Sr. Scientist I, Antibody Engineering

ModeX Therapeutics•Weston, MA

About The Position

ModeX is seeking an experienced, hands-on antibody discovery scientist to lead and execute integrated antibody discovery and engineering campaigns. The role focuses on sourcing, engineering, and selecting high-quality antibody building blocks with the binding, functional, biophysical, and developability properties needed for complex multispecific formats. The scientist will combine expertise in primary B-cell workflows with antibody engineering, including humanization, affinity and specificity optimization, sequence-liability mitigation, and structure-based design. The position collaborates with Protein Sciences, Digital Biology, Translational Science, and project teams to generate differentiated, developable binders for multispecific therapeutics in oncology and infectious disease. It also contributes to platform-building, workflow improvement, mentoring, and evidence-based project decisions. ModeX Therapeutics is an OPKO Health company developing multispecific therapeutics through its MSTAR platform. ModeX is based in Weston, Massachusetts.

Requirements

PhD in immunology, molecular biology, biochemistry, protein engineering, or a related field with 5+ years of relevant industry experience, or an MS with 8+ years of relevant industry experience.
Hands-on experience leading multiple therapeutic antibody discovery campaigns from source material through validated lead antibodies.
Deep practical expertise in primary B-cell isolation, antigen-specific B-cell sorting, single-cell antibody cloning, variable-gene recovery, and recombinant expression.
Antibody engineering experience including humanization and at least two of the following: affinity maturation, structure-based design, specificity engineering, sequence-liability remediation, or developability optimization.
Strong experience with multiparameter flow cytometry and sorting-based methods, including panel design, controls, gating strategy, operation, and troubleshooting.
Experience designing and interpreting antibody screening and characterization assays such as ELISA, BLI and/or SPR, cell-binding assays, competition or epitope-binning assays, and functional assays.
Fluency in antibody sequence analysis, clonotype and lineage assessment, CDR and framework evaluation, and data-driven candidate selection.
Ability to independently design experiments, resolve technical failures, integrate large datasets, and make sound lead-selection recommendations.
Clear scientific communication, strong documentation practices, and success working across discovery, computational, protein sciences, and translational teams.

Nice To Haves

Experience with humanized transgenic rodent platforms and/or human immune-repertoire mining.
Experience with yeast, phage, mammalian, or ribosome display for antibody discovery or optimization.
Hands-on use of single-cell discovery platforms or microfluidic workflows, such as Beacon or equivalent technologies.
Experience with NGS-enabled discovery, repertoire analytics, sequence clustering, and campaign data management.
Working knowledge of early developability assessments, including aggregation, hydrophobicity, self-interaction, thermal stability, expression, and polyspecificity risks.
Experience using structural biology, molecular modeling, or AI/ML-supported tools to guide antibody design, with evidence of experimental validation.
Experience engineering antibodies for bispecific, trispecific, T-cell engager, or other multispecific formats.

Responsibilities

Lead and execute end-to-end antibody discovery campaigns, from antigen and immunization strategy through B-cell isolation, antigen-specific single-cell sorting, variable-region recovery, cloning, recombinant expression, screening, and lead selection.
Design and perform primary B-cell discovery workflows using immunized rodents, including humanized transgenic animals, and apply single-cell technologies and high-throughput cloning to recover rare, diverse binders.
Engineer therapeutic antibodies through humanization, affinity maturation, specificity optimization, germline and humanness assessment, and removal of sequence or chemical liabilities while preserving function.
Apply structure-guided design using experimental structures or high-confidence models to interpret paratope–epitope interactions and guide mutagenesis and improvements in antibody properties.
Design and analyze screening cascades covering binding, competition, epitope diversity, affinity and kinetics, cell-surface binding, functional activity, and early developability.
Use flow cytometry/FACS, ELISA, BLI or SPR, and sequence analysis to characterize and rank candidates; partner with protein sciences on expression, purification, and biophysical assessment.
Convert and evaluate antibodies across IgG, Fab, scFv, bispecific, and higher-order multispecific formats, identifying format-dependent risks early.
Integrate repertoire sequencing, NGS, bioinformatics, and computational or AI-enabled tools to improve campaign design, sequence triage, clustering, and engineering decisions.
Document campaign strategy, clone lineage, sequence, assay, and selection data in Benchling or equivalent systems, and communicate recommendations at project decision points.
Mentor colleagues, troubleshoot complex workflows, manage external partners when needed, and contribute to platform-building and continuous improvement.