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HAPLN1 / Hyaluronan and proteoglycan link protein 1 · IHC design guide
Design Immunohistochemistry for HAPLN1
Plan chromogenic HAPLN1 IHC in paraffin sections using the human placenta example at 2 μg/ml (datasheet A05980-3). Interpret selective cytoplasmic tissue staining (HPA tissue IHC) alongside its secreted extracellular location (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
HAPLN1 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 | Observed cytoplasmic staining (HPA tissue IHC); expected extracellular matrix location (UniProt) | |
| Staining pattern | Selective cytoplasmic staining in cartilage, placenta and CNS, including decidual cells (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A05980-3) | |
| Positive control | Placenta+1 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A05980-3) | |
| Caveat | Secreted protein may stain away from cells expressing its RNA (HPA tissue IHC) | |
| Regulation | Regulation not reported (UniProt) | |
| Isoform / epitope | No isoforms; propeptide cleaved; no cytoplasmic region (UniProt) |
Section 1
Recommended HAPLN1 IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet: A05980-3) with two published chromogenic HAPLN1 protocols (PMC6328344; PMC3761224).
| Sample | Paraffin-embedded human placenta tissue; fixative not specified (datasheet A05980-3) |
| Fixation | Image fixative and duration unreported (datasheet A05980-3); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A05980-3); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A05980-3) |
| Primary antibody | Rabbit anti-HAPLN1, 2-5 μg/ml (datasheet A05980-3) |
| Primary incubation | Overnight at 4 °C (datasheet A05980-3) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A05980-3) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | HAPLN1-positive staining in decidual cells of placenta (HPA tissue IHC: Medium). HPA tissue profile: Selective cytoplasmic expression in cartilage, placenta and CNS. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet: A05980-3). The published protocols used citrate retrieval with their own antibodies (PMC6328344; PMC3761224).
Section 2
What Is the Expected HAPLN1 Staining Pattern?
HAPLN1 is secreted into the extracellular matrix and has no transmembrane segment (UniProt P10915). In paraffin IHC, assess cartilage-associated staining and selective cytoplasmic staining in placenta and CNS (HPA tissue IHC: Enhanced; medium consistency with RNA). Decidual cells and elongated or late spermatids show medium staining, while the listed CNS cell populations show low staining (HPA tissue IHC). Protein location need not match the tissue where its RNA is detected (HPA tissue IHC).
| Cartilage-associated staining with selective cytoplasmic staining in placenta or CNS (HPA tissue IHC). | This fits the reported tissue profile (HPA tissue IHC). Extracellular staining is biologically plausible because HAPLN1 stabilizes proteoglycan aggregates in cartilage matrix (UniProt P10915). Score cellular and matrix signal separately; the record does not give a cartilage intensity threshold (HPA tissue IHC). |
| Medium staining in decidual cells or elongated or late spermatids; low staining in the listed CNS cells (HPA tissue IHC). | These are the reported cell-specific levels, including low neuronal staining in cerebral cortex, hippocampus and caudate (HPA tissue IHC). A weak CNS signal can therefore be consistent with HAPLN1; compare it with background and a stronger positive control before calling it absent (HPA tissue IHC; general IHC practice). |
| Predominantly nuclear staining without the reported cellular or cartilage-associated pattern (HPA tissue IHC; UniProt P10915). | A nuclear-only result conflicts with the reported cytoplasmic tissue profile and secreted extracellular localization (HPA tissue IHC; UniProt P10915). Review morphology and control slides, then assess whether nonspecific detection or misidentified structures explain the signal (general IHC practice). |
| Strong staining in adipocytes or other cells reported as not detected (HPA tissue IHC). | Adipocytes in adipose tissue and glandular cells in adrenal gland are reported as not detected (HPA tissue IHC). If staining is reproducible, assess antibody specificity and endogenous chromogenic activity with appropriate controls; a single unexpected stain does not establish HAPLN1 expression (general IHC practice). |
| Diffuse color over tissue, extracellular spaces and the negative control (general IHC practice). | This distribution cannot be assigned confidently to HAPLN1, even though HAPLN1 is extracellular (UniProt P10915). Compare a no-primary control and tissue morphology; excessive detection signal, incomplete blocking or inadequate washing are general IHC possibilities, not HAPLN1-specific findings (general IHC practice). |
💡Expected HAPLN1 appearanceCall a result positive when cartilage-associated or selective cytoplasmic staining matches the tissue profile, with medium decidual-cell staining or low CNS staining where applicable; nuclear-only or widespread control-matched color is suspect (HPA tissue IHC; UniProt P10915; general IHC practice).
