Antibody production

Technician/Engineer, Antibody production & Molecular Biology

Valerio Tx is an innovative biotech company specializing in the development of next-generation therapeutics, such as single-domain antibodies (sdAbs) and siRNA-antibody conjugates. Our agile and passionate R&D team works on cutting-edge projects in immunology, oncology, and rare diseases.

Job Summary

Due to our diversified pipeline and growing need to produce sdAbs, we are seeking a motivated laboratory technician or engineer with expertise in recombinant protein production, preferably in yeast expression systems such as
Saccharomyces cerevisiae
(
S. cerevisiae
) and
Pichia pastoris
(
P. pastoris)
.

The desired profile is that of a
protein production expert with solid expertise in protein purification, and a mastery of methods for the
analysis of small-scale batches of sdAbs
and related molecules.

This role is central to qualifying our early therapeutic candidates issued from synthetic phage display libraries, and requires strong experimental rigor, autonomy, and the ability to work collaboratively in a dynamic biotech environment. The role reports directly to the
Director, Early CMC.

Work location
: Paris (15th district), then PSCC - Villejuif (from March 2026)

Contract:
Full-time permanent position

Key responsabilities :

The candidate's main role will be to support our internal antibody pipeline in two important areas, namely:

• The production and purification of sdAbs from Pichia pastoris supernatants
• The characterization of our candidate molecules using an array of biochemical and biophysical techniques,
  to gain insight into their affinities to the protein targets, batch purity, sources of heterogeneity (post-translational modifications) and stability. The array of analytical techniques used to characterize our molecules includes HPLC/UPLC, BLI/SPR, HTRF, SDS-PAGE, IEF and DLS.
• The goal is to provide experimental data to guarantee the developability of our lead candidates.

Missions of the role

Protein expression and analytical control

• Develop the protein production and purification platform.
• Produce and purify proteins of different type and complexity (sdAbs, VHH-Fc fusions, scFvs and different mutispecific antibody formats).
• Determine protein batch quality in accordance with internal company standards
• Participate in the implementation of internal quality standards.
• Participate in the proper use and maintenance of all the laboratory equipment dedicated to the production, purification and analytical control (incubators, AKTA protein purification systems, UPLC/HPLC, BLI…).
• Participate in the design and optimization of new molecules.
• Identify, optimize, and validate active molecules using the most appropriate biophysical assays.
• Ensure the monitoring of new technologies in your field of activity.
• Drafting internal documents (SOPs, analysis templates) to ensure the traceability of all the protein batches produced and analysed internally.
• Acting as reference for all of the above activities within the Early CMC/Lead Identification Team.

Molecular Biology

• Preparation of plasmids for protein expression: subcloning of sdAbs from phagemid vectors into optimized plasmids for yeast expression.

Data collection, analysis & reporting

• Ensure rigorous data recording following internal quality standards (ELN, SOPs).
• Analyze and interpret experimental results, present data to project teams.
• Contribute to the troubleshooting and optimization of experimental workflows in place.

Cross-functional collaborations

• Work closely with our Phage Display and Chemistry teams to support the evolution and progression of our projects.

Cellular Biology

• Some previous experience in conducting cell-based assays would be a plus. For example, cellular binding assays by flow cytometry (FACS) or FACS-based antibody internalization assays.

Qualifications & experience required

• Bachelor or Master's degree (BTS, DUT, Licence, Master, or equivalent) in Cell Biology, Molecular Biology, Biotechnology, or a related field.
• ≥7 years of laboratory experience in biotech, pharma, or academic research (industry experience preferred).
• Strong background in molecular biology, yeast metabolism, biochemical engineering or related disciplines.
• Strong expertise in protein purification is required, preferably using yeast as expression system.
• Strong practical experience in molecular biology, biochemistry and microbiology.
• Familiarity with early CMC workflows and lead evaluation.
• Expertise in cell culture and good aseptic techniques.
• Excellent organizational skills, autonomy, and ability to manage multiple experiments in parallel.
• Strong analytical mindset, attention to detail, and rigorous documentation.
• Ability to work effectively in a multidisciplinary, fast-paced environment.
• Excellent skills in spoken and written English, an organized approach with strong attention to detail and good communication skills with ability to work well in teams.
• Hands-on experience with flow cytometry (FACS) for cellular binding assays is a plus.
• Strong experience with RNA extraction, RT-qPCR, and quantitative data analysis is a plus.

Our Values :

• Scientific curiosity
  : Ability to explore complex topics with a proactive, solution-oriented mindset and strong problem-solving skills.
• Rigor and analytical mindset
  : Methodical approach, critical thinking when interpreting experimental data, with strong attention to detail and reproducibility.
• Team spirit:
  Close collaboration with R&D teams, respect for complementary expertise, and clear, constructive communication.
• Scientific integrity:
  Adherence to protocols, transparency in results, and a strong ethical commitment throughout the project.
• Adaptability
  : Agility in a fast-evolving environment, ability to handle unexpected challenges, and continuous learning from both successes and failures.
• Passionate
  about translating science into impact for patients

Why join us?

• Salary: 38K – 45K depending on profile
• Annual individual performance bonus
• 100% coverage of Vélib bike subscription
• 60% coverage of family health insurance plan
• Exciting, high-impact scientific projects
• Supportive and dynamic work environment
• Small, agile team with real responsibilities from day one