Available Configurations & Antibody Expression
Fusion BioLabs offers the Human IgG1 (G236A) Fc Engineering Expression Vector (AFV-19) as a single Fc-engineered heavy-chain vector or an Fc Engineering Set/Pair with a compatible human kappa (κ) or lambda (λ) light-chain expression vector.
For complete Fc-engineered IgG antibody expression, the heavy-chain expression vector must be co-transfected with a compatible light-chain expression vector containing the corresponding antibody VL sequence.
The Fc Engineering Set/Pair includes two separate plasmids (5.0 µg each), supplied individually in TE buffer.
Important: Antibody-specific VH and VL sequences must be cloned into the corresponding vectors unless explicitly supplied with pre-inserted variable regions. Purified antibody is not included.
Compatible light-chain expression vectors are also available separately in the Fusion BioLabs Antibody Expression Vector product category.
Fc Engineering Overview
The human IgG1 (G236A) Fc variant introduces a single amino acid substitution engineered to selectively increase binding affinity for the activating receptor FcγRIIa over the inhibitory receptor FcγRIIb. This modification drives macrophage-mediated antibody-dependent cellular phagocytosis (ADCP) while maintaining baseline NK cell ADCC activity and standard FcRn recycling.
Functional Profile
| Property | Effect |
|---|---|
| FcγRIIa binding (H131 & R131) | Enhanced ↑↑ (>6× affinity boost) |
| FcγRIIa / FcγRIIb ratio | Substantially Increased ↑↑↑ (Selective activation) |
| ADCP (Phagocytosis) | Strongly Enhanced ↑↑↑ (Macrophage-Dominant) |
| FcγRIIIa binding / ADCC | Moderate / WT Baseline |
| CDC | WT Baseline to Mild Reduction |
| FcRn binding & half-life | Normal / WT Baseline |
| Effector Potency | Selective ADCP-Dominant (High FcγRIIa/FcγRIIb selectivity) |
Mechanism of Action
The G236A variant replaces glycine at position 236 in the lower hinge region of the CH2 domain with alanine (Gly236 to Ala):
- G236A Substitution: Restricts local polypeptide backbone flexibility and introduces favorable hydrophobic interactions specifically tuned to the binding pocket of activating FcγRIIa.
G236A enhances affinity for FcγRIIa without a proportional increase in binding to the structurally homologous inhibitory receptor FcγRIIb, significantly elevating the activating-to-inhibitory (A/I) ratio.
Phenotypic Effects
- Selective enhancement of macrophage and neutrophil recruitment for tumor cell phagocytosis (ADCP).
- Significantly improves the FcγRIIa/FcγRIIb binding ratio to overcome inhibitory signaling on myeloid cells.
- Preserves standard FcRn-mediated recycling and systemic pharmacokinetics.
- Distinguishes ADCP-driven clearance pathways from purely NK cell-mediated ADCC.
Applications
- Therapeutic antibodies targeting solid tumors where myeloid/macrophage infiltration dominates over NK cells.
- Macrophage-checkpoint target depletion requiring pure phagocytic enhancement without excessive NK cell hyperactivation.
- Dissecting cellular effector mechanisms (ADCP vs. ADCC) in preclinical models.
Plasmid Map & Feature Annotation
Human IgG1 (G236A)
Insert Structure: VH – CH1 – hinge – CH2(G236A) – CH3
- VH: Variable heavy domain
- CH1: Constant heavy 1
- Hinge: Native IgG1 hinge
- CH2 (G236A): Selective ADCP-enhancing single mutation
- CH3: Native IgG1 CH3 domain
Fusion BioLabs ADCC/ADCP-Enhanced Family Comparison Matrix
| Variant | Mechanism | Enhancement Strength | Primary Application & Notes |
|---|---|---|---|
| human IgG1 (WT) Wild-Type |
Native baseline FcγR binding | ★★☆☆☆ | Baseline Control. Standard physiological FcγR binding and ADCC/ADCP baseline for comparative assays. |
| human IgG1 (G236A) G236A |
Lower hinge FcγRIIa selective optimization | ★★★☆☆+ | This Product. Selective ADCP Enhancer. Specifically boosts macrophage phagocytosis by maximizing the FcγRIIa/FcγRIIb activation ratio. |
| human IgG1 (DE) S239D / I332E |
CH2 domain electrostatic interface enhancement | ★★★☆☆ | Moderate ADCC/ADCP Enhancer. Core double mutation boosting FcγRIIIa and FcγRIIa engagement. |
| human IgG1 (DLE) S239D / A330L / I332E |
CH2 domain structural interface enhancement | ★★★★☆ | Strong ADCC Enhancer. Classic triple mutation optimizing NK cell-mediated lysis. |
| human IgG1 (ADE) G236A / S239D / I332E |
CH2 domain multi-residue FcγRIIIa optimization | ★★★★☆+ | High-Potency ADCC/ADCP Enhancer. Increases FcγRIIIa binding while improving the FcγRIIa/FcγRIIb binding ratio to favor activation over inhibition. |
| human IgG1 (GASDALIE) G236A / S239D / A330L / I332E |
CH2 domain hyper-enhancement (FcγRIIIa & FcγRIIa) | ★★★★★ | Ultra-Potent ADCC/ADCP Enhancer. Maximum engineered affinity variant for low antigen density targets. |
Storage & Handling
- Store plasmid at −20°C.
- Avoid repeated freeze–thaw cycles.
- Use sterile technique when handling.
- Suitable for transient or stable mammalian expression.
References
- Yamane-Ohnuki N, Satoh M. Production of therapeutic antibodies with controlled fucosylation. MAbs. 2009;1(3):230-236.
- Richards JO, Karki S, Lazar GA, Chen H, Dang W, Desjarlais JR. Optimization of antibody binding to FcgammaRIIa enhances macrophage phagocytosis of tumor cells. Mol Cancer Ther. 2008;7(8):2517-2527.