| Secreted matrix protein (UniProt P10915) | HAPLN1 can be seen outside producing cells in cartilage matrix (UniProt P10915). Interpret extracellular color alongside the reported cytoplasmic tissue pattern; do not require a membrane outline, because no transmembrane segment is annotated (HPA tissue IHC; UniProt P10915). |
| Tissue and cell context (HPA tissue IHC) | Placental decidual cells and elongated or late spermatids are medium positive, whereas listed CNS populations are low and several surveyed cell types are not detected (HPA tissue IHC). Choose comparisons by annotated cell population, since an entire tissue is not uniformly positive or negative (HPA tissue IHC). |
| Protein processing and modification (UniProt P10915) | The annotated mature chain spans residues 16–354 after a 1–15 propeptide, and glycosylation sites occur at residues 21 and 56 (UniProt P10915). These annotations do not locate any antibody epitope or establish a retrieval or fixation effect; avoid predicting stain strength from them. |
| Antibody evidence (HPA antibodies; HPA tissue IHC) | HPA019105 and HPA019482 have Enhanced IHC status; HPA025238 is Approved (HPA antibodies). The tissue profile is labeled Enhanced but has medium RNA–protein consistency, with a stated caveat for secreted proteins (HPA tissue IHC). Interpret discordant sites with controls and tissue context. |
| Situation | Likely cause | Next action |
|---|---|---|
| No stain in decidual cells expected to be medium positive (HPA tissue IHC). | The run may lack sensitivity, or the selected section may lack identifiable decidual cells (general IHC practice). | Confirm cell identity and section quality, then check the IHC-validated antibody's stated retrieval and dilution conditions and the detection controls (general IHC practice). |
| Low CNS staining is scored as negative (HPA tissue IHC). | The expected signal is low in the listed CNS populations (HPA tissue IHC). | Compare cells with local background and a positive control; assess the reported cell population before making a tissue-wide call (HPA tissue IHC; general IHC practice). |
| Unexpected color appears in adipocytes reported as not detected (HPA tissue IHC). | Cross-reactivity or endogenous detection activity is possible, but the stain alone cannot distinguish them (general IHC practice). | Review a no-primary control and cellular morphology; if color persists, check blocking and the detection system before attributing it to HAPLN1 (general IHC practice). |
| Cartilage shows broad extracellular color (UniProt P10915). | Matrix localization is plausible for HAPLN1, but diffuse background can look similar (UniProt P10915; general IHC practice). | Check whether color follows cartilage structures and exceeds the no-primary control; score matrix and cellular compartments separately (HPA tissue IHC; general IHC practice). |
| Staining is mainly nuclear despite the reported cytoplasmic profile (HPA tissue IHC). | The compartment disagrees with secreted extracellular localization and the reported tissue pattern (UniProt P10915; HPA tissue IHC). | Inspect tissue morphology and controls, then verify antibody and detection specificity before interpreting nuclear color as HAPLN1 (general IHC practice). |
| IF/ICC: where should HAPLN1 appear? | HPA reports vesicles as the approved ICC–IF location; UniProt also describes secretion into extracellular space (HPA subcellular; UniProt P10915). | Interpret vesicular signal against the ICC–IF control and cell context; do not apply the paraffin IHC tissue pattern as an ICC–IF intensity threshold (HPA subcellular; HPA tissue IHC). |
Experiment evidence
IHC & IF images showing HAPLN1 staining
A05980-3 · IHCIHC analysis of HAPLN1 using anti-HAPLN1 antibody (A05980-3). HAPLN1 was detected in a paraffin-embedded section of human placenta tissue. H
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000145681-HAPLN1/tissue/cerebral+cortex#imid_5270056
HPA · BronchusHuman Protein Atlas IHC, Bronchus. Source: https://www.proteinatlas.org/ENSG00000145681-HAPLN1/tissue/bronchus#imid_5270013
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000145681-HAPLN1/tissue/colon#imid_5247854
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000145681-HAPLN1/tissue/liver#imid_5247855
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA019105; green = HAPLN1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA019105; green = HAPLN1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for HAPLN1 IHC & IF
🧪Run placenta first and expect staining in decidual cells (HPA: Medium in placental decidual cells). Use adipose tissue as the negative comparator, with adipocytes at background (HPA: Not detected in adipocytes); on the placenta slide, assess cells outside the annotated decidual compartment for background staining while scoring extracellular signal separately (UniProt P10915: secreted, extracellular matrix).
