This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
SLPI / Antileukoproteinase · IHC design guide
Design Immunohistochemistry for SLPI
Use this guide to plan SLPI IHC-P and assess cytoplasmic epithelial staining in cervix and respiratory tissue (HPA tissue IHC). The catalog antibody starts at 10 μg/mL; its stated IHC validation is in mouse tissue, so verify staining in human sections (datasheet).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
SLPI 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 staining in select epithelia (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic glandular and respiratory epithelial staining (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Cervix+4 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 A01682) | |
| Caveat | Secreted SLPI may appear beyond producing cells (UniProt) | |
| Regulation | No expression regulator established in the record (UniProt) | |
| Isoform / epitope | No isoforms reported; signal peptide 1–25 is cleaved (UniProt) |
Section 1
Recommended SLPI IHC & IF Protocols
The catalog antibody protocol is paired with published SLPI chromogenic IHC workflows for eye sections (PMC2234354) and head and neck tissue (PMC4164221).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet A01682); 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 citrate buffer, pH 6.0, 20 min at 95–98 °C (standard rule: cytoplasmic / membrane 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 anti-SLPI, 10 μg/mL (datasheet A01682) |
| 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 | SLPI-positive staining in glandular cells of cervix (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in cervix, respiratory epithelium, fallopian tube and seminal vesicle. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 heat retrieval at 95–98 °C for 20 min (page retrieval); PMC4164221 reports heat retrieval without specifying conditions.
Section 2
What Is the Expected SLPI Staining Pattern?
In paraffin-section IHC, expect SLPI mainly in the cytoplasm of cervix glandular cells and nasopharyngeal goblet cells, with staining in other listed epithelia (HPA: tissue IHC). SLPI is secreted and has no transmembrane segment (UniProt P03973: topology). HPA rates tissue staining Enhanced, while reporting medium agreement between staining and RNA because a secreted protein can appear away from its site of production (HPA: tissue IHC).
| Distinct cytoplasmic staining in cervix glandular cells or nasopharyngeal goblet cells; nearby cells stain less (HPA: tissue IHC). | This matches the strongest reported tissue patterns: both cell populations are High (HPA: tissue IHC). Compare the distribution among cells as well as intensity; secretion can separate the protein's location from its RNA source (HPA: reliability description; UniProt P03973: secreted). |
| A dominant nuclear or crisp cell-membrane pattern replaces epithelial cytoplasmic staining (HPA: tissue IHC pattern). | Treat that compartment mismatch as a possible artefact and check the control slide and detection reagents (HPA: tissue IHC; standard IHC practice). SLPI has no transmembrane segment, although its secreted status alone cannot identify the source of an unexpected stain (UniProt P03973: topology). |
| Cells outside the expected epithelial populations stain strongly, including adipocytes in an adipose-tissue control (HPA: tissue IHC). | Consider antibody cross-reactivity or endogenous detection activity, then compare controls and staining conditions (standard IHC practice). HPA reports adipose-tissue adipocytes as Not detected; that finding is cell-specific, not a claim that every cell in the tissue must be unstained (HPA: tissue IHC). |
| A broad, even haze obscures cell boundaries across the section, including areas without an expected positive population (standard IHC practice). | This is difficult to score as cell-associated SLPI. Review blocking, antibody concentration, washing and the detection control for background signal (standard IHC practice). HPA describes a selective cytoplasmic epithelial pattern, so diffuse haze alone does not reproduce its reported result (HPA: tissue IHC). |
| No convincing stain appears in cervix glandular cells or nasopharyngeal goblet cells (HPA: tissue IHC). | A blank known-positive region makes a negative test section inconclusive (standard IHC practice). Confirm that the positive-control cells are present, then review retrieval and detection conditions as general workflow variables; the supplied sources do not establish SLPI-specific retrieval sensitivity (HPA: tissue IHC; standard IHC practice). |
💡Expected SLPI appearanceCall the result consistent with SLPI when selected glandular or goblet cells show distinct cytoplasmic staining, strongest in cervix glandular cells or nasopharyngeal goblet cells (High, HPA: tissue IHC); widespread nuclear, membrane-only or uniform background staining is a warning to investigate, not the reported tissue pattern (HPA: tissue IHC; standard IHC practice).
