Associate Director/Director, Head of Screening Assay Development Group

Job Description

TrexBio is an early stage drug discovery company focused on the development of therapeutic antibodies targeting tissue resident regulatory T cells for the treatment of autoimmune diseases. We investigate the intersection of tissue homeostasis and regulatory T cells (Treg) – master regulators of the immune system – to unlock biological insights about crucial disease pathways. Powered by our tissue-immunology expertise, next-generation data science and multi-dimensional functional assay platforms, we decode the control of Treg in diseased tissues, discover biological targets whose biology was once impossible to grasp, and translate these discoveries into transformative medicines.

The company is based in South San Francisco and thrives on a culture of fearless curiosity, radical transparency, uncompromising teamwork and an insatiable desire to learn. We believe that our diversity is the foundation of being one strong team. Come join us on our mission to revolutionize the treatment of chronic inflammatory diseases!

We are seeking a talented and highly motivated Associate Director/Director to lead the Screening Assay Development group within the Molecular and Cellular Biology Department at TrexBio. This position offers an opportunity to build a dynamic team to design and develop target specific primary screening assays which is a critical gateway for novel therapeutic antibody discovery. The incumbent will advance TRexBio in vitro screening capabilities by developing multiplexed assays including target specific receptor/ligand binding/blocking assays, flow-based phosphorylation assays, cytokine release and reporter assays across a variety of platforms including Incucyte, Luminex and the BD Fortessa. The candidate will also act as functional lead or project lead on cross-functional project teams to design, propose and execute a strategy based on target biology for early screening of antibodies with a view towards nominating candidates for downstream characterization.

Leadership, teamwork, a can-do attitude, scientific integrity and transparency are key attributes for this position. The candidate may take a lead on therapeutic programs, fueling discussions, gaining consensus, and presenting project updates to multiple audiences. Responsibilities include development of robust functional screening assays with enhanced efficiency and/or multiplexing along with the ability to summarize and contextualize data to enable informed decisions at the team level. As TRex is a growing company, there is ample opportunity for professional growth, development and exposure to all aspects of building an innovative biotech company.


  • D in Cell Biology, Immunology or a related field
  • Greater than 8 years of biopharmaceutical industry experience with at least 3 years in the area of therapeutic antibodies in autoimmune, inflammation, and/or immuno-oncology disease areas. Job title will be commensurate with experience.
  • Experience in building/managing teams with a positive leadership style
  • Extensive experience developing robust functional assays, including co-culture, flow cytometry (10+ colors) using differentially stained cell populations, proliferation, and cytotoxicity
  • Experience with FACSDiva, FlowJo, Prism, and Microsoft Office programs
  • Proven ability to collaborate in a team-oriented environment
  • Diligent, strong growth mindset with a positive “can-do” attitude to advance programs
  • Good planning and organizational skills to meet deadlines
  • Excellent written and interpersonal communication skills


  • Advance biochemical and cell based screening capabilities, including evaluating new assay technologies and reducing multiplexed assays to practice
  • Serve as core team member on cross-functional project teams representing the screening assay function
  • Design, optimize, troubleshoot and ensure execution of early stage cell based screening strategies across projects
  • Manage, mentor and grow a talented group of junior team members
  • Detail-oriented and analytical with excellent problem-solving skills

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