Positive control tissue: Placenta (Decidual cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show HAPLN1 in A-431, BJ [Human fibroblast], U2OS, with annotated localisation: Vesicles (approved) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) slide, a concentration-matched rabbit isotype control appropriate to the catalog antibody, and a HAPLN1 knockout specimen or immunogen-peptide competition control where available (selected-SKU caption: rabbit anti-HAPLN1 antibody; standard IHC controls). For placental DAB staining, block endogenous peroxidase and check blood-rich areas for background signal (selected-SKU caption: placenta, HRP/DAB detection; standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported in the supplied evidence, and the selected-SKU paraffin-section caption does not state a fixative (selected-SKU caption: fixative not stated). The caption uses heat-mediated EDTA retrieval at pH 8.0, but does not establish that retrieval is required; whether frozen sections or IF are easier is unreported (selected-SKU caption: EDTA retrieval). Placental blood can contribute peroxidase-related DAB background, so interpret signal against the control slides (selected-SKU caption: placenta, HRP/DAB detection; standard IHC practice).
HPA tissue IHC evidence for HAPLN1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. Secreted protein, tissue location of RNA and protein is expected to differ. Antibody staining in cells/structures not annotated, view images.). 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 |
|---|---|---|---|---|
| Placenta | Decidual cells | Medium | Protein (IHC) | HPA → |
| Testis | Elongated or late spermatids | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced HAPLN1 IHC Tips
Troubleshoot HAPLN1 chromogenic IHC by anchoring retrieval to the catalog antibody’s placenta image and interpreting staining alongside its secreted extracellular role (datasheet A05980-3; UniProt P10915).
What retrieval should I try first when HAPLN1 staining is weak in paraffin sections?
Start with heat-mediated antigen retrieval in EDTA at pH 8.0 (datasheet A05980-3). This is the retrieval used for the catalog antibody’s human placenta paraffin-section image, followed by 2 μg/ml primary antibody overnight at 4°C (datasheet A05980-3). Run a known placenta section beside the test section and compare signal with morphology after retrieval (datasheet A05980-3; standard IHC practice). If staining remains weak, adjust heating time on adjacent sections before considering another retrieval buffer, while keeping antibody concentration and detection constant (standard IHC practice). The caption identifies a paraffin section but does not report its fixative, so it cannot establish retrieval performance across fixation conditions (datasheet A05980-3).
Could fixation explain inconsistent HAPLN1 IHC across specimens?
Target-specific fixation sensitivity is unknown because the selected paraffin-section caption does not state a fixative (datasheet A05980-3). Record each specimen’s fixative and fixation interval, then compare sections processed with the same retrieval and detection conditions (standard IHC practice). Include the catalog antibody’s placenta setting as a reference: EDTA at pH 8.0, 2 μg/ml primary antibody, and overnight incubation at 4°C (datasheet A05980-3). Check whether weak signal coincides with poor tissue preservation or uneven staining before changing antibody concentration (standard IHC practice). HPA’s tissue staining and HAPLN1’s annotated glycosylation sites do not establish a fixation-dependent loss of its epitope (HPA tissue IHC; UniProt P10915).
Should I score HAPLN1 in cells, extracellular matrix, or both?
