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TPP1 / Tripeptidyl-peptidase 1 · IHC design guide
Design Immunohistochemistry for TPP1
Plan paraffin-section IHC for TPP1 using its lysosomal tissue staining profile and cell-type controls (HPA tissue IHC). The guide also flags how maturation can affect epitope selection (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
TPP1 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 | Lysosomal staining in tissue (HPA tissue IHC) | |
| Staining pattern | Lysosomal staining in glandular, ciliated and glial cells (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet PB9899) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image PB9899) | |
| Caveat | Staining varies by cell type and tissue (HPA tissue IHC) | |
| Regulation | Regulation not specified (UniProt) | |
| Isoform / epitope | 2 isoforms; maturation removes residues 1–195, so check the epitope (UniProt) |
Section 1
Recommended TPP1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet: PB9899) and published chromogenic TPP1 IHC methods for endometrial sections (PMC7734757) and mouse brain sections (PMC4268109) provide starting conditions.
| Sample | Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet PB9899) |
| Fixation | Image fixative and duration unreported (datasheet PB9899); 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 PB9899); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet PB9899) |
| Primary antibody | Rabbit anti-TPP1, 0.5-1μg/ml (datasheet PB9899) |
| Primary incubation | Overnight at 4 °C (datasheet PB9899) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9899) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | TPP1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Ubiquitous expression in lysosomes. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet: PB9899); the published endometrial method uses citrate retrieval (PMC7734757).
Section 2
What Is the Expected TPP1 Staining Pattern?
TPP1 is a soluble lysosomal protease with no transmembrane segment (UniProt O14773: function and topology). In paraffin sections, expect cytoplasmic puncta in many cell types, including glandular cells and glia with high observed staining (HPA: ubiquitous lysosomal expression; high in adrenal glandular cells and caudate glia). HPA rates the tissue IHC pattern Enhanced, indicating consistency with RNA expression (HPA: tissue IHC reliability).
| Discrete cytoplasmic puncta in adrenal glandular cells or caudate glia, with little nuclear signal (HPA: high in both cell types). | This fits the reported lysosomal pattern (HPA: ubiquitous expression in lysosomes; UniProt O14773: lysosome). Score the cells and puncta seen on the slide; HPA's High category does not set a universal staining intensity for every section (HPA: tissue IHC levels). |
| Predominantly uniform nuclear, surface-rim, or extracellular staining, without convincing cytoplasmic puncta. | The dominant compartment conflicts with the reported lysosomal pattern and lack of a transmembrane segment (HPA: lysosomal profile; UniProt O14773: topology). Treat it as suspect and review morphology, controls, and detection background before assigning TPP1 positivity (general IHC practice). |
| Strong staining confined to adipocytes or soft-tissue fibroblasts while expected positive cells remain unstained. | HPA reports TPP1 as Not detected in those cell types (HPA: adipocytes; soft-tissue fibroblasts). Cross-reactivity or endogenous detection activity is possible; a Not detected reference is a comparison point, not proof that every specimen must be negative (general IHC interpretation). |
| Widespread diffuse color obscures cell boundaries and puncta across the section. | The distribution cannot establish lysosomal localization (HPA: lysosomal profile). Consider nonspecific antibody binding, endogenous enzyme activity, or chromogen background, and compare with the appropriate detection control before scoring (general chromogenic IHC practice). |
| No signal in a section containing adrenal glandular cells or caudate glia. | This conflicts with HPA's High observations in those cell types (HPA: adrenal glandular cells; caudate glia). First assess tissue preservation, retrieval, antibody application, and detection with a known-positive control; absence in one run does not establish biological loss (general IHC practice). |
💡Expected TPP1 appearanceA credible positive shows cell-associated cytoplasmic lysosomal puncta in HPA-high glandular cells or glia, with intensity judged against controls; dominant nuclear color or broad cell-free deposits are suspect (HPA: high in adrenal glandular cells and caudate glia; HPA: lysosomal profile; general IHC interpretation).
