Why Drug Developers Choose IgG4 for Monoclonal Antibodies? – Illiasul Ibad
Illiasul Ibad, Rheumatologist at Christian Medical College, posted on X:
”1․ Why are many therapeutic monoclonal antibodies built on the IgG4 framework?
2․ Understand basics
Biology of IgG4
• Least abundant IgG subclass
• Very weak complement activation
• Poor interaction with Fc receptors → almost no ADCC
Translation: IgG4 can block targets without collateral tissue damage.
3․ Fab-arm exchange
Natural IgG4 can swap half its arms → becomes “functionally monovalent.”
Good for tolerance in nature, but bad for drug stability.
Solution: scientists engineered the S228P mutation → no swapping, molecule stays stable.
4․ Why drug developers love IgG4
• Precise blocking, not killing
• Low inflammation risk
• Engineered stability
• Safe for long-term therapy
That’s why IgG4 is the backbone of modern antibody medicines – quiet, stable, effective.”

Stay updated with Hemostasis Today.
-
Apr 15, 2026, 04:06Brenda Pleasant: Insights from the HFA Symposium on Hemophilia Care
-
Apr 15, 2026, 03:43Lexy Halloran: Addressing Diagnostic Inequities in Women with Chronic Conditions
-
Apr 14, 2026, 17:32Denise M.: Surviving Sepsis 2026 – The Upstream Revolution
-
Apr 14, 2026, 17:23Meghanath Yenni։ What’s New in Acute Ischemic Stroke in 2026
-
Apr 14, 2026, 17:11Phil Spinella: What Dose of TXA for Children With Severe Traumatic Bleeding Should You Use?
-
Apr 14, 2026, 17:08Abdulrahman Katib: How Endovascular Stenting Is Transforming the Treatment of Severe PTS
-
Apr 14, 2026, 17:00Anna A. Avagyan: Glad to Be Part of EHA Pediatric Hematology-Oncology Course
-
Apr 14, 2026, 16:58Ney Carter Borges: NLRP3 Inhibition in Atherosclerosis – Early Clinical Signal Beyond Lipids
-
Apr 14, 2026, 16:56Saskia Middeldorp: Key Takeaways from the 2026 ACC/AHA Guideline on Acute PE