This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
KLK1 / Kallikrein-1 · IHC design guide
Design Immunohistochemistry for KLK1
Plan KLK1 chromogenic IHC on paraffin sections using salivary glandular and pancreatic exocrine cells as reference sites (HPA tissue IHC). This guide covers fixation consistency, controls and scoring in light of KLK1 secretion and low staining–RNA consistency (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
KLK1 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 | Tissue-IHC subcellular compartment unestablished (HPA tissue IHC) | |
| Staining pattern | Salivary glandular and pancreatic exocrine cells; subcellular pattern unreported (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| 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 paraffin sections (standard IHC practice; not target-specific); KLK1-specific effects are unknown. | |
| Caveat | Secreted KLK1 may stain away from RNA-positive cells (HPA tissue IHC) | |
| Regulation | Staining regulation unreported (HPA tissue IHC) | |
| Isoform / epitope | 2 isoforms; mature chain starts at aa 25; epitope site unknown (UniProt) |
Section 1
Recommended KLK1 IHC & IF Protocols
The catalog antibody protocol is followed by three published KLK1 IHC protocols covering astrocytoma, mouse kidney, and prostate tissue (PMC4521496; PMC11432477; PMC8110393).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet PA1625); 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-KLK1, 0.5-1μg/ml (datasheet PA1625) |
| 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 | KLK1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: Medium). HPA tissue profile: Expressed mainly in salivary gland but also pancreas. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page retrieval); check staining against appropriate controls before optimizing.
Section 2
What Is the Expected KLK1 Staining Pattern?
KLK1 is a secreted protein with no transmembrane segment; UniProt gives no precise subcellular location (HPA: secreted; UniProt P06870 topology). In paraffin-section IHC, expect staining mainly in salivary glandular cells and also pancreatic exocrine glandular cells, both reported at Medium intensity (HPA tissue IHC). HPA rates its tissue IHC Approved, while noting low agreement with RNA and presumed off-target staining (HPA tissue IHC reliability).
| Salivary glandular cells stain at a moderate level, with similar staining in pancreatic exocrine glandular cells. | This matches the reported positive cell types and Medium staining level (HPA tissue IHC). Compare identifiable cells within each section; secreted KLK1 may extend beyond its cell of origin, so extracellular signal alone does not identify the producing cell (HPA: secreted). |
| A sharply nuclear or membrane-rim pattern dominates the glandular cells. | Treat the compartment assignment as suspect: HPA describes KLK1 as secreted, and UniProt reports no transmembrane segment or annotated subcellular location (HPA subcellular; UniProt P06870 topology). Recheck morphology and detection controls before calling a specific KLK1 pattern (standard IHC practice). |
| Adipocytes or bone-marrow hematopoietic cells stain as strongly as the expected glandular cells. | Those cell types were Not detected in HPA tissue IHC (HPA tissue IHC). Investigate cross-reactivity or endogenous detection activity before interpreting the stain; HPA explicitly notes presumed off-target binding in its reliability assessment (HPA tissue IHC reliability). |
| Colour spreads across glandular and nonglandular structures without clear cell boundaries. | A broad wash of signal cannot establish which cells contain KLK1, particularly for a secreted protein (HPA: secreted). Review the no-primary control and detection background, then score only anatomically identifiable staining (standard IHC practice). |
| Salivary gland and pancreatic exocrine cells show no discernible staining. | Both are reported at Medium staining in HPA tissue IHC, making them useful positive comparisons (HPA tissue IHC). A blank slide warrants checking section integrity, retrieval, antibody application and detection with controls; it does not by itself prove KLK1 absence (standard IHC practice). |
💡Expected KLK1 appearanceA persuasive positive result is discernible, approximately Medium staining in salivary glandular or pancreatic exocrine glandular cells (HPA tissue IHC); dominant nuclear rims, indiscriminate background or equally strong staining in HPA-negative cell types should trigger review (HPA subcellular; HPA tissue IHC; standard IHC practice).