| Secretion and processing (UniProt P03973). | SLPI has a signal peptide at residues 1–25 and a mature chain at 26–132, with no transmembrane segment (UniProt P03973). Interpret tissue staining in light of secretion; protein location need not match the cells with highest RNA (HPA: reliability description). |
| Cell and tissue context (HPA: tissue IHC). | HPA reports High staining in cervix glandular cells and nasopharyngeal goblet cells, Medium in bronchial respiratory epithelium, and Medium at fallopian-tube cilia tips (HPA: tissue IHC). Score the named cells and compartment rather than assigning one expected intensity to every tissue (standard IHC practice). |
| Antibody validation (HPA: antibody records). | HPA027774 and CAB002303 each have Enhanced IHC status (HPA: antibodies). That supports comparison with their reported tissue distribution but does not guarantee that an unexpected signal with a different antibody is SLPI (HPA: antibody records; standard IHC practice). |
| RNA and protein comparison (HPA: tissue IHC; UniProt P03973). | HPA calls SLPI RNA group enriched in cervix and salivary gland, yet lists salivary glandular-cell IHC as Low (HPA: tissue IHC). UniProt reports SLPI in parotid secretions (UniProt P03973: tissue specificity). Do not use RNA enrichment alone to demand strong glandular-cell staining (HPA: reliability description). |
| Situation | Likely cause | Next action |
|---|---|---|
| The positive-control cervix section is blank in glandular cells (HPA: tissue IHC). | Possible general workflow failure in retrieval, antibody incubation or detection; the supplied sources give no SLPI-specific retrieval setting (standard IHC practice). | Verify that glandular cells are present, inspect the staining run's controls, and optimize retrieval and antibody conditions for the IHC-validated antibody before interpreting test negatives (standard IHC practice). |
| The whole section has diffuse chromogen, including tissue expected to be negative (standard IHC practice). | Possible excess antibody, inadequate washing or endogenous detection activity (standard IHC practice). | Review antibody concentration, wash steps and the detection control; suppress endogenous enzyme activity when the chosen chromogen system requires it (standard IHC practice). Then reassess the selective epithelial pattern (HPA: tissue IHC). |
| Adipocytes stain as strongly as the expected epithelial cells (HPA: tissue IHC). | Possible nonspecific antibody binding or endogenous detection activity; HPA lists adipose-tissue adipocytes as Not detected (HPA: tissue IHC; standard IHC practice). | Compare a control lacking primary antibody and an independent IHC-validated antibody, if available; interpret any persistent signal in its cell-specific context (standard IHC practice; HPA: antibody records). |
| The main signal looks nuclear or sharply membrane bound (HPA: tissue IHC pattern). | Possible artefact or off-target staining; HPA's tissue summary describes cytoplasmic expression, and UniProt lists no transmembrane segment (HPA: tissue IHC; UniProt P03973: topology). | Recheck the compartment at higher magnification and compare an IHC-validated antibody and detection control before calling those cells positive (HPA: antibody records; standard IHC practice). |
| Salivary glandular cells stain weakly despite RNA enrichment (HPA: tissue IHC). | That combination is compatible with HPA's Low glandular-cell stain and its warning that secreted protein and RNA locations may differ (HPA: tissue IHC). | Score the observed glandular-cell signal against HPA's Low category, and use a high-staining epithelial control to judge run performance (HPA: tissue IHC; standard IHC practice). |
| Q: Does a Golgi-pattern IF/ICC image contradict cytoplasmic tissue IHC? (HPA: subcellular; tissue IHC) | A: HPA approves Golgi localization in ICC-IF and describes cytoplasmic expression in tissue IHC; these are observations from different assay contexts (HPA: subcellular; tissue IHC). | Use the Golgi result to interpret an IF/ICC image on its own guide page; judge paraffin-section IHC against the reported epithelial tissue pattern (HPA: subcellular; tissue IHC). |
Experiment evidence
IHC & IF images showing SLPI staining
A01682 · IHCImmunohistochemistry of SLPI in mouse lung tissue with SLPI antibody at 10 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000124107-SLPI/tissue/cerebral+cortex#imid_6974704
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000124107-SLPI/tissue/colon#imid_6962806
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000124107-SLPI/tissue/liver#imid_6962823
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000124107-SLPI/tissue/kidney#imid_6962816
HPA · ICC-IF EFO-21Human Protein Atlas immunofluorescence, EFO-21, antibody HPA027774; green = SLPI, blue = nucleus, red = microtubules.
HPA · ICC-IF EFO-21Human Protein Atlas immunofluorescence, EFO-21, antibody HPA027774; green = SLPI, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for SLPI IHC & IF
🧪Run cervix first: glandular cells should stain strongly (HPA: High in cervix glandular cells). Use adrenal gland glandular cells as the negative tissue (HPA: Not detected in adrenal gland glandular cells); on the cervix slide, assess nonglandular cells for background-level staining without assuming they are a validated biological negative (standard IHC practice).
Positive control tissue: Cervix (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show SLPI in EFO-21, SiHa, U2OS, with annotated localisation: Golgi apparatus (approved) (HPA subcellular).
