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COL1A2 / Collagen alpha-2(I) chain · IHC design guide
Design Immunohistochemistry for COL1A2
Plan COL1A2 paraffin IHC with a 1:100–1:300 antibody dilution (datasheet A00624-1). Interpret cytoplasmic tissue staining (HPA tissue IHC) alongside its secreted extracellular matrix location (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
COL1A2 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 tissue staining (HPA tissue IHC); secreted into extracellular matrix (UniProt) | |
| Staining pattern | Cytoplasmic in cervix glandular and placenta trophoblastic cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, heat-mediated (datasheet A00624-1) | |
| Positive control | Cervix+4 more · see all | |
| Negative control | None in HPA (detected in all 44 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Secreted protein: tissue RNA and protein locations may differ (HPA tissue IHC) | |
| Regulation | No specific staining regulator reported (UniProt) | |
| Isoform / epitope | No isoforms reported; propeptide cleavage may affect epitope presence (UniProt) |
Section 1
Recommended COL1A2 IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet: A00624-1) with four published COL1A2 tissue IHC methods (PMC13168407; PMC8043688; PMC6940971; PMC13173883).
| Sample | Paraffin-embedded Rat lung tissue; fixative not specified (datasheet A00624-1) |
| Fixation | Image fixative and duration unreported (datasheet A00624-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Citrate pH 6.0, 20min (datasheet A00624-1) |
| 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 anti-COL1A2, 1:100-1:300 (datasheet A00624-1) |
| 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 | COL1A2-positive staining in glandular cells of cervix (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 heat retrieval (datasheet: A00624-1); consider Tris-EDTA pH 9.0 if optimizing retrieval (PMC8043688).
Section 2
What Is the Expected COL1A2 Staining Pattern?
COL1A2 is a secreted protein of the extracellular matrix with no transmembrane segment (UniProt P08123 localization and topology). In paraffin-section IHC, assess both extracellular staining and the cell-associated staining reported by HPA: its tissue profile describes general cytoplasmic expression, with high staining in cervical glandular cells and placental trophoblastic cells (HPA: Approved tissue IHC; High in both cell types). Because it is secreted, the location of RNA and protein can differ (HPA reliability note).
| Extracellular staining accompanies cytoplasmic staining in cervical glandular cells or placental trophoblastic cells. | This is compatible with a secreted matrix protein (UniProt P08123 localization) and with the high cell-associated staining reported in those tissues (HPA: High). Compare compartments separately; HPA's tissue summary describes general cytoplasmic expression and does not assign an intensity to extracellular deposits (HPA: tissue IHC profile). |
| Predominant nuclear or sharply membranous staining, without a plausible extracellular or cytoplasmic pattern. | Treat this as a localization mismatch requiring a specificity check, rather than evidence for a new COL1A2 compartment (UniProt P08123: secreted, extracellular matrix; no transmembrane segment). Review negative controls and the IHC-validated antibody's documented staining (general IHC practice). |
| Strong staining is confined to an unexpected cell population while expected positive cells are unstained. | Cross-reactivity or endogenous detection activity is possible, but morphology alone cannot establish either cause (general IHC interpretation). Compare cervical glandular or placental trophoblastic cells on the same run (HPA: High) and check the detection-only control (general IHC practice). |
| Diffuse color covers tissue and blank areas, obscuring cellular and extracellular boundaries. | Interpret the pattern as background until controls clarify its source (general IHC practice). Excess primary antibody, incomplete blocking, or detection-system background can obscure the reported cytoplasmic pattern (HPA: tissue IHC profile; general IHC practice). |
| No interpretable signal appears in a cervical or placental section used as a positive control. | First check whether glandular or trophoblastic cells are present in the sampled section (HPA: High in those respective cells). Then assess the antibody, retrieval, detection reagents, and run controls (general IHC practice); a blank slide alone does not establish absent COL1A2. |
💡Expected COL1A2 appearanceCall the stain positive when cell-associated cytoplasmic signal in cervical glandular or placental trophoblastic cells is convincing (HPA: High), with extracellular signal interpreted in light of COL1A2 secretion (UniProt P08123); isolated nuclear or uniform nonspecific color is suspect (general IHC practice).