| Lysosomal localization and topology (UniProt O14773; HPA: tissue IHC profile) | Interpret granular cytoplasmic staining in cell context; a membrane-only pattern has weak support because UniProt lists no transmembrane segment (UniProt O14773: topology). |
| Cell-specific reference levels (HPA: tissue IHC) | High staining is reported in bronchial and fallopian-tube ciliated cell bodies, while adipocytes are Not detected (HPA: named cell types). Use cell identity when comparing regions; these categories do not prescribe an exact optical density. |
| Precursor processing (UniProt O14773: chains) | TPP1 has a signal peptide at residues 1–19, propeptide at 20–195, and mature chain at 196–563 (UniProt O14773: processing). Antibody epitope location is unspecified here, so this record cannot predict which processed form the IHC-validated antibody detects. |
| Glycosylation and isoforms (UniProt O14773) | Five glycosylation sites and two isoforms are listed (UniProt O14773: features). Their effects on this antibody's section staining cannot be inferred without an epitope map or comparative validation; do not explain a negative slide from these features alone. |
| Melanosome annotation (UniProt O14773: subcellular location) | TPP1 was identified by mass spectrometry in stage I–IV melanosome fractions (UniProt O14773: melanosome note). This does not establish a distinctive melanosomal chromogenic pattern in the supplied tissue IHC observations (HPA: lysosomal tissue profile). |
| IF/ICC Q: Is the IHC pattern an IF localization control? | A: No IF localization is provided: HPA lists no main ICC-IF location or cell-line images, and neither listed antibody has ICC validation (HPA: subcellular record; HPA037709 and HPA044868 validation). Assess IF on its own guide page. |
| Situation | Likely cause | Next action |
|---|---|---|
| Positive tissue lacks visible puncta despite intact morphology. | The result disagrees with HPA's High examples, but the supplied sources do not identify a TPP1-specific fixation or retrieval failure (HPA: adrenal glandular cells; caudate glia). | Check antibody and detection steps against their validated instructions; review retrieval and a known-positive section as general paraffin-IHC controls (general IHC practice). |
| Color is concentrated in nuclei or along cell surfaces. | Dominant localization differs from the lysosomal profile and soluble topology (HPA: lysosomal expression; UniProt O14773: no transmembrane segment). | Compare a detection-only control and inspect whether cytoplasmic puncta persist after background is excluded (general IHC practice); withhold a positive call if the discordant pattern dominates. |
| Adipocytes or soft-tissue fibroblasts appear strongly positive. | Both are listed as Not detected, so the result may reflect cross-reactivity or detection background (HPA: adipocytes; soft-tissue fibroblasts; general IHC interpretation). | Check staining in an HPA-high cell type on the same run and review detection controls before treating the unexpected cells as TPP1-positive (HPA: high in adrenal glandular cells; general IHC practice). |
| Brown deposits cover tissue-free areas or obscure cell boundaries. | A deposit outside interpretable cells cannot support the reported lysosomal distribution (HPA: lysosomal profile); chromogen precipitation or nonspecific detection is possible (general chromogenic IHC practice). | Review reagent cleanliness, washes, and a detection-only control, then score only clearly cell-associated staining (general IHC practice). |
| Glial staining varies between hippocampus and caudate. | HPA reports Low in hippocampal glia and High in caudate glia (HPA: tissue IHC). Regional differences alone therefore do not establish assay failure. | Record region and cell type separately, and compare matching regions across slides before interpreting intensity differences (HPA: glial levels; general IHC scoring practice). |
| Puncta are suggested in IF, but their identity is uncertain. | The supplied HPA subcellular record has no ICC-IF images or assigned main location; listed antibodies lack ICC validation (HPA: subcellular record; HPA037709 and HPA044868 validation). | Treat IF localization as unverified by these data and consult the separate IF/ICC guide for its controls and assessment (HPA: ICC-IF record). |
Experiment evidence
IHC & IF images showing TPP1 staining
PB9899 · IHCIHC analysis of TPP1 using anti-TPP1 antibody (PB9899). TPP1 was detected in a paraffin-embedded section of human lung cancer tissue. Heat m
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000166340-TPP1/tissue/cerebral+cortex#imid_9218896
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000166340-TPP1/tissue/colon#imid_9218822
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000166340-TPP1/tissue/liver#imid_9218823
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000166340-TPP1/tissue/kidney#imid_9218824
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for TPP1 IHC & IF
🧪Run cerebellum first and look for staining in Bergmann glia (HPA: cerebellum, Bergmann glia, High). Use adipose tissue as a negative comparator (HPA: adipocytes, Not detected); cells without signal on the cerebellar slide should show background staining, but the supplied HPA row does not establish a named internal negative cell type.
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for TPP1; derive a cell-line control from the positive tissue's cell type (Glandular cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary secondary-only control, concentration-matched irrelevant rabbit IgG, and a confirmed TPP1-knockout section as a biological negative (catalog caption: rabbit primary and goat anti-rabbit IgG; standard IHC practice). For SABC/DAB detection, quench endogenous peroxidase and assess endogenous biotin background; in cerebellum, distinguish neural lipofuscin pigment from chromogen (catalog caption: SABC/DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window and fixation effect are unreported, and the selected PB9899 paraffin-section caption does not state its fixative (catalog caption: fixative not stated). The caption uses heat retrieval in EDTA at pH 8.0, but does not establish a retrieval requirement for cerebellum (catalog caption: EDTA pH 8.0; lung cancer section). The supplied evidence does not establish whether frozen sections or IF/ICC are easier; neural lipofuscin may complicate interpretation of cerebellar staining (HPA subcellular: no ICC-IF image cell lines; standard IHC/IF practice).
