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STAT2 / Signal transducer and activator of transcription 2 · IHC design guide
Design Immunohistochemistry for STAT2
Plan STAT2 paraffin IHC using tonsil squamous cells as a high-staining control (HPA tissue IHC) and the catalog antibody at 2–5 µg/mL (datasheet: A01360). Score cytoplasmic tissue staining (HPA tissue IHC), allowing for IFN-induced nuclear translocation (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
STAT2 Immunohistochemistry Experimental Design Guide
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before staining
| Expected localisation | Cytoplasmic in tissues (HPA tissue IHC); nuclear after IFN (UniProt) | |
| Staining pattern | Cytoplasmic in most tissues; high in tonsil squamous cells (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen) | |
| Positive control | Tonsil+4 more · see all | |
| Negative control | Adipose tissue+2 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep formalin fixation consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | IFN activation can shift signal into nuclei (UniProt) | |
| Regulation | Type I IFN drives nuclear translocation (UniProt) | |
| Isoform / epitope | 2 isoforms; confirm epitope coverage for each (UniProt) |
Section 1
Recommended STAT2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is accompanied by published STAT2 chromogenic staining methods from two articles (PMC6480560; PMC4206267).
| Sample | Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet M01360) |
| Fixation | Image fixative and duration unreported (datasheet M01360); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat-induced epitope retrieval in Tris-EDTA buffer, pH 9.0, 20 min at 95–98 °C (standard rule: nuclear antigen) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% normal serum of the secondary host, 30 min, room temperature (standard) |
| Primary antibody | Rabbit monoclonal (clone HCB-19) anti-STAT2, 1:50 (datasheet M01360) |
| Primary incubation | Overnight at 4 °C (standard) |
| Detection | HRP-polymer secondary, DAB chromogen 5–10 min (standard) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | STAT2-positive staining in squamous epithelial cells of tonsil (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in most tissues. No signal in the no-primary control. |
💡Decision noteStart with Tris-EDTA pH 9.0 retrieval at 95–98 °C for 20 min (page antigen-retrieval setting); citrate pH 6 is a published alternative (PMC6480560).
Section 2
What Is the Expected STAT2 Staining Pattern?
In paraffin tissue IHC, expect predominantly cytoplasmic STAT2 staining across many tissues (HPA: cytoplasmic expression in most tissues), including strong staining in tonsil squamous epithelial cells and urinary bladder urothelial cells (HPA: High in both). HPA rates the tissue pattern Approved, with medium consistency against RNA data (HPA: tissue IHC reliability). STAT2 is a non-membrane protein that can enter the nucleus after IFN-alpha/beta activation (UniProt P52630: topology and localization).
| Clear cytoplasmic staining in tonsil squamous epithelium or bladder urothelium. | This fits the reported High staining in those cell types (HPA: tissue IHC). Judge the named cells, rather than every structure in the section; HPA reports cytoplasmic expression in most tissues, not uniform intensity in every cell (HPA: tissue IHC profile). |
| Staining outlines luminal material or extracellular spaces, with little cell-associated signal. | That distribution does not fit STAT2's cytoplasmic and potentially nuclear localization (UniProt P52630: localization). Check whether the signal follows tissue edges or deposits before calling it specific. Nuclear staining alone is not automatically wrong: STAT2 can move into nuclei after IFN-alpha/beta activation (UniProt P52630: localization). |
| Strong signal is assigned to adipocytes, cardiomyocytes, or liver cholangiocytes. | HPA lists STAT2 as not detected in those particular cell types (HPA: tissue IHC). Recheck cell identification and controls; cross-reactivity or endogenous detection activity is possible. These cell-level observations do not make the entire adipose, heart, or liver section a negative control. |
| Diffuse chromogen covers cells, stroma, and blank areas without a cellular pattern. | This is difficult to score as STAT2 because HPA describes a cytoplasmic tissue pattern (HPA: tissue IHC profile). General IHC checks include the no-primary control, reagent background, blocking, washes, and endogenous enzyme activity; none of these observations alone identifies the cause. |
| No cell-associated signal appears in tonsil squamous epithelium or bladder urothelium. | This conflicts with their reported High staining (HPA: tissue IHC), but a blank slide alone cannot establish biological absence. Check the section and detection controls, then review the IHC-validated antibody's documented staining conditions. HPA's Approved rating has medium RNA–protein consistency (HPA: tissue IHC reliability). |
💡Expected STAT2 appearanceA convincing positive is cell-associated, predominantly cytoplasmic staining in tonsil squamous epithelial cells or bladder urothelial cells at the reported High level (HPA: tissue IHC); extracellular deposits or uniform section-wide color are suspect when they lack that cellular distribution.
