FOXP3 Polyclonal Antibody (ABP0141): C-Terminal Epitope Targeting for Regulatory T-Cell Research
FOXP3: The Master Regulator with a Detection Problem
FOXP3 (Forkhead box protein P3) is the master transcriptional regulator of regulatory T cells (Tregs)—the subset that enforces immune tolerance and restrains autoimmunity. Defects in FOXP3 cause IPEX syndrome (immunodeficiency polyendocrinopathy, enteropathy, X-linked), a devastating autoimmune disorder[reference:16]. In cancer, Treg infiltration suppresses anti-tumor immunity, making FOXP3 a critical biomarker for immunotherapy response.
Yet FOXP3 detection in tissue sections faces a specificity challenge: FOXP3 belongs to the forkhead/winged-helix family of transcriptional regulators, and antibodies raised against conserved forkhead domains can cross-react with related family members, generating false-positive nuclear signal in non-Treg cells.
Strategic Epitope Selection: C-Terminal Region
Abbkine's FOXP3 Polyclonal Antibody (ABP0141) addresses this through strategic immunogen design: the antibody is raised against a synthesized peptide derived from the C-terminal region of human FOXP3[reference:17], a segment outside the highly conserved forkhead DNA-binding domain. This C-terminal targeting reduces the likelihood of cross-reactivity with other forkhead family proteins while preserving robust recognition of FOXP3.
Validated Performance Across Four Applications
ABP0141 is affinity-purified from rabbit antiserum by affinity-chromatography using the epitope-specific immunogen[reference:18] and validated for WB, IHC, IF, and ELISA:
| Application | Suggested Dilution | Validation Data |
|---|---|---|
| Western Blot | 1:500–1:2000 | Detects endogenous FOXP3 at ~47 kDa in PC12 cells[reference:19] |
| IHC | 1:100–1:300 | Validated in human tonsil and colon FFPE sections (1:100)[reference:20] |
| Immunofluorescence | 1:50–1:200 | Nuclear localization consistent with FOXP3 biology |
| ELISA | 1:20,000 | High-titer performance |
Broad Species Reactivity
| Parameter | ABP0141 |
|---|---|
| Reactivity | Human, Mouse, Rat, Pig |
| Host | Rabbit |
| Clonality | Polyclonal |
| Concentration | 1 mg/mL |
| Molecular Weight | 47 kDa |
| Formulation | PBS, 50% glycerol, 0.5% BSA, 0.02% sodium azide |
The inclusion of pig reactivity is notable—porcine models are increasingly used in transplantation immunology and Treg biology, and few commercial FOXP3 antibodies validate this species.
Head-to-Head: FOXP3 Antibody Comparison
| Feature | ABP0141 | Generic FOXP3 Antibodies |
|---|---|---|
| Epitope | C-terminal region (non-forkhead) | Often forkhead domain |
| Forkhead Family Cross-reactivity | Reduced by design | Potential concern |
| Species Reactivity | Human, Mouse, Rat, Pig | Often limited to 2–3 species |
| Applications | WB, IHC, IF, ELISA | Variable |
| IHC Validation | Tonsil + Colon (documented) | Variable |
The Bottom Line
For researchers quantifying Treg infiltration in tumor immunology, characterizing FOXP3+ cells in autoimmune models, or working with porcine transplantation systems, ABP0141 provides C-terminal epitope specificity and multi-species validation that generic forkhead-domain antibodies cannot match.
📎 Reference: FOXP3 Polyclonal Antibody (ABP0141)