| Secretion and precursor processing (HPA: secreted; UniProt P06870 processing). | UniProt annotates a signal peptide at 1–18, propeptide at 19–24 and mature chain at 25–262 (UniProt P06870 processing). Interpret cell-associated and possible extracellular staining in that context; the supplied sources do not establish an exact IHC compartment (HPA subcellular; UniProt P06870). |
| Isoform expression (UniProt P06870 tissue specificity). | UniProt lists 2 isoforms and reports isoform 2 expression in several tissues, including pancreas and salivary glands (UniProt P06870). The supplied evidence gives no antibody epitope or isoform-specific IHC pattern, so a stained section cannot identify which isoform contributed (UniProt P06870; HPA tissue IHC). |
| Strength of tissue-pattern evidence (HPA tissue IHC reliability). | HPA calls the IHC result Approved but reports low antibody–RNA consistency and presumed off-target staining (HPA tissue IHC reliability). Its observed cell patterns guide control selection; they do not make every stained structure KLK1-specific (HPA tissue IHC reliability). |
| Glycosylation annotations (UniProt P06870 glycosylation). | UniProt lists 6 glycosylation sites (UniProt P06870). Neither supplied source links those sites to an IHC staining change or a fixation effect, so do not use them to explain a weak or absent section signal (UniProt P06870; HPA tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected glandular cells are blank in both positive tissues. | A failed staining run is possible; HPA reports Medium signal in both salivary and pancreatic glandular cells (HPA tissue IHC). | Check section morphology, antibody application, retrieval and detection against a concurrently processed positive control (standard IHC practice). |
| The no-primary control develops colour. | The signal may arise from the detection system or endogenous activity rather than primary-antibody binding (standard IHC practice). | Verify blocking and detection reagents, then repeat with a clean no-primary control before scoring KLK1 (standard IHC practice). |
| Staining is strongest in adipocytes or marrow hematopoietic cells. | HPA reports these cells as Not detected and flags presumed off-target binding (HPA tissue IHC). | Compare matched sections with the expected glandular positives and detection controls; withhold a KLK1 call for unsupported cell staining (HPA tissue IHC; standard IHC practice). |
| Diffuse extracellular colour obscures glandular boundaries. | Secreted KLK1 can complicate assigning a signal to a cell of origin; the exact IHC compartment is unreported (HPA: secreted; HPA tissue IHC). | Score identifiable glandular cells separately from extracellular deposits and review background controls before assigning localisation (standard IHC practice). |
| Kidney tubules stain weakly while salivary gland stains moderately. | This difference is compatible with HPA’s Low tubular and Medium salivary glandular observations (HPA tissue IHC). | Use the salivary section to assess run performance; avoid treating weak kidney staining alone as a failed assay (HPA tissue IHC; standard IHC practice). |
| Can IF/ICC confirm a specific KLK1 compartment? | HPA calls KLK1 secreted but provides no main subcellular location or ICC-IF image-bearing cell lines (HPA subcellular). | Treat IF/ICC localisation as exploratory and assess it with appropriate controls; the supplied evidence does not validate a specific IF/ICC pattern (HPA subcellular; standard IF practice). |
Experiment evidence
IHC & IF images showing KLK1 staining
PA1625 · IHCAnti-Kallikrein 1 antibody, PA1625, IHC(P) IHC(P): Human Pancreatic Cancer Tissue
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000167748-KLK1/tissue/cerebral+cortex#imid_16484619
HPA · Salivary glandHuman Protein Atlas IHC, Salivary gland. Source: https://www.proteinatlas.org/ENSG00000167748-KLK1/tissue/salivary+gland#imid_16484583
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000167748-KLK1/tissue/colon#imid_16484561
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000167748-KLK1/tissue/liver#imid_16484546
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for KLK1 IHC & IF
🧪Run pancreas first: exocrine glandular cells should stain (HPA: Pancreas, exocrine glandular cells, Medium). Use adipose tissue as a negative, with adipocytes expected to be unstained (HPA: Adipose tissue, adipocytes, Not detected); on the pancreas slide, assess adjacent nonglandular cells as internal background controls rather than assuming every cell is KLK1-negative.
Positive control tissue: Adrenal gland (Glandular cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for KLK1; 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, a nonimmune isotype control matched to the primary antibody’s host species and clonality, and a KLK1 knockout specimen or immunizing-peptide block where available (standard IHC specificity controls). For chromogenic pancreas IHC, block endogenous peroxidase and check for endogenous biotin if using biotin-based detection (standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected PA1625 pancreatic-cancer IHC-P caption does not state a fixative (selected-SKU caption). Retrieval dependency is unreported in the supplied evidence; optimize antigen retrieval with the IHC-validated antibody (standard IHC-P practice). The supplied evidence does not establish that frozen sections or IF are easier; because KLK1 is secreted, assess possible luminal staining separately from cellular staining (HPA subcellular summary: Secreted).
HPA tissue IHC evidence for KLK1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low consistency between antibody staining and RNA expression data. Secreted protein, tissue location of RNA and protein is expected to differ. Presumed off target binding observed and disregarded.). 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 | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Colon | Glandular cells | Medium | Protein (IHC) | HPA → |
| Pancreas | Exocrine glandular cells | Medium | Protein (IHC) | HPA → |
| Rectum | Glandular cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Cerebral cortex | Endothelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced KLK1 IHC Tips
Troubleshoot KLK1 staining in paraffin sections by checking retrieval, cell type, staining pattern and controls before comparing chromogenic signal across samples.