| Activation and compartment | STAT2 occupies cytoplasm and nucleus, and moves into the nucleus after IFN-alpha/beta activation (UniProt P52630: localization). Interpret nuclear signal against the experiment's stimulation context; HPA's tissue survey describes predominantly cytoplasmic staining (HPA: tissue IHC profile). |
| Cell type and control choice | Use the reported cell type when comparing sections: tonsil squamous epithelium and bladder urothelium are High, while adipocytes and cardiomyocytes are not detected (HPA: tissue IHC). A tissue name alone does not specify which cells should stain. |
| Antibody evidence | HPA lists HPA018888 and CAB003858 as IHC Approved (HPA: antibody validation). The supplied record does not label either IHC result Enhanced. Approved tissue staining and medium RNA–protein consistency support cautious pattern comparison, not a guarantee that every specimen will match (HPA: tissue IHC reliability). |
| Antigen and isoforms | UniProt lists 2 STAT2 isoforms, a continuous 1–851 chain, no signal peptide, and no transmembrane segment (UniProt P52630: isoforms, processing, topology). Epitope coverage across isoforms cannot be inferred without the antibody's epitope information; do not infer secretion or shedding from this record. |
| Fixation and retrieval evidence | Target-specific fixation sensitivity and a STAT2 retrieval condition are unreported in the supplied UniProt and HPA records. Antigen retrieval is a general paraffin IHC workflow variable; assess it with the antibody's documented IHC conditions and controls, without assigning a STAT2-specific effect. |
| IF/ICC Q: What localization should I expect? | A: HPA reports supported cytosol and approved mid piece localization, with approved plasma membrane and principal piece locations in ICC-IF (HPA: subcellular). This is a separate imaging context; use the IF/ICC guide for its procedure and interpret tissue IHC against HPA's cytoplasmic tissue profile (HPA: tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| Known-positive cells are blank. | A failed staining run, poorly functioning detection, or unsuitable antibody conditions are possibilities; HPA reports High staining in tonsil squamous epithelium and bladder urothelium (HPA: tissue IHC). | Confirm those cells are present, inspect the run controls, and follow the IHC-validated antibody's documented paraffin-section conditions. Evaluate any retrieval adjustment against a positive control; no STAT2-specific retrieval effect is supplied. |
| Every compartment stains similarly. | Nonspecific reagent background or endogenous detection activity may obscure the cellular pattern; HPA describes cytoplasmic expression in most tissues (HPA: tissue IHC profile). | Compare a no-primary control, inspect washes and blocking, and check the detection system's endogenous activity controls. Score STAT2 only where a reproducible cell-associated pattern remains. |
| Extracellular or luminal deposits dominate. | The distribution conflicts with STAT2's cytoplasmic and nuclear localization (UniProt P52630: localization); precipitated chromogen or section debris are general IHC possibilities. | Inspect an adjacent section and a no-primary control for deposits, then repeat detection if needed. Avoid calling extracellular color positive solely because it appears near a reported positive cell type. |
| Nuclear staining appears after stimulation. | Nuclear translocation is compatible with IFN-alpha/beta activation (UniProt P52630: localization), so compartment change alone does not establish an artefact. | Compare treated and matched untreated material with the same staining conditions, and assess nuclear signal alongside cell identification and background controls. Record the stimulation context when interpreting localization. |
| Signal appears in a reported negative cell type. | HPA lists adipocytes, cardiomyocytes, and cholangiocytes as not detected (HPA: tissue IHC); cell misidentification, cross-reactivity, or endogenous detection activity may explain a discrepancy. | Verify the stained cell type morphologically, compare controls, and inspect neighboring cells separately. Do not generalize a cell-level HPA result to the entire tissue. |
| Weak signal is hard to classify. | HPA reports Low staining in several cell types, including cerebral cortex glia and thyroid glandular cells (HPA: tissue IHC); weak color can also approach background. | Compare the same cell type with its no-primary control and a reported high-staining reference on the run. Record intensity and compartment separately, and avoid treating weak diffuse color as a clear positive. |
Experiment evidence
IHC & IF images showing STAT2 staining
M01360 · IHCImmunohistochemical analysis of paraffin-embedded human lung cancer, using STAT2 Antibody.
