mAbsolve Fc Silencing Technology

Fc-mediated immune effector functions are an important part of an antibody’s natural function, but in many therapeutic antibodies, these interactions are not desirable and can lead to catastrophic side effects. Many approaches to eliminate effector function have been developed, but none completely silence the unwanted binding to Fc gamma receptors, except for one. The STR Fc silencing platform, developed by mAbsolve and former Absolute Antibody scientists, delivers the only truly silent Fc mutations described to date. The technology therefore has the potential to improve the safety and efficacy of therapeutic antibodies and Fc fusion proteins.

  • Comprises 3 mutations in the Fc domain
  • Can be applied to any IgG based antibody or other Fc-fusion protein
  • STR retains all the favorable attributes of an Fc domain, except for Fc receptor and C1q binding


Binding of IgG1 variants to human FcyRI (CD64). STR is the first variant to completely eliminate binding to all Fc receptors, including FcyRI.

Additional information available in the PLOS One research article “Fc-engineered antibodies with immune effector functions completely abolished.”

Benefits of producing STR-modified recombinant antibodies with Absolute Antibody

  • Scientific advisors involved in STR technology development
  • Off-the-shelf reference antibodies and isotype controls available for purchase
  • Access to a research license for early-stage therapeutic development without an ongoing fee
  • Technical support from the mAbsolve and Absolute Antibody teams
  • Industry-leading recombinant antibody engineering services

Off-the-shelf STR silenced antibodies

Product CodeProductSpecies ReactivityIsotype/Format
Ab00103-10.139Anti-erbB-2 (Her-2/neu) [4D5-8 (trastuzumab)]HumanHuman IgG1-STR
Ab00126-10.139Anti-CD20 [10F381 (rituximab)]Human, Rhesus Monkey, Cynomolgus MonkeyHuman IgG1-STR
Ab00102-10.139Anti-Fluorescein [4-4-20 (enhanced)]n/aHuman IgG1-STR
Ab00104-10.139Anti-hapten 4-hydroxy-3-nitrophenyl acetyl (NP) [B1-8]n/aHuman IgG1-STR


Interested in more information about Fc silencing? Check out our latest blog post: Is Fc Silencing Right for Your Antibody?