Map cellular and extracellular staining separately because HAPLN1 is annotated as secreted into the extracellular space and matrix, with no transmembrane segment (UniProt P10915). HPA reports selective cytoplasmic staining in cartilage, placenta, and CNS, and notes that a secreted protein’s RNA and protein locations can differ (HPA tissue IHC). In placenta, use the reported medium staining of decidual cells as a comparison, while documenting nearby matrix signal independently (HPA tissue IHC; standard IHC practice). The catalog image demonstrates detection in a human placenta paraffin section but does not specify which structures are positive (datasheet A05980-3). Review a no-primary control before assigning diffuse extracellular chromogen to HAPLN1 (standard IHC practice).
How should epitope uncertainty affect my interpretation of HAPLN1 staining?
The supplied record lists 0 isoforms, so these data do not support an isoform-specific staining claim (UniProt P10915). HAPLN1 has an Ig-like domain at residues 38–152 and two Link domains at 159–254 and 259–351, but the antibody epitope is not supplied (UniProt P10915; datasheet A05980-3). It also has annotated glycosylation sites at residues 21 and 56; these annotations alone cannot identify an inaccessible IHC epitope (UniProt P10915). If staining differs between preparations, compare adjacent sections under the same retrieval and detection conditions before attributing the difference to domain exposure (standard IHC practice). Report the antibody identity and retrieval condition with each comparison so the observation remains reproducible (datasheet A05980-3; standard IHC practice).
How can I follow up a placenta IHC pattern with multiplex immunofluorescence?
Pair HAPLN1 with a validated decidual-cell marker in placenta and examine each channel separately before interpreting overlap (HPA tissue IHC; standard IF practice). Choose fluorophores after checking unstained tissue autofluorescence, favoring a spectrally separated, longer-wavelength channel for a weak HAPLN1 signal (standard IF practice). Because HAPLN1 is secreted and lacks a transmembrane segment, compare nonpermeabilized staining for accessible extracellular antigen with permeabilized staining when investigating the vesicular localization reported by HPA (UniProt P10915; HPA subcellular; standard IF practice). Use single-label and no-primary controls to assess bleed-through and background (standard IF practice). The catalog caption documents chromogenic paraffin-section IHC, so its EDTA pH 8.0 retrieval and 2 μg/ml concentration should not be treated as established IF conditions (datasheet A05980-3).
How do I reduce diffuse DAB staining without losing plausible matrix signal?
First compare the stained section with a no-primary control to identify background from the detection system (standard IHC practice). Block endogenous peroxidase before HRP and DAB detection, and inspect folds and section edges for concentrated chromogen (standard IHC practice). The catalog placenta image used 10% goat serum blocking, 2 μg/ml primary antibody overnight at 4°C, and a peroxidase-conjugated secondary (datasheet A05980-3). If background persists, titrate the primary on adjacent sections while retaining the EDTA pH 8.0 retrieval reference (datasheet A05980-3; standard IHC practice). Preserve potentially meaningful extracellular signal during review because HAPLN1 is an extracellular matrix protein (UniProt P10915).
What should I measure when HAPLN1 stains both cells and matrix? ⚠ ANSWER MARKED FOR VERIFICATION
Define cellular and extracellular compartments before scoring, since HAPLN1 is secreted into the extracellular matrix while HPA also describes cytoplasmic tissue staining (UniProt P10915; HPA tissue IHC). For cellular staining, report the percentage of positive cells and an intensity-weighted H-score within a specified cell population (standard IHC practice). For matrix staining, measure positive area or staining density per mm² of evaluable tissue, using the same threshold across sections (standard IHC practice). Normalize cell counts to the total cells assessed and matrix measurements to intact tissue area, excluding folds and necrotic regions consistently (standard IHC practice). Record retrieval and chromogen settings alongside scores because changes in either can alter apparent signal (standard IHC practice).
What would make a positive HAPLN1 stain convincing rather than artefactual?