M01360 · IFImmunofluorescent analysis of A431 cells, using STAT2 Antibody.
A01360 · IFIF analysis of STAT2 using anti-STAT2 antibody (A01360). STAT2 was detected in an immunocytochemical section of PC-3 cells. Enzyme antigen r
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000170581-STAT2/tissue/cerebral+cortex#imid_5065428
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000170581-STAT2/tissue/colon#imid_5065354
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000170581-STAT2/tissue/liver#imid_5065371
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000170581-STAT2/tissue/kidney#imid_5065356
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA018888; green = STAT2, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA018888; green = STAT2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for STAT2 IHC & IF
🧪Run tonsil first and assess staining in its squamous epithelial cells (HPA: High in tonsil squamous epithelial cells). Use heart muscle cardiomyocytes as the negative tissue (HPA: Not detected in heart muscle cardiomyocytes); the supplied HPA rows do not identify an internal negative cell population within tonsil, so do not designate one without independent validation.
Positive control tissue: Tonsil (Squamous epithelial cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show STAT2 in A-431, U-251MG, U2OS, hTERT-RPE1 (serum starved), Sperm, with annotated localisation: Cytosol (supported), Mid piece (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; an isotype control matched to the primary antibody’s host species and immunoglobulin class, with a host-immunoglobulin control for a polyclonal primary; and a matched STAT2 knockout specimen or peptide-block control if the immunizing peptide is available (standard IHC practice). For chromogenic tonsil IHC, quench endogenous peroxidase and check immune-cell background (standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported in the supplied evidence; the selected M01360 paraffin-section caption does not state a fixative (M01360 caption: fixative unreported). Antigen-retrieval dependence is unreported, and the supplied evidence does not establish whether frozen sections or IF are easier for STAT2. Assess tonsil immune-cell peroxidase background when interpreting chromogenic staining (standard IHC practice).
HPA tissue IHC evidence for STAT2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Medium consistency between antibody staining and RNA expression data.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Tonsil | Squamous epithelial cells | High | Protein (IHC) | HPA → |
| Urinary bladder | Urothelial cells | High | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Medium | Protein (IHC) | HPA → |
Section 3
Advanced STAT2 IHC Tips
Troubleshoot STAT2 chromogenic IHC by checking retrieval, staining compartment, controls, and cell-level scoring; use the IF guidance when planning a separate fluorescence assay.
What should I change when STAT2 staining is weak after antigen retrieval?
Start STAT2 chromogenic IHC with Tris-EDTA pH 9.0 HIER at 95–98 °C for 20 min (page retrieval setting). If staining remains weak, compare a shorter and a longer retrieval run around 20 min while keeping the buffer and detection conditions constant (standard IHC practice). Include a known positive tissue section, such as tonsil squamous epithelium, in each comparison (HPA: High in tonsil squamous epithelial cells). Examine morphology alongside signal, because excessive heat can damage sections and complicate cell-level scoring (standard IHC practice). Record retrieval time, temperature, and staining intensity before changing antibody concentration (standard IHC practice).
How can I assess whether fixation caused weak STAT2 staining?
The selected antibody image shows paraffin-embedded human lung cancer, but its caption does not report the fixative (M01360 image caption). Target-specific STAT2 fixation sensitivity is therefore unknown from the supplied evidence; do not infer it from tissue staining patterns or protein features (M01360 image caption; UniProt P52630). Compare sections with documented processing histories under the same Tris-EDTA pH 9.0, 95–98 °C, 20 min retrieval conditions (page retrieval setting; standard IHC practice). Check whether weak signal tracks a processing batch rather than a cell compartment (standard IHC practice). Use a positive tissue control on the same run before attributing loss to fixation (standard IHC practice).