HPA tissue IHC evidence for TPP1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High 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 |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Ciliated cells (cell body) | High | Protein (IHC) | HPA → |
| Caudate | Glial cells | High | Protein (IHC) | HPA → |
| Cerebellum | Bergmann glia - cytoplasm/membrane | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Cervix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Ovary | Ovarian stroma cells | Not detected | Protein (IHC) | HPA → |
| Soft tissue | Fibroblasts | Not detected | Protein (IHC) | HPA → |
| Vagina | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced TPP1 IHC Tips
Use the catalog antibody’s paraffin section result as the starting point, then judge staining against TPP1’s lysosomal localisation and documented cell patterns.
Which retrieval condition should I try first for TPP1 paraffin section IHC?
Start with heat mediated antigen retrieval in EDTA at pH 8.0 for paraffin section IHC (datasheet PB9899). The selected image used this condition before incubation with 1 μg/ml primary antibody overnight at 4°C (datasheet PB9899). If staining is weak, vary heating duration in small steps while keeping EDTA and pH constant, and inspect morphology after each change (standard IHC practice). Compare each trial with a reference section processed in the same run, since excessive retrieval can damage tissue and make punctate staining difficult to assess (standard IHC practice).
How should I assess whether fixation is affecting TPP1 staining?
The selected paraffin section caption does not state its fixative, so target specific fixation sensitivity cannot be determined from it (datasheet PB9899). Record the fixative, fixation duration and tissue handling for each specimen before comparing TPP1 intensity across samples (standard IHC practice). If a suspected fixation effect appears, process matched sections with the same EDTA pH 8.0 retrieval and antibody incubation, changing only the fixation condition under evaluation (datasheet PB9899; standard IHC practice). Assess tissue preservation alongside staining intensity, and avoid treating a weak section as evidence of low TPP1 expression until processing differences have been considered (standard IHC practice).
What staining pattern fits TPP1 in chromogenic IHC?
Look for a granular intracellular pattern compatible with lysosomes, rather than assigning diffuse staining alone to TPP1 (UniProt O14773 localisation; HPA tissue IHC profile). TPP1 is also reported in melanosome fractions, so pigment containing cells require careful separation of chromogen from native pigment (UniProt O14773 localisation; standard IHC practice). Use cell morphology and a paired section without primary antibody to assess whether apparent granules come from detection chemistry or tissue material (standard IHC practice). Broadly cytoplasmic colour can obscure discrete granules when DAB development is excessive; compare a shorter development with the reference section before interpreting localisation (standard IHC practice).
Can processing or isoforms explain inconsistent TPP1 staining?
TPP1 has 2 reported isoforms, and its precursor contains a signal peptide, propeptide and mature chain, so epitope position matters when comparing staining results (UniProt O14773 sequence and processing). The mature chain spans residues 196–563, while the propeptide spans 20–195 (UniProt O14773 processing). Five annotated glycosylation sites lie within the mature chain, but the supplied antibody caption does not identify its epitope (UniProt O14773 glycosylation; datasheet PB9899). Check the antibody’s documented immunogen or epitope before attributing a difference to an isoform, cleavage or glycosylation, and compare sections under identical retrieval conditions (standard IHC practice).
How can IF help resolve ambiguous TPP1 staining in tissue sections?
For a separate IF experiment, multiplex TPP1 with a validated marker for the expected cell type, such as ciliated cells in bronchus or glia in caudate (HPA tissue IHC; standard IF practice). Choose fluorophores after checking autofluorescence in an unstained section, and include single colour controls to assess channel bleed through (standard IF practice). TPP1 is lysosomal and has no transmembrane segment; access to a luminal epitope may require permeabilisation, but the antibody’s epitope is unspecified (UniProt O14773 localisation and topology; datasheet PB9899). Optimise permeabilisation against preserved puncta and cell morphology, then compare the IF distribution with chromogenic IHC on matched sections (standard IF/IHC practice).
What should I check when TPP1 DAB staining appears diffuse or widespread?
First compare a section processed without primary antibody and check endogenous peroxidase blocking, because either detection background or residual enzyme activity can produce DAB colour (standard IHC practice). The selected protocol used 10% goat serum blocking, a biotinylated secondary antibody and a streptavidin biotin detection system (datasheet PB9899). With that detection system, assess whether endogenous biotin contributes to background using an appropriate detection control (standard IHC practice). TPP1 expression is described as ubiquitous in lysosomes, so widespread staining alone does not establish an artefact; judge signal by cellular pattern, intensity and controls together (HPA tissue IHC profile; standard IHC practice).
