TIGIT / CD155 Matched Pair: Workflow and Optimization for BLI and SPRPUBLISHED
TIGIT / CD155 Matched Pair: Workflow and Optimization for BLI and SPR
TL;DR
A TIGIT–CD155 matched pair (both proteins from the same source, with pre-validated binding data) removes the single biggest variable in checkpoint screening: reagent inconsistency. Capture one partner at low density, flow the other, and always check the DNAM-1 (CD226) cross-competition before trusting a "specific" blocker.
1. Biology in one paragraph
TIGIT (T-cell immunoreceptor with Ig and ITIM domains) is an inhibitory checkpoint on T and NK cells. Its primary ligand is CD155/PVR (high affinity, low-nM range reported), with a secondary ligand CD112 (nectin-2, lower affinity). Critically, CD155 also binds the activating receptor DNAM-1 (CD226) — TIGIT and DNAM-1 compete for the same ligand. Any antibody screening campaign therefore needs a *verified* TIGIT–CD155 pair to distinguish target engagement from off-target competition.
2. Why "matched pair" matters more than two proteins
- Same source, same lot philosophy — screening hits against proteins from different vendors silently mixes expression-system and glycosylation differences into your ranking.
- Pre-validated binding data — the pair should ship with SPR/BLI sensorgrams (K<sub>D</sub>, k<sub>on</sub>, k<sub>off</sub>) so you can trust your own runs.
- Cross-reactivity controls — a complete pair includes the CD155–DNAM-1 interaction data to design competition experiments.
3. Assay design (BLI/SPR)
| Step | Recommendation | Why |
|---|---|---|
| Capture | Biotinylated TIGIT on streptavidin (or His-tag capture) | TIGIT is monomeric — low-density capture keeps kinetics clean |
| Analyte | CD155 ECD (or vice versa) | Either orientation works; keep it consistent across the campaign |
| Density | Low (Rmax ~20–50 RU) | Avoids rebinding/avidity inflation |
| Regeneration | Mild (e.g., 10 mM glycine pH 2.5–3.0, short pulse) | TIGIT/CD155 is high-affinity; harsh regeneration destroys the surface |
| Competition | Pre-incubate CD155 with anti-TIGIT or anti-CD155 antibody, then inject | Confirms blockade; compare with DNAM-1 competition |
Numbers to sanity-check: reported TIGIT–CD155 K<sub>D</sub> values are typically low-nM; if your measured K<sub>D</sub> is >10–20× off from the supplier's datasheet, check your density and buffer before suspecting the protein.
4. Common mistakes
- Dimer artifacts — CD155 can oligomerize; confirm SEC monomer/dimer state on the COA before kinetic work.
- Skipping DNAM-1 control — a "blocking" antibody that only competes with TIGIT but not DNAM-1 has different biology; run both.
- Mixed vendors mid-campaign — swapping CD155 lots mid-screening corrupts the ranking; buy the pair as one unit.
- No regeneration validation — verify activity is stable over ≥5 regeneration cycles if you plan a screen.
5. What to request from your supplier
- Matched pair with SPR/BLI K<sub>D</sub> data (both directions)
- CD155 SEC state (monomer/dimer) + endotoxin
- Biotinylated TIGIT (capture format)
- Optional: CD155–DNAM-1 competition data
6. Related resources
- [TIGIT & CD155 Matched Pair](/pairs/tigit-cd155)
- [Binding Characterization Service (SPR/BLI)](/services/spr-bli)
- [Custom Checkpoint Constructs](/services/custom-protein)
What next?
- [Buy the TIGIT/CD155 Matched Pair](/request?utm_campaign=tigit-pair-guide&utm_source=site&utm_medium=organic&utm_content=cta-buy) — pre-validated binding data included
- [Request a Sample](/request?utm_campaign=tigit-pair-guide&utm_source=site&utm_medium=organic&utm_content=cta-sample) — run your own BLI before committing
- [Discuss Your Experiment](/request?utm_campaign=tigit-pair-guide&utm_source=site&utm_medium=organic&utm_content=cta-discuss) — get help with capture orientation and competition design
Next steps