Arcellx, Inc. ( is a clinical-stage biotechnology company reimagining cell therapy by engineering innovative immunotherapies for patients with cancer and other incurable diseases. Arcellx believes that cell therapies are one of the forward pillars of medicine and our mission is to advance humanity by developing cell therapies that are safer, more effective, and more broadly accessible. Our offices are located in Gaithersburg, Maryland, and Redwood City, California.

Arcellx's lead product candidate, CART-ddBCMA, is being developed for the treatment of relapsed or refractory multiple myeloma (r/r MM) in an ongoing study. CART-ddBCMA has been granted Fast Track, Orphan Drug, and Regenerative Medicine Advanced Therapy designations by the U.S. Food and Drug Administration.

Arcellx is also advancing its dosable and controllable CAR-T therapy, ARC-SparX, through two programs: ACLX-001 for r/r MM and ACLX-002 in relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndrome.

We are seeking scientists to collaborate in the innovation, discovery and development of protein and cell-based therapies. The successful candidate will work closely with a dedicated team of protein engineers and more broadly with scientists in other groups (e.g. immunology, translation and manufacturing) to identify, produce, characterize and optimize recombinant proteins for use as therapeutic agents in a variety of oncology indications. We are looking for someone who brings expertise in protein engineering, as well as a strong track record of innovation and creativity.

At Arcellx, we value passion, curiosity, determination, and diversity, and look for candidates who demonstrate a genuine interest in our mission and alignment with our values.  

Key Responsibilities: 

Responsibilities will depend, in part, on hiring level, but are likely to include some or all of the following:

  • Collaborate with other scientists to design, generate and characterize recombinant proteins, including biopharmaceutical products.
  • Develop and execute selection and screening strategies using phage, yeast and mammalian display.
  • Evaluate existing and emerging technologies, techniques and tools to enhance products and streamline discovery workflows.
  • Independently plan, design, execute, record, and analyze experiments.
  • Summarize and present data in internal meetings and discussions.
  • Write and review technical protocols and reports. Coauthor scientific abstracts, manuscripts and presentations.
  • Manage and drive the advancement of internal projects, products or technology initiatives.


Preferred qualification will depend, in part, on hiring level, but are likely to include some or all of the following:

  • PhD in the life sciences (e.g. biochemistry, chemistry, chemical engineering, biology, immuno-oncology), with a minimum of 2 years post-degree experience in protein engineering.
  • Extensive experience in the design, construction, expression, characterization, and optimization of recombinant proteins.
  • Experience with biopharmaceutical product design and lead optimization is ideal.
  • Experience in the design and execution of selection and screening strategies, utilizing phage display (or a related display method).
  • Proficiency with high throughput screening, sequencing and characterization of bacterial clones.
  • Experience with optimizing expression yield and quality. Experience with multiple protein expression systems (e.g. bacterial, yeast or mammalian systems) is preferred.
  • Experience utilizing and developing appropriate methods for assessment of protein-protein interactions (e.g. ELISA, Octet BLI, Biacore SPR, MSD)
  • Experience with sequence analysis software (e.g. SnapGene, Sequencher, Lasergene, BLAST, etc.), including construct and primer design and sequence confirmation.
  • Programming experience with Python and/or R (R Studio) is ideal.
  • Experience in oncology, immunology, and translational research is ideal.


  • Has character and integrity. Committed to always doing what’s right.
  • Self-motivated and able to work autonomously. Can produce top-quality work with little oversight.
  • "No job is too small" mentality. Humble and willing to help others.
  • Able to build strong relationships and collaborate effectively with colleagues.
  • Gives direct, candid, and respectful feedback. Can receive feedback with curiosity and without getting defensive.
  • Always looking to improve and challenge the status quo. Gritty and determined.

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