Technical controls: Include no-primary (secondary-only) and matched isotype controls, using the antibody host species and the appropriate monoclonal subclass or polyclonal nonimmune immunoglobulin; confirm specificity with SLPI knockout tissue or peptide competition if the immunizing peptide is available (standard IHC practice). For chromogenic cervix IHC, block endogenous peroxidase and assess background on the no-primary slide; block endogenous biotin if using avidin–biotin detection (standard IHC practice).
⚠️Feasibility: No target-specific fixation window, fixation effect, or retrieval dependency is reported in the supplied evidence; the 10 µg/mL mouse lung IHC caption does not report its fixative (A01682 caption). Optimize antigen retrieval on paraffin cervix sections empirically; the supplied evidence does not establish that frozen sections or IF are easier (standard IHC practice; A01682 caption). Because SLPI is secreted, assess glandular cell staining separately from luminal or extracellular signal, which could complicate scoring (UniProt P03973: Secreted; HPA: High in cervix glandular cells).
HPA tissue IHC evidence for SLPI
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.). 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 → |
| Nasopharynx | Goblet cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Medium | Protein (IHC) | HPA → |
| Fallopian tube | Ciliated cells (tip of cilia) | Medium | Protein (IHC) | HPA → |
| Kidney | Cells in tubules | 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 | Endocrine 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 SLPI IHC Tips
Troubleshoot SLPI staining in paraffin section IHC by checking retrieval, compartment, controls, and cell specific scoring before interpreting signal.
What retrieval should I try when SLPI staining is weak in paraffin sections?
Start with citrate pH 6.0 heat induced retrieval at 95–98 °C for 20 min (page retrieval rule). Keep section thickness, cooling, and antibody incubation consistent while comparing runs, so any change in staining can be attributed to retrieval (standard IHC practice). Score epithelial cytoplasm against a known positive compartment: cervix glandular cells show high staining, while bronchial respiratory epithelial cells show medium staining (HPA tissue IHC). If staining remains weak, compare a longer citrate exposure on serial sections and watch for damaged morphology or increased background (standard IHC practice).
Could fixation explain variable SLPI staining between paraffin blocks?
Target specific fixation sensitivity is unknown because no SLPI fixation comparison is supplied (evidence payload). The mouse lung IHC caption reports 10 µg/mL antibody but does not state the fixative, so it cannot establish fixation tolerance (catalog antibody caption, A01682). Compare blocks with documented fixation histories using identical citrate pH 6.0 retrieval and the same detection conditions (page retrieval rule; standard IHC practice). Include a consistently processed positive control on each run, and judge whether differences track fixation history before adjusting antibody concentration (standard IHC practice). Preserve morphology when testing changes to processing or retrieval (standard IHC practice).
Where should convincing SLPI signal appear in tissue IHC?
Expect epithelial cytoplasmic staining in cervix, respiratory epithelium, fallopian tube, or seminal vesicle, while identifying the stained cell type explicitly (HPA tissue IHC). SLPI is secreted and has no transmembrane segment, so extracellular signal can accompany staining in producing cells (UniProt P03973 topology and subcellular annotation). A Golgi pattern is supported in cell imaging, although a chromogenic tissue section may not resolve that structure clearly (HPA subcellular; standard IHC practice). Compare glandular, goblet, or respiratory epithelial cells with neighboring compartments on the same section rather than calling every luminal deposit cellular expression (HPA tissue IHC; standard IHC interpretation).
How should SLPI processing affect antibody epitope interpretation?
SLPI has a 1–25 signal peptide and a mature 26–132 chain, so the location of the recognized epitope matters when interpreting processed protein (UniProt P03973 processing). Its 2 WAP domains span residues 28–76 and 82–130, and the supplied record lists 0 isoforms and 0 glycosylation sites (UniProt P03973 domains, isoforms, glycosylation). The antibody epitope is unspecified in the payload, so do not assign staining to either WAP domain or the signal peptide (evidence payload). If staining changes with retrieval, compare serial sections under controlled conditions before attributing the change to SLPI processing (standard IHC practice).
How can I check an IHC localisation finding with multiplex IF?
Use the separate IF/ICC workflow to pair SLPI with an epithelial marker that identifies the expected glandular, goblet, or respiratory cells (HPA tissue IHC; standard IF practice). Choose spectrally separated fluorophores and inspect an unstained section first, because tissue autofluorescence can mimic weak signal (standard IF practice). If the antibody epitope is intracellular, use a mild permeabilisation trial, such as 0.1% detergent, and compare it with an unpermeabilised section; SLPI is secreted and lacks a transmembrane segment (standard IF practice; UniProt P03973 topology). Confirm apparent overlap in individual channels and with secondary only controls before treating it as cellular colocalisation (standard IF practice).
How do I distinguish nonspecific chromogen from SLPI staining?
