
- Author/review cell line development reports.
PREFERRED:
- HPLC, LC/MS, and/or CE.
- Automation platforms and data analysis tools.
- Electronic lab notebook/workflow management.
- Prior recombinant antibody/bispecific study design and data-driven conclusions.
COMPENSATION/BENEFITS (as stated):
- Base pay: $150,000–$213,000 annually.
- 401(k) with company contributions; medical/dental/vision; life/disability; flexible spending; discretionary bonus (or sales incentive for field sales); stock purchase; long-term incentives; 15 vacation days (year 1); 17 paid holidays (incl. winter shutdown); up to 10 sick days.
Member of Biotherapeutics group supporting discovery and preclinical development via recombinant and bispecific antibody production, purification/characterization. Deliver high-quality CHO mammalian cell lines for early-phase biologics manufacturing (including potential ADCs). Design/test vector constructs, engineer host cells, perform transfection/selection/single-cell clone generation in CHO, and use recombinant protein expression knowledge to improve stable-cell-line titer.
ESSENTIAL DUTIES AND RESPONSIBILITIES:
- Design and execute experiments to develop CHO-based clinical biologic cell lines.
- Innovate/improve expression systems and workflows using new technologies.
- Conduct CHO cell line development: transfection, single-cell cloning, imaging analysis for monoclonality, clone screening/progression, characterization, cell banking, and stability assessment.
- Develop improved expression vectors/genetic components; optimize host cell engineering and/or cell line development processes.
- Identify emerging practices to shape strategies for continued innovation.
- Represent team on cross-functional projects; decide on cell line activities and communicate results/progress/plans.
- Comply with health & safety policies and general laboratory practices.
QUALIFICATIONS (EDUCATION/EXPERIENCE):
- BS (molecular biology/biochemistry/biology/microbiology) + 11 years biotech/pharma experience; or MS + 9 years; or PhD + 5 years; or equivalent.
REQUIRED EXPERIENCE/SKILLS:
- Proficiency in molecular biology, vector construction, and genetic elements impacting recombinant antibody/bispecific expression.
- Experience with stable CHO expression platforms; transfection methods; screening/selection workflows.
- Deep understanding of regulatory requirements for demonstrating monoclonality.
- CHO culture experience (shake flasks, spin tubes, deep-well plate fed-batch); Ambr fed-batch is a plus.
- Single-cell cloning and imaging technologies for monoclonality.
- Titer determination and downstream product quality assessments.
- Author/review cell line development reports.
PREFERRED:
- HPLC, LC/MS, and/or CE.
- Automation platforms and data analysis tools.
- Electronic lab notebook/workflow management.
- Prior recombinant antibody/bispecific study design and data-driven conclusions.
COMPENSATION/BENEFITS (as stated):
- Base pay: $150,000–$213,000 annually.
- 401(k) with company contributions; medical/dental/vision; life/disability; flexible spending; discretionary bonus (or sales incentive for field sales); stock purchase; long-term incentives; 15 vacation days (year 1); 17 paid holidays (incl. winter shutdown); up to 10 sick days.