How should I retrieve KLK1 in paraffin sections when glandular staining is weak?
Start with citrate buffer at pH 6.0 for heat-induced retrieval at 95–98 °C for 20 min (page retrieval rule). Run a salivary gland or pancreas control alongside the sample, because both show KLK1 staining in glandular cells (HPA tissue IHC). Keep section thickness, cooling and chromogenic development consistent when comparing retrieval runs (standard IHC practice). If staining remains weak, check the control, antibody incubation and detection reagents before changing retrieval conditions (standard IHC practice). Record any alternative retrieval condition separately; its effect on this antibody is not established by the supplied caption (PA1625 IHC(P) caption).
Could fixation explain weak or uneven KLK1 staining?
KLK1-specific sensitivity to fixative type or fixation duration is unknown from the supplied evidence (PA1625 IHC(P) caption: fixative not stated). Record the actual fixative and time for each specimen, then compare sections processed under matched conditions (standard IHC practice). If a control stains but the sample does not, inspect tissue preservation, section adhesion and retrieval consistency before attributing the result to fixation (standard IHC practice). Compare intact glandular areas with nearby damaged areas on the same slide, and repeat with a matched control if staining varies sharply (standard IHC practice). The pancreatic cancer tissue caption establishes an IHC(P) image, but gives no fixation condition to reproduce (PA1625 IHC(P) caption).
Where should KLK1 staining appear, and how should luminal signal be interpreted?
Evaluate glandular cells and adjacent luminal material separately: KLK1 is described as secreted, while UniProt gives no subcellular location (HPA subcellular; UniProt P06870). Its sequence has a signal peptide at residues 1–18 and no transmembrane segment, supporting a secretory context without proving a precise staining compartment (UniProt P06870). Salivary gland and pancreatic exocrine glandular cells provide useful tissue-pattern references (HPA tissue IHC). A luminal deposit alone cannot identify the cell that produced the protein, so annotate cellular and extracellular staining independently (HPA tissue IHC: secreted-protein caveat; standard IHC practice). Check morphology and an appropriate negative tissue before accepting diffuse extracellular chromogen as specific (standard IHC practice).
Can epitope processing or KLK1 isoforms change the IHC pattern?
Check the antibody's stated immunogen or epitope before interpreting discrepant sections; the supplied caption does not identify that region (PA1625 IHC(P) caption). KLK1 has 2 isoforms, and its precursor loses a signal peptide at residues 1–18 and a propeptide at 19–24 (UniProt P06870). An epitope in a removed segment may behave differently from one in the mature chain, but this antibody's epitope cannot be assigned here (UniProt P06870; PA1625 IHC(P) caption). Six annotated glycosylation sites provide another reason to document epitope placement without assuming they alter this antibody's staining (UniProt P06870). Compare specimens only after confirming that the chosen reagent and detection conditions are the same (standard IHC practice).
How can I investigate KLK1 localisation with multiplex IF?
Treat IF as a separately optimised application: the supplied PA1625 image documents IHC(P), and HPA lists no cell lines with KLK1 ICC/IF images (PA1625 IHC(P) caption; HPA subcellular). Pair KLK1 with a marker validated for the glandular cell population being examined, since salivary and pancreatic glandular staining is reported by tissue IHC (HPA tissue IHC; standard IF practice). Choose a fluorophore in a channel with low measured tissue autofluorescence and include single-colour and no-primary controls (standard IF practice). Select permeabilisation only after checking whether the antibody recognises an intracellular or accessible extracellular epitope; that epitope is unspecified here (PA1625 IHC(P) caption; standard IF practice). Assess cellular and luminal fluorescence separately because KLK1 is secreted (HPA subcellular).
How do I distinguish KLK1 signal from chromogenic background?
Include a no-primary control and inspect endogenous peroxidase activity before assigning brown chromogen to KLK1 (standard IHC practice). Apply a peroxidase block when using enzyme-based detection, then keep DAB development matched across comparison slides; these are general workflow steps (standard IHC practice). Review reagent background, folds and section edges at the same microscope settings as the candidate signal (standard IHC practice). A salivary gland or pancreas control helps identify the expected glandular pattern, while HPA reports presumed off-target binding in its tissue assessment (HPA tissue IHC). If broad staining persists in a tissue reported as undetected, such as cervical glandular cells, investigate specificity before scoring it as KLK1 (HPA tissue IHC; standard IHC practice).