Run a secondary only control and inspect tissue pigment before assigning diffuse brown signal to SLPI (standard chromogenic IHC practice). Include a peroxidase block before DAB detection, since endogenous enzyme activity can generate chromogen independently of primary antibody binding (standard chromogenic IHC practice). Compare the suspect area with expected epithelial compartments: cervix glandular cells stain highly and bronchial respiratory epithelial cells stain moderately in the supplied tissue profile (HPA tissue IHC). If background persists, vary blocking or antibody concentration on adjacent sections while holding citrate pH 6.0 retrieval constant, and retain the condition with clearer cellular contrast (page retrieval rule; standard IHC practice).
What should I score when comparing SLPI across sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the tissue compartment and cell population before scoring, because SLPI is secreted and deposited protein may lie outside producing cells (UniProt P03973 subcellular annotation; standard IHC practice). For epithelial cells, record staining intensity and percent positive cells, then calculate an H-score from 0–300 if that scale fits the study design (standard IHC scoring practice). Normalize comparisons to the number of evaluable cells or epithelial area, and report the same denominator for every section (standard IHC scoring practice). Keep retrieval, imaging, and scoring thresholds constant, with a shared positive control to detect run variation (page retrieval rule; standard IHC practice).
Which patterns would make an apparent SLPI positive result doubtful?
A convincing result should fit the expected epithelial distribution, including high cervix glandular and nasopharynx goblet cell staining (HPA tissue IHC). Treat signal confined to cut edges, folds, or necrotic regions as suspect, and check secondary only and peroxidase controls before scoring it (standard IHC practice). Strong nuclear only staining is discordant with the reported cytoplasmic tissue pattern and Golgi cell imaging location (HPA tissue IHC; HPA subcellular). Extracellular material needs separate annotation rather than automatic rejection, because SLPI is secreted and tissue RNA and protein locations can differ (UniProt P03973 subcellular annotation; HPA tissue IHC reliability description).
Boster reagents
Best SLPI / Antileukoproteinase IHC Antibodies
A01682 has a real SLPI IHC image from mouse lung tissue (catalog: IHC image caption). Human and Mouse are listed as reactive species (catalog: reactivity); no IF image is supplied (catalog: IF image alts).
Real IHC data
Anti-Antileukoproteinase SLPI Antibody
Cat # A01682
A01682 will render with an IHC image of mouse lung tissue stained at 10 μg/mL (catalog: IHC image caption). It lists IHC-P and Human/Mouse reactivity (catalog: applications/reactivity), while the supplied IHC image documents mouse tissue only (catalog: IHC image caption).
Which to pick: Choose A01682 for tissue IHC-P: its application list includes IHC-P, and its image shows mouse lung tissue at 10 μg/mL; the fixative is unreported (catalog: applications/IHC image caption). No listed SKU has IF/ICC validation or an IF image, so there is no supported IF/ICC pick (catalog: applications/IF image alts). A01682 is the only cross-species candidate because Human and Mouse are listed as reactive, although the IHC image documents mouse tissue only; its host is Rabbit and its clone is unreported (catalog: reactivity/IHC image caption/host/clone).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P03973 (SLPI_HUMAN, Antileukoproteinase).
- Human Protein Atlas. SLPI tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. SLPI subcellular location (ICC-IF): Localized to the Golgi apparatus..
- Human Protein Atlas. SLPI antibody validation summary (2 antibodies).
- Secretory leukocyte protease inhibitor is an inducible antimicrobial peptide expressed in Staphylococcus aureus endophthalmitis. Mediators of inflammation 2007 — PMC2234354.
- Epithelial SLPI expression in severe inflammatory bowel disease relates to high IL-17 and neutrophil programming. JCI insight 2026 — PMC13135391.
- The level of secretory leukocyte protease inhibitor is decreased in metastatic head and neck squamous cell carcinoma. International journal of oncology 2011 — PMC4164221.
- Human papillomavirus infection in head and neck cancer: the role of the secretory leukocyte protease inhibitor. Oncology reports 2013 — PMC3658815.
- PubMed PMID:3533531 — UniProt-cited evidence.
- PubMed PMID:3640338 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for SLPI (Antileukoproteinase). Expected localisation Cytoplasmic staining in select epithelia (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A01682 at 10 μg/mL (the product's own IHC validation image is shown). Controls (HPA): positive Cervix (Glandular cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet A01682); 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 citrate buffer, pH 6.0 , 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 anti-SLPI, 10 μg/mL (datasheet A01682); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A01682); Caveat: Secreted SLPI may appear beyond producing cells (UniProt); Isoform / epitope: No isoforms reported; signal peptide 1–25 is cleaved (UniProt); Regulation: No expression regulator established in the record (UniProt). Evidence: UniProt P03973, HPA tissue IHC · Enhanced, HPA ICC-IF · Golgi apparatus., Datasheet A01682, PMC2234354, PMC4164221. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/SLPI/immunohistochemistry-ihc-guide.