Should STAT2 stain the cytoplasm or nucleus in paraffin sections?
Assess cytoplasmic and nuclear staining separately: STAT2 is annotated in both compartments and translocates to the nucleus after IFN-alpha/beta activation (UniProt P52630 subcellular annotation). Cytoplasmic staining across many tissues is consistent with the tissue IHC profile (HPA: cytoplasmic expression in most tissues). A nuclear signal can fit activated signaling, but total STAT2 staining alone does not establish phosphorylation or pathway activity (UniProt P52630 function; standard IHC interpretation). Score nuclei against a nuclear counterstain and compare them with adjacent cytoplasm within the same cell population (standard IHC practice). Review retrieval and section edges if apparent nuclear signal is restricted to damaged regions (standard IHC practice).
Can this stain distinguish STAT2 isoforms or phosphorylation states?
STAT2 has 2 annotated isoforms, and the supplied IHC caption does not identify the antibody epitope (UniProt P52630 isoforms; M01360 image caption). Without epitope mapping, do not assign a staining pattern to either isoform or assume that every isoform is detected (standard antibody interpretation). STAT2 also has annotated phosphorylation sites, including JAK-associated Tyr-690, but an unspecified total-STAT2 epitope cannot identify a phosphorylated state (UniProt P52630 modified residues; standard antibody interpretation). Compare signal with an independently validated modification-specific assay if activation state is the question (standard IHC practice). Document the exact antibody and epitope information obtained before comparing studies (standard IHC practice).
How should I adapt the STAT2 question to multiplex IF?
Plan the IF assay separately from this antibody’s paraffin-section IHC image, which does not establish IF performance or report fixation (M01360 image caption). Pair STAT2 with a marker that identifies the expected cell population; tonsil squamous epithelial cells are one documented high-staining tissue IHC population (HPA: High in tonsil squamous epithelial cells). Choose a fluorophore channel with low tissue autofluorescence and check single-color controls before interpreting overlap (standard IF practice). Permeabilise sufficiently for an intracellular epitope, because STAT2 is cytoplasmic and can become nuclear, with no transmembrane segment annotated (UniProt P52630 subcellular annotation and topology; standard IF practice). Validate antibody specificity and compartment patterns in IF before comparing them with chromogenic IHC (standard IF practice).
What controls help identify nonspecific STAT2 chromogenic background?
First inspect a no-primary control for secondary-reagent signal and check the peroxidase block when using enzyme-based detection (standard chromogenic IHC practice). Use matched sections and identical development times so diffuse brown deposits can be compared with cellular staining (standard IHC practice). Tonsil squamous epithelium provides a documented high-staining reference, while adipocytes are reported as not detected in adipose tissue (HPA: tonsil squamous epithelial cells High; adipose tissue adipocytes Not detected). Treat those patterns as references, since HPA reports medium consistency between antibody staining and RNA data (HPA: Approved, medium consistency). Reduce excessive detection or primary-antibody concentration only after controls identify the source of background (standard IHC practice).
How should I quantify cytoplasmic and nuclear STAT2 staining? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, because STAT2 can be cytoplasmic or nuclear (UniProt P52630 subcellular annotation). For an H-score, assign intensity 0–3 and sum intensity times the percentage of cells in each category, yielding 0–300 per compartment (standard IHC scoring practice). Alternatively, report % positive cells or positive-cell density per mm² within a documented tissue area (standard IHC scoring practice). Normalize to the number of evaluable cells or measured viable area, and exclude necrotic or damaged regions consistently (standard IHC practice). Apply one threshold across compared sections and report nuclear and cytoplasmic values separately (standard IHC practice).
How do I distinguish credible STAT2 staining from an artefact?