How should I score KLK1 across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the analysis region and cell population before scoring, and keep those definitions consistent across sections (standard IHC practice). For glandular cells, record the percentage positive at each intensity from 0–3 and calculate an H-score from 0–300, or report percentage positive alone (standard IHC practice). If extracellular staining matters, measure its stained area or optical density separately and normalise it to the assessed tissue area in mm² (standard IHC practice; HPA subcellular: secreted). Exclude folds, necrosis and section edges by a predefined rule, and use matched control tissue to monitor staining runs (standard IHC practice). Report cellular and luminal results separately because secreted protein can differ from the tissue location of its RNA (HPA tissue IHC).
When is a KLK1-positive IHC result convincing?
Look for reproducible glandular staining with an appropriate control: HPA reports KLK1 mainly in salivary gland and also in pancreas (HPA tissue IHC). Interpret luminal or extracellular signal cautiously because KLK1 is secreted, and do not require protein staining to match local RNA expression (HPA subcellular; HPA tissue IHC). Diffuse signal confined to section edges or necrotic areas warrants review against morphology and no-primary controls (standard IHC practice). Investigate staining dominated by an unexpected cell type or residual endogenous peroxidase signal before calling it positive (standard IHC practice). HPA rates its tissue staining Approved but notes low RNA–protein consistency and presumed off-target binding, so the staining pattern alone is insufficient for a specificity claim (HPA tissue IHC).
Boster reagents
Best KLK1 / Kallikrein-1 IHC Antibodies
PA1625 has a real IHC(P) image from human pancreatic cancer tissue (catalog image caption); Human, Mouse, and Rat reactivity is listed (catalog: reactivity).
Real IHC data
Anti-Kallikrein 1/KLK1 Antibody ®
Cat # PA1625
PA1625 is the only SKU shown, with an IHC(P) image of human pancreatic cancer tissue (catalog image caption). Its application list includes IHC, but no IF/ICC application or image is listed (catalog: applications; IF image alts).
Which to pick: For paraffin-section IHC, choose PA1625 at 0.5–1 μg/ml (catalog: IHC-P dilution); its image shows human pancreatic cancer tissue, and the fixative is unreported (catalog image caption). No IF/ICC pick is supported by the listed applications or images (catalog: applications; IF image alts). For cross-species planning, PA1625 lists Human, Mouse, and Rat reactivity, but its IHC(P) image documents human tissue only; clonality is unreported (catalog: reactivity; image caption; clone).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P06870 (KLK1_HUMAN, Kallikrein-1).
- Human Protein Atlas. KLK1 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. KLK1 subcellular location (ICC-IF): Secreted.
- Human Protein Atlas. KLK1 antibody validation summary (1 antibodies).
- Prognostic significance of multiple kallikreins in high-grade astrocytoma. BMC cancer 2015 — PMC4521496.
- KLK1 as an Epithelial-Specific Brake Inhibits Colorectal Tumorigenesis by Suppressing B1R-Mediated Fibroblast Phenotypic Transition. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 2025 — PMC12622486.
- Tissue Kallikrein-1 Suppresses Type I Interferon Responses and Reduces Depressive-Like Behavior in the MRL/lpr Lupus-Prone Mouse Model. International journal of molecular sciences 2024 — PMC11432477.
- Human Tissue Kallikrein 1 Is Downregulated in Elderly Human Prostates and Possesses Potential In Vitro Antioxidative and Antifibrotic Effects in Rodent Prostates. Oxidative medicine and cellular longevity 2021 — PMC8110393.
- PubMed PMID:3004571 — UniProt-cited evidence.
- PubMed PMID:2898948 — UniProt-cited evidence.
- PubMed PMID:2686621 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for KLK1 (Kallikrein-1). Expected localisation Tissue-IHC subcellular compartment unestablished (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: PA1625 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 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 PA1625); 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-KLK1, 0.5-1μg/ml (datasheet PA1625); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across paraffin sections (standard IHC practice; not target-specific); KLK1-specific effects are unknown.; Caveat: Secreted KLK1 may stain away from RNA-positive cells (HPA tissue IHC); Isoform / epitope: 2 isoforms; mature chain starts at aa 25 ; epitope site unknown (UniProt); Regulation: Staining regulation unreported (HPA tissue IHC). Evidence: UniProt P06870, HPA tissue IHC · Approved, HPA ICC-IF · Secreted, Datasheet PA1625, PMC4521496, PMC11432477. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/KLK1/immunohistochemistry-ihc-guide.