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CES1 / Liver carboxylesterase 1 · IHC design guide
Design Immunohistochemistry for CES1
Use hepatocytes as a positive reference when planning chromogenic CES1 staining in paraffin sections (HPA tissue IHC). The IHC-validated antibody M01741-1 has a recommended concentration of 2–5 µg/mL (datasheet: M01741-1); assess cytoplasmic staining by cell type (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CES1 Immunohistochemistry Experimental Design Guide
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before staining
| Expected localisation | Cytoplasmic tissue staining (HPA tissue IHC) | |
| Staining pattern | Hepatocyte, gallbladder gland and lung macrophage cytoplasm (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet M01741-1) | |
| Positive control | Appendix+4 more · see all | |
| Negative control | Bone marrow+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) | |
| Caveat | Score lung macrophages separately from other cells (HPA tissue IHC) | |
| Regulation | Intensity regulation not specified (UniProt) | |
| Isoform / epitope | 3 isoforms; epitope differences are unknown (UniProt) |
Section 1
Recommended CES1 IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet: M01741-1) with a published cynomolgus monkey brain IHC protocol (PMC12879735).
| Sample | Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet M01741-1) |
| Fixation | Image fixative and duration unreported (datasheet M01741-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet M01741-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet M01741-1) |
| Primary antibody | Mouse monoclonal (clone 3F10) anti-CES1, 2μg/ml (datasheet M01741-1) |
| Primary incubation | Overnight at 4 °C (datasheet M01741-1) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet M01741-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CES1-positive staining in endocrine cells of appendix (HPA tissue IHC: High). HPA tissue profile: Distinct cytoplasmic expression in liver and gall bladder as well as in lung and subsets of cells in gastrointestinal tract. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet: M01741-1); the published excerpt does not specify retrieval conditions (PMC12879735).
Section 2
What Is the Expected CES1 Staining Pattern?
CES1 is an endoplasmic reticulum lumen protein without a transmembrane segment; UniProt also reports cytoplasmic and lipid droplet localisation, with movement to droplets upon lipid loading (UniProt P23141 topology and subcellular location). In paraffin IHC, expect predominantly cytoplasmic staining in hepatocytes, gallbladder glandular cells, respiratory epithelium, lung macrophages and selected gastrointestinal endocrine cells (HPA: tissue IHC, Enhanced reliability).
| Strong cytoplasmic staining in hepatocytes, with tissue structure preserved (HPA: liver hepatocytes High; tissue IHC profile). | This is a suitable positive pattern for CES1 IHC (HPA: liver hepatocytes High). Compare cells within the section and the negative reagent control before judging intensity; these comparisons are general IHC practice, not a CES1 staining threshold. |
| Cytoplasmic signal appears in gallbladder glandular cells, bronchial respiratory epithelium or lung macrophages (HPA: each cell population High). | The expected positive cell depends on the tissue (HPA: tissue IHC). In lung, identify macrophages when interpreting a positive result; the HPA High entry names macrophages, whereas the bronchus High entry names respiratory epithelial cells (HPA: tissue IHC). |
| Nuclear-only, crisp membrane-only or widespread extracellular staining dominates the section. | These patterns conflict with the reported endoplasmic reticulum, cytoplasmic and lipid droplet locations and the lack of a transmembrane segment (UniProt P23141 topology and subcellular location). Treat the result as suspect and check detection controls before assigning CES1. |
| Cells listed as undetected stain as strongly as hepatocytes, or nearly every cell in a mixed tissue stains. | This raises concern for cross-reactivity or endogenous detection activity; it does not prove either cause (HPA: liver hepatocytes High; heart muscle cardiomyocytes and bone marrow hematopoietic cells Not detected). Check the exact cell type and controls; whole tissues are not universal negatives (HPA: tissue IHC). |
| A uniform chromogenic haze obscures cell boundaries, or known-positive hepatocytes show no discernible signal. | Haze prevents a reliable localisation call; absent hepatocyte signal leaves the stain unverified (HPA: liver hepatocytes High). In general IHC practice, background and signal failure require separate checks of controls, antibody concentration, retrieval and detection. |
💡Expected CES1 appearanceCall a positive result when distinct cytoplasmic staining is evident in hepatocytes or another HPA-listed High cell population; diffuse haze or predominantly nuclear or membrane staining is suspect (HPA: tissue IHC, Enhanced reliability; UniProt P23141 topology and subcellular location).