A credible pattern should resolve to intact cells and a plausible cytoplasmic or nuclear compartment (UniProt P52630 subcellular annotation; standard IHC practice). Compare the sampled cell population with documented tissue patterns: tonsil squamous epithelial cells are high, whereas adipocytes are reported as not detected (HPA: tonsil squamous epithelial cells High; adipose tissue adipocytes Not detected). Check whether signal instead follows tissue edges, folds, or necrosis, which can produce misleading chromogenic deposits (standard IHC practice). A no-primary control and an adequate peroxidase block help identify detection background and endogenous enzyme activity (standard chromogenic IHC practice). Interpret nuclear enrichment as compatible with activation, while reserving phosphorylation claims for a validated modification-specific assay (UniProt P52630 function; standard IHC interpretation).
Boster reagents
Best STAT2 / Signal transducer and activator of transcription 2 IHC Antibodies
Two anti-STAT2 antibodies cover human IHC and IF/ICC applications; M01360 also lists mouse and rat reactivity (catalog applications/reactivity). The supplied figures show paraffin-section IHC and cell-based IF (image captions).
Real IHC data
Anti-STAT2 Rabbit Monoclonal Antibody
Cat # M01360
Real IF data
Anti-STAT2 Antibody ®
Cat # A01360
M01360 lists IHC and IF/ICC for human, mouse and rat, with IHC shown on paraffin-embedded human lung cancer (catalog applications/reactivity; M01360 IHC caption). A01360 lists human IHC and IF/ICC, with IF shown in PC-3 cells (catalog applications/reactivity; A01360 IF caption).
Which to pick: For tissue IHC, choose M01360: its own image documents paraffin-section staining in human lung cancer, and it is monoclonal (M01360 IHC caption; catalog clone: HCB-19). For human IF/ICC, choose A01360 if the PC-3 cell image is the relevant evidence; it lists IF and ICC, while its supplied figure does not document tissue IHC (A01360 IF caption; catalog applications). For mouse or rat work, M01360 is the listed option, although its supplied IHC image is human; the fixative is unreported (catalog reactivity; M01360 IHC caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P52630 (STAT2_HUMAN, Signal transducer and activator of transcription 2).
- Human Protein Atlas. STAT2 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. STAT2 subcellular location (ICC-IF): Mainly localized to the cytosol and mid piece. In addition localized to the plasma membrane and principal piece..
- Human Protein Atlas. STAT2 antibody validation summary (2 antibodies).
- Interferon-Stimulated Genes-Mediators of the Innate Immune Response during Canine Distemper Virus Infection. International journal of molecular sciences 2019 — PMC6480560.
- IL-36 promotes anti-viral immunity by boosting sensitivity to IFN-α/β in IRF1 dependent and independent manners. Nature communications 2019 — PMC6795910.
- Decreased signal transducers and activators of transcription (STAT) protein expression in lymphatic organs during EAE development in mice. Immunology innovation 2013 — PMC4206267.
- The role of Tec kinase signaling pathways in the development of Mallory Denk Bodies in balloon cells in alcoholic hepatitis. Experimental and molecular pathology 2017 — PMC5680109.
- PubMed PMID:1502204 — UniProt-cited evidence.
- PubMed PMID:7885841 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for STAT2 (Signal transducer and activator of transcription 2). Expected localisation Cytoplasmic in tissues (HPA tissue IHC); nuclear after IFN (UniProt). Antigen retrieval: Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen). Validated IHC antibody: M01360 at 1:50 (the product's own IHC validation image is shown). Controls (HPA): positive Tonsil (Squamous epithelial cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet M01360); 2. Fixation: Image fixative and duration unreported (datasheet M01360); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat-induced epitope retrieval in Tris-EDTA buffer, pH 9.0 , 20 min at 95–98 °C…; 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% normal serum of the secondary host, 30 min , room temperature (standard); 8. Primary antibody: Rabbit monoclonal (clone HCB-19) anti-STAT2, 1:50 (datasheet M01360); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep formalin fixation consistent across sections (standard IHC practice; not target-specific); Caveat: IFN activation can shift signal into nuclei (UniProt); Isoform / epitope: 2 isoforms; confirm epitope coverage for each (UniProt); Regulation: Type I IFN drives nuclear translocation (UniProt). Evidence: UniProt P52630, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the cytosol and mid piece. In addition localized…, Datasheet M01360, PMC6480560, PMC4206267. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/STAT2/immunohistochemistry-ihc-guide.