A convincing result has reproducible signal in an anatomically defined compartment and a clean no-primary control (standard IHC practice). Placenta is a documented setting for the catalog antibody, and HPA reports medium staining in decidual cells there (datasheet A05980-3; HPA tissue IHC). Consider both cell-associated staining and nearby matrix distribution because HPA describes cytoplasmic staining while UniProt places secreted HAPLN1 in extracellular matrix (HPA tissue IHC; UniProt P10915). Be cautious with a pattern confined to section edges, necrotic areas, or sites of residual endogenous peroxidase activity (standard IHC practice). Strong membrane-only staining warrants review because the supplied topology has no transmembrane segment (UniProt P10915).
Boster reagents
Best HAPLN1 / Hyaluronan and proteoglycan link protein 1 IHC Antibodies
IHC images show human placenta (A05980-3 caption), plus rat liver, mouse skeletal muscle and heart, and human glioblastoma (M05980-1 captions); IF images have unspecified samples (M05980-1 IF captions).
Real IHC data
Anti-HAPLN1 Antibody ®
Cat # A05980-3
A05980-3 has IHC data from a paraffin-embedded human placenta section (A05980-3 IHC caption). M05980-1 has IHC images from paraffin-embedded rat liver, mouse skeletal muscle and heart, and human glioblastoma, plus IF images with unspecified samples (M05980-1 image captions).
Which to pick: For human placenta tissue IHC, choose A05980-3: its polyclonal antibody was shown on a paraffin-embedded section with EDTA retrieval at pH 8.0 and 2 μg/ml primary antibody (A05980-3 catalog and IHC caption). For IF/ICC, choose monoclonal M05980-1 because those applications and IF images are listed, although the IF sample is unspecified (M05980-1 catalog and IF captions). For IHC across human, mouse and rat samples, M05980-1 has paraffin-section images from all three species; the fixative is unreported in both SKUs’ IHC captions (M05980-1 and A05980-3 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P10915 (HPLN1_HUMAN, Hyaluronan and proteoglycan link protein 1).
- Human Protein Atlas. HAPLN1 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. HAPLN1 subcellular location (ICC-IF): Localized to vesicles..
- Human Protein Atlas. HAPLN1 antibody validation summary (3 antibodies).
- Age-Related Changes in HAPLN1 Increase Lymphatic Permeability and Affect Routes of Melanoma Metastasis. Cancer discovery 2019 — PMC6328344.
- Astrocytic Regulation of Aberrant Perineuronal Net Formation in Mecp2-Null Neocortex. Journal of neurochemistry 2026 — PMC13316734.
- The matrisome: in silico definition and in vivo characterization by proteomics of normal and tumor extracellular matrices. Molecular & cellular proteomics : MCP 2012 — PMC3322572.
- Protumorigenic role of HAPLN1 and its IgV domain in malignant pleural mesothelioma. Clinical cancer research : an official journal of the American Association for Cancer Research 2009 — PMC3761224.
- PubMed PMID:2320422 — UniProt-cited evidence.
- PubMed PMID:2336413 — UniProt-cited evidence.
- PubMed PMID:2286376 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for HAPLN1 (Hyaluronan and proteoglycan link protein 1). Expected localisation Observed cytoplasmic staining (HPA tissue IHC); expected extracellular matrix location (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A05980-3). Validated IHC antibody: A05980-3 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Placenta (Decidual cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human placenta tissue; fixative not specified (datasheet A05980-3); 2. Fixation: Image fixative and duration unreported (datasheet A05980-3); 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: EDTA pH 8.0 (datasheet A05980-3); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A05980-3); 8. Primary antibody: Rabbit anti-HAPLN1, 2-5 μg/ml (datasheet A05980-3); 9. Primary incubation: Overnight at 4 °C (datasheet A05980-3). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A05980-3); Caveat: Secreted protein may stain away from cells expressing its RNA (HPA tissue IHC); Isoform / epitope: No isoforms; propeptide cleaved; no cytoplasmic region (UniProt); Regulation: Regulation not reported (UniProt). Evidence: UniProt P10915, HPA tissue IHC · Enhanced, HPA ICC-IF · vesicles., Datasheet A05980-3, PMC6328344, PMC3761224. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/HAPLN1/immunohistochemistry-ihc-guide.