| Which tissue and cell should anchor scoring? | Use liver hepatocytes as a strong positive reference (HPA: hepatocytes High; liver tissue-enriched RNA). Gallbladder glandular cells, bronchial respiratory epithelial cells and lung macrophages are additional High populations (HPA: tissue IHC). Score the listed cells, since a tissue name alone does not specify every cell's CES1 status (HPA: tissue IHC). |
| How much confidence does the tissue pattern carry? | HPA rates tissue IHC reliability Enhanced because antibody staining is highly consistent with RNA expression (HPA: reliability description). HPA012023 and HPA046717 each have Enhanced IHC status (HPA: antibody validation). These ratings support the reference pattern; they do not identify the cause of an unexpected result in an individual section. |
| Can lipid droplets change the expected compartment? | UniProt places CES1 in the endoplasmic reticulum lumen and also reports cytoplasm and lipid droplets, with movement to droplets upon lipid loading (UniProt P23141 subcellular location). Interpret a possible droplet-associated pattern in the sample context; this record supplies no IHC criterion for proving droplet identity. |
| Do processing or isoforms change interpretation? | The precursor has a signal peptide at residues 1–17, and the annotated mature chain spans residues 18–567; three isoforms are listed (UniProt P23141 processing and isoforms). Antibody epitope and isoform coverage are not supplied here, so these annotations cannot explain a particular weak or absent stain. |
| IF/ICC Q: where should CES1 appear? | A: Endoplasmic reticulum localisation is supported by HPA ICC-IF, with images listed for A-549, Hep-G2 and U2OS (HPA: subcellular ICC-IF). This is an IF location reference; the paraffin IHC tissue pattern and its cell-specific scoring come from HPA tissue IHC (HPA: tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| No visible staining in hepatocytes used as the positive reference (HPA: liver hepatocytes High). | A failed staining run, unsuitable antibody conditions or weak detection is possible; the supplied records do not establish CES1-specific fixation sensitivity. | In general IHC practice, confirm the positive control and reagent controls, then review retrieval, antibody dilution and detection against the catalog antibody's IHC-P instructions; do not infer a CES1 fixation effect from HPA intensity. |
| Hepatocytes stain, but lung signal is assigned to the wrong cell population. | The HPA lung High call is for macrophages; respiratory epithelial cells are the High population in bronchus (HPA: tissue IHC). | Re-examine cell morphology and tissue region before scoring; compare like cell types across sections (general IHC practice). Report the observed cell type, since HPA's High entries do not imply uniform staining throughout lung. |
| Predominantly nuclear or sharply membrane-restricted staining appears. | That distribution conflicts with the annotated endoplasmic reticulum lumen, cytoplasm and lipid droplet locations and lack of a transmembrane segment (UniProt P23141 topology and subcellular location). | Check a liver positive control and a negative reagent control, then reassess antibody concentration and chromogen deposition (general IHC practice). Do not score compartmentally discordant staining as confirmed CES1. |
| Heart muscle cardiomyocytes or bone marrow hematopoietic cells show strong staining. | Those cell populations are listed as Not detected in HPA tissue IHC; unexpected signal could reflect cross-reactivity or endogenous detection activity, but the pattern alone cannot distinguish them (HPA: tissue IHC). | Check a negative reagent control for detection-related signal and compare an independently validated CES1 stain where available (general IHC practice). Record the specific cells stained rather than calling an entire tissue positive. |
| Brown haze covers cells and connective tissue, obscuring cytoplasmic detail. | Diffuse background can arise from nonspecific reagent binding or detection chemistry (general IHC practice); it cannot be attributed to CES1 expression from appearance alone. | Use a negative reagent control, inspect blocking and washing, and review antibody and detection reagent concentrations (general IHC practice). Re-score only when cell boundaries and cytoplasmic localisation are discernible. |
| Signal is weak in stomach glandular cells or other HPA Low populations. | A Low HPA call predicts less conspicuous staining than the High hepatocyte reference; it is not an assay failure by itself (HPA: stomach glandular cells Low; liver hepatocytes High). | Check hepatocytes in a parallel positive control before changing conditions (HPA: liver hepatocytes High; general IHC practice). Preserve the distinction between a weak expected population and a failed run when reporting the result. |
Experiment evidence