| Secreted protein and tissue context | COL1A2 belongs to the extracellular matrix and lacks a transmembrane segment (UniProt P08123). HPA nevertheless reports general cytoplasmic IHC staining and cautions that RNA and protein locations may differ for a secreted protein (HPA: tissue IHC profile and reliability note). Score compartments explicitly. |
| Tissue and cell-level reference | Cervical glandular cells and placental trophoblastic cells are high; adipocytes in adipose tissue and breast are medium (HPA: tissue IHC). These are observed staining levels, not a guarantee that every field or every other cell type will stain at the same intensity (general IHC interpretation). |
| Processing and antibody epitope | UniProt annotates a signal peptide, propeptides, and a mature collagen chain (UniProt P08123 processing). An antibody's epitope could therefore affect which molecular form it detects; the supplied evidence does not map that epitope. Do not infer an IHC compartment or retrieval condition from processing alone. |
| Antibody validation | The HPA tissue IHC reliability is Approved, and CAB032650 has IHC Approved status (HPA: tissue IHC; antibody validation). These labels support use of the reported pattern as a reference; they do not provide a dilution, retrieval setting, or proof that every staining event is specific. |
| Chromogenic detection background | Endogenous enzyme activity or nonspecific detection reagents can produce color independent of primary-antibody binding (general IHC practice). A detection-only control helps test this explanation; HPA's tissue levels do not establish that a particular specimen has such activity. |
| IF/ICC Q&A: should signal match IHC exactly? | No. HPA reports mainly endoplasmic-reticulum localization in ICC-IF (HPA: supported subcellular location), while tissue IHC reports general cytoplasmic expression (HPA: tissue IHC profile). Interpret each application against its own reference pattern; this observation supplies no IF/ICC protocol. |
| Situation | Likely cause | Next action |
|---|---|---|
| Cervical or placental positive control is blank. | The sampled field may lack the relevant glandular or trophoblastic cells (HPA: High in those cells), or an IHC step may have failed (general IHC practice). | Confirm the target cells on the section, then inspect the run control, antibody application, retrieval, and detection steps (general IHC practice). Avoid declaring a target-specific fixation effect; none is supplied. |
| All sections show diffuse brown color. | A detection-system or blocking problem can create widespread background (general IHC practice). | Compare the detection-only control, inspect washing and blocking, and adjust primary-antibody concentration using the antibody's IHC instructions (general IHC practice). Reassess whether cell boundaries become interpretable. |
| Color appears mainly in nuclei or as a crisp cell-surface rim. | That distribution conflicts with the supplied secreted, extracellular-matrix topology (UniProt P08123) and HPA's general cytoplasmic tissue profile (HPA: tissue IHC). | Check controls and antibody identity, then compare the same cell types with the reference pattern (general IHC practice; HPA: tissue IHC). Do not score compartment-mismatched color as confirmed COL1A2. |
| Unexpected cells stain more strongly than the reference population. | Cross-reactivity or endogenous chromogenic activity is possible; the supplied HPA positive list is not an exhaustive map of every tissue cell (HPA: tissue IHC; general IHC interpretation). | Check morphology and detection-only controls, and compare a documented high-staining tissue in the same run (HPA: cervical glandular and placental trophoblastic cells; general IHC practice). |
| Extracellular material stains but expected cells appear weak. | Secreted COL1A2 can occupy extracellular matrix (UniProt P08123), and HPA warns that secreted protein and RNA locations can differ (HPA: reliability note). | Record extracellular and cell-associated signals separately; compare with the high-staining reference cells before deciding whether the run is acceptable (HPA: tissue IHC; general IHC interpretation). |
| A proposed retrieval change is justified solely by a negative COL1A2 slide. | The supplied UniProt and HPA records establish localization and observed staining, but give no target-specific fixation sensitivity or retrieval response (UniProt P08123; HPA: tissue IHC). | Treat retrieval adjustment as a general IHC optimization, document conditions and controls, and judge the result against the reported tissue pattern (general IHC practice; HPA: tissue IHC). |
Experiment evidence
IHC & IF images showing COL1A2 staining
A00624-1 · IHCImmunohistochemical analysis of paraffin-embedded Rat-lung tissue. 1, COL1A2 Polyclonal Antibody was diluted at 1:200 (4°C, overnight). 2, S
A00624-1 · IHCImmunohistochemical analysis of paraffin-embedded Mouse-liver tissue. 1, COL1A2 Polyclonal Antibody was diluted at 1:200 (4°C, overnight). 2
A00624-1 · IFImmunofluorescence analysis of rat-lung tissue. 1, COL1A2 Polyclonal Antibody (red) was diluted at 1:200 (4°C, overnight). 2, Cy3 labled Sec
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000164692-COL1A2/tissue/cerebral+cortex#imid_12950223
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000164692-COL1A2/tissue/colon#imid_12953841
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000164692-COL1A2/tissue/liver#imid_12953834
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000164692-COL1A2/tissue/kidney#imid_12953843
HPA · ICC-IF ASC52teloHuman Protein Atlas immunofluorescence, ASC52telo, antibody HPA068464; green = COL1A2, blue = nucleus, red = microtubules.
