August, 2025
August 2025
M T W T F S S
 123
45678910
11121314151617
18192021222324
25262728293031
Why Drug Developers Choose IgG4 for Monoclonal Antibodies? – Illiasul Ibad
Aug 24, 2025, 08:45

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.”

Monoclonal antibodies

 

Stay updated with Hemostasis Today.