IHC & IF images showing CES1 staining
M01741-1 · IHCIHC analysis of Liver Carboxylesterase 1/CES1 using anti-Liver Carboxylesterase 1/CES1 antibody (M01741-1). Liver Carboxylesterase 1/CES1 wa
M01741-1 · IHCIHC analysis of Liver Carboxylesterase 1/CES1 using anti-Liver Carboxylesterase 1/CES1 antibody (M01741-1). Liver Carboxylesterase 1/CES1 wa
M01741-1 · IFIF analysis of Liver Carboxylesterase 1/CES1 using anti-Liver Carboxylesterase 1/CES1 antibody (M01741-1). Liver Carboxylesterase 1/CES1 was
A01741-1 · IHCIHC analysis of CES1 using anti-CES1 antibody (A01741-1). CES1 was detected in paraffin-embedded section of mouse kidney tissue . Heat media
A01741-1 · IHCIHC analysis of CES1 using anti-CES1 antibody (A01741-1). CES1 was detected in paraffin-embedded section of human lung cancer tissue. Heat m
A01741-1 · IFIF analysis of CES1 using anti-CES1 antibody (A01741-1). CES1 was detected in immunocytochemical section of HepG2 cells. Enzyme antigen retr
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000198848-CES1/tissue/cerebral+cortex#imid_19180163
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000198848-CES1/tissue/colon#imid_19186949
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000198848-CES1/tissue/liver#imid_19186942
HPA · GallbladderHuman Protein Atlas IHC, Gallbladder. Source: https://www.proteinatlas.org/ENSG00000198848-CES1/tissue/gallbladder#imid_19186926
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA046717; green = CES1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA046717; green = CES1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CES1 IHC & IF
🧪Run bronchus first and assess respiratory epithelial cells, which HPA scores High (HPA: bronchus, respiratory epithelial cells, High). Use bone marrow hematopoietic cells as the negative comparator (HPA: bone marrow, hematopoietic cells, Not detected); any internal negative cells on the bronchus slide should retain only the counterstain, but the supplied HPA row does not identify a specific negative cell population.
Positive control tissue: Appendix (Endocrine cells, HPA High)
Negative control tissue: Bone marrow (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CES1 in A-549, Hep-G2, U2OS, with annotated localisation: Endoplasmic reticulum (supported) (HPA subcellular).
Technical controls: Include no-primary (secondary-only) and concentration-matched mouse IgG isotype controls; the caption identifies a mouse primary but does not report its clonality (catalog caption: mouse primary). A CES1-knockout specimen processed alongside the test sections provides a biological negative; for this SABC/DAB method, block endogenous peroxidase and check for endogenous biotin background (catalog caption: SABC/DAB).
⚠️Feasibility: The selected SKU’s paraffin-section caption reports heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required under all conditions (catalog caption: EDTA retrieval). A target-specific fixation window or fixation effect is unreported, and the exact caption does not state a fixative (catalog caption: fixative not stated). No supplied matched protocol establishes that frozen sections or IF are easier; with chromogenic staining, distinguish bronchial pigment or other brown background from cell-associated DAB signal using the controls (catalog caption: DAB detection).
HPA tissue IHC evidence for CES1
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 |
|---|---|---|---|---|
| Appendix | Endocrine cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Colon | Endocrine cells | High | Protein (IHC) | HPA → |
| Duodenum | Endocrine cells | High | Protein (IHC) | HPA → |
| Gallbladder | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
| Cerebral cortex | Endothelial cells | Not detected | Protein (IHC) | HPA → |
| Endometrium | Cells in endometrial stroma | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CES1 IHC Tips
Troubleshoot CES1 staining in paraffin sections by checking retrieval, cell identity and subcellular pattern against the catalog image and reference expression data.
What should I change if CES1 staining is weak after antigen retrieval?
Start with heat mediated retrieval in EDTA at pH 8.0 for the catalog antibody (datasheet M01741-1). The selected paraffin section image used this retrieval before overnight incubation with 2 μg/mL primary antibody at 4°C (datasheet M01741-1). If staining remains weak, compare a modest range of heating and cooling times on matched sections, holding antibody concentration and detection constant; excessive heating can damage morphology (standard IHC practice). Use a liver section with hepatocytes as a positive reference, then assess whether the expected cytoplasmic pattern improves without diffuse tissue staining (HPA: High in liver hepatocytes; HPA: distinct cytoplasmic expression).
How should I troubleshoot fixation when CES1 staining varies between sections?