HPA · ICC-IF ASC52teloHuman Protein Atlas immunofluorescence, ASC52telo, antibody HPA068464; green = COL1A2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for COL1A2 IHC & IF
🧪Run cervix first: glandular cells should stain (HPA: High in cervix glandular cells), while nuclei should remain unstained (UniProt P08123: secreted, extracellular matrix). HPA detects COL1A2 in all 44 scored tissues (HPA: no negative rows), so no negative tissue is supported; no-primary and isotype slides carry the negative controls.
Positive control tissue: Cervix (Glandular cells, HPA High)
Negative control tissue: None in HPA: COL1A2 is detected in all 44 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show COL1A2 in ASC52telo, BJ [Human fibroblast], U2OS, with annotated localisation: Endoplasmic reticulum (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only slide, nonimmune IgG from the polyclonal primary’s host species as an isotype control, and an identically processed COL1A2-knockout specimen if available (catalog caption: polyclonal antibody and secondary-only negative control; standard IHC control practice). For chromogenic detection, block endogenous peroxidase and assess background in the cervix section (standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported, and the selected paraffin-section caption does not state a fixative (catalog caption: A00624-1). That caption uses sodium citrate at pH 6.0, > 98°C for 20 min; it does not establish retrieval dependence, and the supplied evidence does not show whether frozen sections or IF would be easier (catalog caption: A00624-1). In cervix, extracellular matrix staining around glands can complicate attribution of signal to glandular cells (UniProt P08123: extracellular matrix; HPA: High in cervix glandular cells).
HPA tissue IHC evidence for COL1A2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Secreted protein, tissue location of RNA and protein is expected to differ.). 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 |
|---|---|---|---|---|
| Cervix | Glandular cells | High | Protein (IHC) | HPA → |
| Placenta | Trophoblastic cells | High | Protein (IHC) | HPA → |
| Adipose tissue | Adipocytes | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: COL1A2 is detected in all 44 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced COL1A2 IHC Tips
Troubleshoot COL1A2 staining by evaluating retrieval, tissue processing, intracellular signal and extracellular matrix deposition together (UniProt P08123; HPA tissue IHC).
How should I retrieve COL1A2 in paraffin sections when staining is weak?
Start with heat-mediated citrate retrieval at pH 6.0, matching this page’s IHC protocol (datasheet A00624-1). The selected paraffin-embedded rat-lung image used sodium citrate above 98°C for 20 minutes, followed by primary antibody at 1:200 overnight at 4°C (caption A00624-1). Keep section thickness, cooling and staining conditions consistent while assessing retrieval, since those variables can change chromogenic signal (standard IHC practice). If staining remains weak, compare a small retrieval-time series while monitoring tissue integrity and background (standard IHC practice). Interpret recovered signal in light of both extracellular matrix localisation and the reported cytoplasmic tissue staining (UniProt P08123 localisation; HPA tissue IHC).
Does fixation explain weak or uneven COL1A2 staining in my paraffin sections?
The selected image documents paraffin-embedded rat lung but does not state a fixative, so COL1A2-specific fixation sensitivity is unknown (caption A00624-1). Record the fixative, fixation duration and processing history for each specimen before attributing weak staining to the antibody (standard IHC practice). Compare sections processed together and apply the same citrate pH 6.0 retrieval when testing whether a processing difference tracks the signal (datasheet A00624-1; standard IHC practice). Inspect morphology alongside staining, because damaged or poorly preserved sections complicate chromogenic interpretation (standard IHC practice). Neither extracellular localisation nor reported tissue staining establishes how this antibody responds to a particular fixative (UniProt P08123 localisation; HPA tissue IHC).