How should I score TPP1 IHC across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and tissue region before scoring, since the HPA profile reports different staining levels among cell types (HPA tissue IHC). Within those regions, record the percentage of positive cells and staining intensity, then calculate an H-score if graded intensity is reproducible (standard IHC practice). For a punctate readout, positive cell density per mm² can be useful when tissue area varies; report the threshold and compartment used (standard IHC practice). Normalise counts to evaluable cells or intact tissue area, exclude necrotic regions, and keep retrieval, DAB development and image settings consistent across comparisons (standard IHC practice).
How do I distinguish a credible TPP1 positive from artefact?
A credible signal should fit an intracellular lysosomal pattern and the morphology of the stained cells (UniProt O14773 localisation; HPA tissue IHC profile). High staining is reported in bronchial ciliated cells and caudate glia, while adipocytes are listed as not detected; use these cell patterns as context, not absolute controls (HPA tissue IHC). Treat staining limited to section edges or necrotic areas cautiously, and check whether it persists in a no primary control (standard IHC practice). Also evaluate pigment and endogenous peroxidase before assigning dark deposits to TPP1, particularly when the expected granular localisation cannot be resolved (standard IHC practice).
Boster reagents
Best TPP1 / Tripeptidyl-peptidase 1 IHC Antibodies
PB9899 is a human-reactive IHC antibody with an image showing TPP1 staining in a paraffin-embedded human lung cancer section (catalog applications/reactivity; PB9899 IHC caption).
Real IHC data
Anti-TPP1 Antibody ®
Cat # PB9899
PB9899 lists IHC for human samples (catalog applications/reactivity). Its IHC image shows staining in a paraffin-embedded human lung cancer section; no IF image is supplied (PB9899 IHC caption; catalog IF image list).
Which to pick: Choose PB9899 for human paraffin-section IHC: its image documents EDTA retrieval at pH 8.0 and primary antibody at 1 μg/ml (PB9899 IHC caption). The fixative is unreported, so the caption does not establish fixation (PB9899 IHC caption). No SKU in this payload is listed for IF/ICC or species beyond human, and PB9899 has no clone designation (catalog applications/reactivity/clone field). The selected PB9899 tissue-IHC caption documents paraffin sections, but does not specify the fixative (selected-SKU IHC image PB9899).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O14773 (TPP1_HUMAN, Tripeptidyl-peptidase 1).
- Human Protein Atlas. TPP1 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. TPP1 subcellular location (ICC-IF): Highest expression in HTERT-RPE1: 231.9 nTPM.
- Human Protein Atlas. TPP1 antibody validation summary (2 antibodies).
- Tripeptidyl peptidase I promotes human endometrial epithelial cell adhesive capacity implying a role in receptivity. Reproductive biology and endocrinology : RB&E 2020 — PMC7734757.
- Intra-arterial delivery of AAV vectors to the mouse brain after mannitol mediated blood brain barrier disruption. Journal of controlled release : official journal of the Controlled Release Society 2014 — PMC4268109.
- Targeting Telomere Shelterin Protein TPP1 with Elbasvir: Induction of Autophagy and Suppression of Esophageal Cancer Tumorigenesis. Anti-cancer agents in medicinal chemistry 2025 — PMC13621370.
- Comparison of the amyloid plaque proteome in Down syndrome, early-onset Alzheimer's disease, and late-onset Alzheimer's disease. Acta neuropathologica 2025 — PMC11742868.
- PubMed PMID:9295267 — UniProt-cited evidence.
- PubMed PMID:9653647 — UniProt-cited evidence.
- PubMed PMID:12975309 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for TPP1 (Tripeptidyl-peptidase 1). Expected localisation Lysosomal staining in tissue (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet PB9899). Validated IHC antibody: PB9899 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet PB9899); 2. Fixation: Image fixative and duration unreported (datasheet PB9899); 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 PB9899); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet PB9899); 8. Primary antibody: Rabbit anti-TPP1, 0.5-1μg/ml (datasheet PB9899); 9. Primary incubation: Overnight at 4 °C (datasheet PB9899). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image PB9899); Caveat: Staining varies by cell type and tissue (HPA tissue IHC); Isoform / epitope: 2 isoforms; maturation removes residues 1–195, so check the epitope (UniProt); Regulation: Regulation not specified (UniProt). Evidence: UniProt O14773, HPA tissue IHC · Enhanced, HPA cell-line RNA · Highest expression in HTERT-RPE1: 231.9 nTPM, Datasheet PB9899, PMC7734757, PMC4268109. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/TPP1/immunohistochemistry-ihc-guide.