CES1 specific sensitivity to fixation is unknown: the selected tissue caption identifies a paraffin section but does not state its fixative (datasheet M01741-1). Record each specimen’s fixative, fixation duration and processing history, and compare sections with similar histories before changing retrieval or antibody concentration (standard IHC practice). Inspect morphology alongside staining, because poorly preserved or overprocessed areas can confound interpretation of cytoplasmic signal (standard IHC practice; HPA: distinct cytoplasmic expression). Keep the catalog’s EDTA pH 8.0 retrieval constant during the comparison, and use liver hepatocytes as a reference for whether staining remains detectable (datasheet M01741-1; HPA: High in liver hepatocytes).
Does punctate cytoplasmic CES1 staining fit its expected localisation?
CES1 is reported in the endoplasmic reticulum lumen and cytoplasm, and can move to lipid droplets upon lipid loading (UniProt P23141 subcellular location). HPA supports endoplasmic reticulum localisation and describes distinct cytoplasmic tissue staining, so assess puncta within the broader cellular context rather than scoring puncta alone (HPA: subcellular; HPA: tissue IHC). The protein has no annotated transmembrane segment, so a crisp plasma membrane outline would warrant checking background and antibody specificity (UniProt P23141 topology). Compare intact hepatocytes or lung macrophages with neighboring cells, and verify that punctate deposits do not follow section folds, edges or DAB precipitate (HPA: High in liver hepatocytes and lung macrophages; standard IHC practice).
Can the catalog stain distinguish CES1 isoforms or processed CES1?
CES1 has 3 annotated isoforms, a signal peptide at residues 1–17, and a mature chain spanning 18–567 (UniProt P23141 processing and isoforms). The supplied catalog caption does not identify the antibody epitope, so its staining cannot establish which isoform or processing state is detected (datasheet M01741-1). Check the antibody’s documented immunogen or epitope against the relevant sequences before making an isoform claim, then compare staining with an independent, epitope defined reagent if that distinction matters (standard antibody validation practice). Interpret altered staining cautiously because CES1 also has an annotated glycosylation site at residue 79 and a reported phosphoserine at 380; staining alone does not identify either modification (UniProt P23141 modified residues).
How can IF help verify cell identity and CES1 compartment staining?
For a separate IF experiment, multiplex CES1 with a validated marker for the expected hepatocyte or macrophage population, and check whether its signal occupies those cells (HPA: High in liver hepatocytes and lung macrophages). Choose a fluorophore and imaging channel that separate signal from the specimen’s measured autofluorescence, with single stain and no primary controls to assess bleed through and background (standard IF practice). CES1 is reported in the endoplasmic reticulum lumen and has no annotated transmembrane segment, so test permeabilisation sufficient to access an intracellular epitope once its location is known (UniProt P23141 topology and subcellular location). HPA lists ICC/IF images in A-549, Hep-G2 and U2OS, but those observations do not specify fixation or permeabilisation conditions for this antibody (HPA: subcellular; datasheet M01741-1).
How do I reduce diffuse DAB staining without losing CES1 signal?
The catalog image used 10% goat serum blocking, 2 μg/mL primary antibody overnight at 4°C, and biotinylated secondary detection with DAB (datasheet M01741-1). On matched sections, check a no primary control, quench endogenous peroxidase and assess whether a biotin based detection control is needed before adjusting primary concentration (standard chromogenic IHC practice). If background persists, titrate the primary and shorten DAB development while retaining the documented EDTA pH 8.0 retrieval as the starting condition (datasheet M01741-1; standard IHC practice). Compare cytoplasmic staining in hepatocytes against nearby tissue and exclude diffuse deposits that also appear in control sections (HPA: High in liver hepatocytes; HPA: distinct cytoplasmic expression; standard IHC practice).
What scoring method best captures variable CES1 staining across cells? ⚠ ANSWER MARKED FOR VERIFICATION
Score CES1 within prespecified cell populations and compartments: hepatocytes are a high expressing liver population, while lung macrophages can also stain strongly (HPA: High in liver hepatocytes and lung macrophages; HPA: distinct cytoplasmic expression). For cellular intensity, report the percentage of positive cells and an H-score calculated from the percentages at intensity levels 0–3, using identical thresholds across sections (standard IHC scoring practice). For sparse positive cells, report positive cell density per mm² of viable sampled tissue, with cell type recorded separately (standard quantitative pathology practice). Normalise counts to eligible cells or viable tissue area, and keep exposure, DAB development and region selection consistent between groups (standard IHC practice).