Should COL1A2 appear in cells, extracellular matrix, or both?
COL1A2 is a secreted extracellular matrix protein with no transmembrane segment, so assess deposited material outside cells as well as cellular staining (UniProt P08123 localisation and topology). The tissue atlas describes general cytoplasmic expression, while its subcellular IF summary supports endoplasmic reticulum localisation (HPA tissue IHC; HPA subcellular). These observations can coexist with secretion, but a cellular signal alone does not show how much collagen was deposited (UniProt P08123 function and localisation; HPA subcellular). Examine chromogen against cell boundaries and surrounding matrix using the counterstain to separate these compartments (standard IHC practice). Document their distribution separately rather than treating every brown region as the same biological readout (standard IHC practice).
Could processing or epitope location change what this COL1A2 antibody detects?
COL1A2 has 0 listed isoforms, but the precursor is processed into a collagen chain spanning residues 80–1119 (UniProt P08123 processing and isoforms). Its signal peptide spans residues 1–22, and propeptide regions include 23–79 and 1120–1366 (UniProt P08123 processing). Glycosylation and hydroxylation are also recorded, so epitope accessibility may depend on which molecular region the antibody recognises (UniProt P08123 glycosylation and modified residues; standard IHC practice). Check the catalog antibody’s documented immunogen or epitope before assigning cellular and matrix signals to the same processed form (standard IHC practice). If that information is unavailable, report compartment-specific staining without claiming discrimination between precursor, propeptide and mature chain (UniProt P08123 processing; standard IHC practice).
How can IF help resolve ambiguous chromogenic COL1A2 staining?
On the separate IF/ICC workflow, multiplex COL1A2 with a marker for the cell population being examined; reported high tissue-IHC signals include cervix glandular and placenta trophoblastic cells (HPA tissue IHC). Choose a fluorophore channel with low tissue autofluorescence and inspect single-channel controls before interpreting overlap (standard IF practice). For an intracellular endoplasmic reticulum epitope, include a controlled permeabilisation step; for accessible deposited extracellular collagen, test conditions that preserve matrix structure (HPA subcellular; UniProt P08123 localisation; standard IF practice). COL1A2 has no transmembrane segment, so antibody access depends on the epitope’s intracellular or extracellular location rather than membrane orientation (UniProt P08123 topology and localisation). Use spatial overlap to refine localisation, while confirming any cell-type assignment with the companion marker (standard IF practice).
What controls distinguish COL1A2 signal from chromogenic background?
The selected rat-lung image includes a secondary-antibody-only negative control, which helps reveal secondary-reagent or detection background (caption A00624-1). Run a matched control with each staining batch and compare its chromogen distribution with the primary-antibody section (standard IHC practice). Include a peroxidase-blocking step when using enzyme-based chromogenic detection, and inspect endogenous pigment and tissue edges before calling faint DAB positive (standard IHC practice). Titrate detection intensity if diffuse brown staining obscures boundaries between cells and extracellular matrix (standard IHC practice; UniProt P08123 localisation). Treat signal confined to the secondary-only control, damaged edges or necrotic regions as suspect until it is resolved by controls and morphology (caption A00624-1; standard IHC practice).
How should I quantify COL1A2 when cell staining and matrix staining coexist? ⚠ ANSWER MARKED FOR VERIFICATION
Define cellular and extracellular regions separately before scoring because COL1A2 is secreted, while the tissue atlas also reports cytoplasmic staining (UniProt P08123 localisation; HPA tissue IHC). For cells, report the percentage positive and a prespecified intensity score, or an H-score if that scoring scheme fits the question (standard IHC practice). For deposited matrix, measure positive area or optical density per mm² within a consistently defined region (standard IHC practice). Normalise cell results to evaluable cells and matrix results to evaluable tissue area, excluding folds and missing tissue by the same rule across samples (standard IHC practice). Hold threshold, counterstain and image-acquisition settings constant within a comparison (standard IHC practice).
What pattern supports a true COL1A2 result rather than an artefact?