Which CES1 patterns suggest true signal rather than tissue artefact?
A credible CES1 pattern is intracellular and cytoplasmic, especially in liver hepatocytes or lung macrophages, with endoplasmic reticulum localisation supported by subcellular data (HPA: tissue IHC and subcellular; HPA: High in liver hepatocytes and lung macrophages). A sharp plasma membrane outline is less consistent with the reported luminal and cytoplasmic locations and absence of an annotated transmembrane segment (UniProt P23141 topology and subcellular location). Treat staining confined to cut edges, folds or necrotic regions as suspect, and compare it with an adjacent no primary control (standard IHC practice). In chromogenic detection, check endogenous peroxidase and biotin related signal before assigning weak DAB deposits to CES1 (standard IHC practice; datasheet M01741-1: biotinylated detection and DAB).
Boster reagents
Best CES1 / Liver carboxylesterase 1 IHC Antibodies
Anti-CES1 antibodies have paraffin-section IHC images from human and mouse tissues and IF/ICC images from HepG2 cells (catalog: image captions); both list human, mouse and rat reactivity (catalog: reactivity).
Real IHC data
Anti-Liver Carboxylesterase 1/CES1 Antibody ® (monoclonal, 3F10)
Cat # M01741-1
Real IHC data
Anti-Liver Carboxylesterase 1/CES1 Antibody ®
Cat # A01741-1
M01741-1 has IHC images from human liver cancer, tonsil and prostate cancer tissues and mouse lung, plus an IF/ICC image from HepG2 cells (M01741-1: image captions). A01741-1 has IHC images from mouse kidney and lung, human lung cancer and rat lung, plus an IF/ICC image from HepG2 cells (A01741-1: image captions).
Which to pick: For human tissue IHC, M01741-1 is a mouse monoclonal with paraffin-section images using EDTA retrieval at pH 8 (M01741-1: catalog and IHC captions). For IF/ICC, A01741-1 is a rabbit antibody with a HepG2 fluorescence image; its tissue IHC captions instead use citrate retrieval at pH 6 (A01741-1: catalog and image captions). Both list human, mouse and rat reactivity, with cross-species IHC images available for A01741-1; the captions do not report the tissue fixative (catalog: reactivity; A01741-1: IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P23141 (EST1_HUMAN, Liver carboxylesterase 1).
- Human Protein Atlas. CES1 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. CES1 subcellular location (ICC-IF): Localized to the endoplasmic reticulum..
- Human Protein Atlas. CES1 antibody validation summary (2 antibodies).
- CCL17-neutralizing and esterase-responsive core-shell microgels for endogenous Tregs recruitment and functional enhancement in myocardial infarction. Bioactive materials 2026 — PMC13292248.
- Ester Prodrug NLRP3 Inflammasome Inhibitor NT-0796 is Brain Active due to Activation by Local Expression of Carboxylesterase-1. ACS chemical neuroscience 2026 — PMC12879735.
- Nicotine-induced CHRNA5 activation modulates CES1 expression, impacting head and neck squamous cell carcinoma recurrence and metastasis via MEK/ERK pathway. Cell death & disease 2024 — PMC11522702.
- Carboxylesterase 1 family knockout alters drug disposition and lipid metabolism. Acta pharmaceutica Sinica. B 2023 — PMC9978993.
- PubMed PMID:1918003 — UniProt-cited evidence.
- PubMed PMID:8218228 — UniProt-cited evidence.
- PubMed PMID:8406473 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CES1 (Liver carboxylesterase 1). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet M01741-1). Validated IHC antibody: M01741-1 at 2μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Appendix (Endocrine cells); negative Bone marrow. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet M01741-1); 2. Fixation: Image fixative and duration unreported (datasheet M01741-1); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: EDTA pH 8.0 (datasheet M01741-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet M01741-1); 8. Primary antibody: Mouse monoclonal (clone 3F10) anti-CES1, 2μg/ml (datasheet M01741-1); 9. Primary incubation: Overnight at 4 °C (datasheet M01741-1). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Score lung macrophages separately from other cells (HPA tissue IHC); Isoform / epitope: 3 isoforms; epitope differences are unknown (UniProt); Regulation: Intensity regulation not specified (UniProt). Evidence: UniProt P23141, HPA tissue IHC · Enhanced, HPA ICC-IF · endoplasmic reticulum., Datasheet M01741-1, PMC12879735. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CES1/immunohistochemistry-ihc-guide.