A plausible result can include extracellular matrix staining and cellular signal consistent with secretion or endoplasmic reticulum localisation (UniProt P08123 localisation; HPA subcellular). Compare cellular staining with the tissue context: high glandular-cell staining in cervix and high trophoblastic-cell staining in placenta are reported observations, not universal requirements (HPA tissue IHC). A pattern confined to nuclei, section edges or necrotic material needs scrutiny because it does not by itself establish the documented localisation (UniProt P08123 localisation; standard IHC practice). Check the secondary-only control and assess endogenous enzyme activity or pigment when brown signal appears in unexpected compartments (caption A00624-1; standard IHC practice). Interpret a weak or absent region alongside preservation, retrieval consistency and nearby positive staining before drawing a biological conclusion (standard IHC practice).
Boster reagents
Best COL1A2 / Collagen alpha-2(I) chain IHC Antibodies
The anti-COL1A2 antibody A00624-1 has IHC images from paraffin-embedded rat lung and mouse liver, and IF images from rat lung and NIH/3T3 cells (catalog image captions).
Real IHC data
Anti-Collagen alpha-2(I) chain COL1A2 Antibody
Cat # A00624-1
A00624-1 has IHC image evidence from paraffin-embedded rat lung and mouse liver (catalog IHC image captions). Its IF captions show rat lung tissue and NIH/3T3 cells; the catalog lists Human, Mouse and Rat reactivity (catalog IF image captions; catalog reactivity).
Which to pick: For tissue IHC, choose A00624-1: its own captions document paraffin-embedded rat lung and mouse liver stained at 1:200 after sodium citrate pH 6.0 retrieval (A00624-1 IHC image captions). For IF in tissue or cells, choose the same rabbit polyclonal antibody, whose IF captions show rat lung and NIH/3T3 cells (catalog host; A00624-1 IHC and IF image captions). Its listed Human, Mouse and Rat reactivity supports cross-species selection, though the IHC images show rat and mouse tissue only; the IHC captions do not report the fixative (catalog reactivity; A00624-1 IHC image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P08123 (CO1A2_HUMAN, Collagen alpha-2(I) chain).
- Human Protein Atlas. COL1A2 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. COL1A2 subcellular location (ICC-IF): Mainly localized to the endoplasmic reticulum..
- Human Protein Atlas. COL1A2 antibody validation summary (3 antibodies).
- Collagen type I alpha 2 acts as a potential diagnostic biomarker and therapeutic targets for the prognosis in gastric cancer. Discover oncology 2026 — PMC13168407.
- Expression of cornulin in tongue squamous cell carcinoma. Ecancermedicalscience 2021 — PMC8043688.
- A Novel Hepatic Anti-Fibrotic Strategy Utilizing the Secretome Released from Etanercept-Synthesizing Adipose-Derived Stem Cells. International journal of molecular sciences 2019 — PMC6940971.
- Microbiota-gut-muscle axis shapes fish muscle texture by regulating collagen synthesis. Microbiome 2026 — PMC13173883.
- PubMed PMID:2824475 — UniProt-cited evidence.
- PubMed PMID:9016532 — UniProt-cited evidence.
- PubMed PMID:9443882 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for COL1A2 (Collagen alpha-2(I) chain). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC); secreted into extracellular matrix (UniProt). Antigen retrieval: Citrate pH 6.0 HIER, heat-mediated (datasheet A00624-1). Validated IHC antibody: A00624-1 at 1:100-1:300 (the product's own IHC validation image is shown). Controls (HPA): positive Cervix (Glandular cells); negative None in HPA (detected in all 44 tissues); use no-primary + isotype controls. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded Rat lung tissue; fixative not specified (datasheet A00624-1); 2. Fixation: Image fixative and duration unreported (datasheet A00624-1); 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 retrieval: Citrate pH 6.0 , 20min (datasheet A00624-1); 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 anti-COL1A2, 1:100-1:300 (datasheet A00624-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Secreted protein: tissue RNA and protein locations may differ (HPA tissue IHC); Isoform / epitope: No isoforms reported; propeptide cleavage may affect epitope presence (UniProt); Regulation: No specific staining regulator reported (UniProt). Evidence: UniProt P08123, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the endoplasmic reticulum., Datasheet A00624-1, PMC13168407, PMC8043688. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/COL1A2/immunohistochemistry-ihc-guide.