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ARG1 / Arginase-1 · IHC design guide
Design Immunohistochemistry for ARG1
Plan ARG1 staining in paraffin sections using hepatocytes and bone marrow hematopoietic cells as positive references (HPA tissue IHC). This guide covers fixation, staining interpretation, and controls for the expected cytosolic signal (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
ARG1 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 | Cytosolic; neutrophil azurophil granules (UniProt) | |
| Staining pattern | High hepatocyte and marrow-cell staining; cytosolic expected (HPA tissue IHC; UniProt) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A01106) | |
| Positive control | Bone marrow+3 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) | |
| Caveat | Bone marrow staining varies across cell subsets (HPA tissue IHC) | |
| Regulation | Expressed in granuloma macrophages (UniProt) | |
| Isoform / epitope | Three isoforms; epitope differences are unspecified (UniProt) |
Section 1
Recommended ARG1 IHC & IF Protocols
The catalog antibody has an IHC-P protocol (datasheet: A01106). Two reports describe ARG1 staining of paraffin sections (PMC11648120; PMC10371158).
| Sample | Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet A01106) |
| Fixation | Image fixative and duration unreported (datasheet A01106); 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 A01106); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A01106) |
| Primary antibody | Rabbit anti-ARG1, 2-5 μg/ml (datasheet A01106) |
| Primary incubation | Overnight at 4 °C (datasheet A01106) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A01106) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | ARG1-positive staining in hematopoietic cells of bone marrow (HPA tissue IHC: High). HPA tissue profile: Selective expression in liver and subsets of bone marrow cells. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 (datasheet: A01106); neither published excerpt specifies a retrieval method (PMC11648120; PMC10371158).
Section 2
What Is the Expected ARG1 Staining Pattern?
ARG1 is cytosolic, with additional localization to neutrophil azurophil granules and no transmembrane segment (UniProt P05089: subcellular location and topology). In paraffin-section IHC, expect strong staining in hepatocytes and subsets of bone-marrow hematopoietic cells; spleen red-pulp cells and preleptotene spermatocytes show medium staining (HPA: tissue IHC). HPA rates the tissue pattern Enhanced, citing consistency between antibody staining and RNA expression (HPA: reliability).
| Strong cytoplasmic staining in hepatocytes or a subset of bone-marrow hematopoietic cells. | This matches the principal positive tissue pattern (HPA: High in hepatocytes and bone-marrow hematopoietic cells). Score the stained cell population and its cytoplasmic distribution together; a high-intensity field alone does not show that the expected cells carry the signal (general IHC interpretation). |
| Staining is chiefly nuclear or outlines cell membranes, with little cytoplasmic signal. | That distribution conflicts with the reported cytosolic location and absence of a transmembrane segment (UniProt P05089: location and topology). Treat it as suspect, then compare the slide with a known-positive tissue and appropriate detection controls before interpreting the compartment as ARG1 (general IHC practice). |
| Prominent staining appears in cells reported as negative, such as adipocytes or respiratory epithelial cells. | HPA reports ARG1 as not detected in those cell types (HPA: adipose tissue and bronchus IHC). Consider antibody cross-reactivity or detection-related signal, including endogenous activity with chromogenic detection (general IHC practice). Check cell identity and controls before treating unexpected staining as biological expression. |
| Weak, widespread color obscures both expected positive cells and surrounding tissue. | A diffuse field is difficult to reconcile with selective liver and bone-marrow expression (HPA: tissue IHC profile). It may reflect nonspecific antibody binding, inadequate blocking or washing, or detection background (general IHC practice). Judge the pattern against negative controls and the expected positive cell population. |
| No staining appears in hepatocytes on a technically readable section. | HPA reports high hepatocyte staining, making liver a useful positive reference (HPA: Liver, hepatocytes High). First check that the reference section, primary antibody, detection reagents, and run controls performed as intended (general IHC practice). The supplied sources do not identify ARG1-specific fixation sensitivity or an antigen-retrieval requirement. |
💡Expected ARG1 appearanceCall ARG1 positive when strong cytoplasmic staining is present in hepatocytes or the expected bone-marrow cell subset (HPA: High; UniProt P05089: cytosol); isolated nuclear, membrane-rim, or broadly diffuse color is suspect (UniProt P05089: location and topology; general IHC interpretation).
| Tissue and cell selection | Liver hepatocytes and subsets of bone-marrow hematopoietic cells are high; spleen red-pulp cells and preleptotene spermatocytes are medium (HPA: tissue IHC). Skin keratinocytes are low, so weak staining there is less decisive than a liver reference (HPA: Skin, keratinocytes Low). |
| Compartment and immune-cell context | Cytosol is the main reported location; neutrophils can also contain ARG1 in azurophil granules (UniProt P05089: subcellular location). UniProt also reports ARG1 in macrophages in mycobacterial granulomas and ILC2s during lung disease, so cell context matters when reviewing immune infiltrates (UniProt P05089: tissue specificity). |
| Antibody evidence and molecular variation | Five listed antibodies have Enhanced IHC validation, a category supported by independent antibodies or orthogonal data (HPA: antibody validation). UniProt lists three isoforms, but these payloads give no epitope mapping or isoform-specific IHC performance; do not infer which isoforms a chosen antibody detects (UniProt P05089: isoforms). |
| IF/ICC Q: Is a fluorescence pattern established here? | A: No ICC-IF images or HPA subcellular location are available (HPA: subcellular record). Cytosolic ARG1 is a location expectation from UniProt, not an HPA-validated ICC-IF staining pattern (UniProt P05089: location; HPA: subcellular record). |
| Situation | Likely cause | Next action |
|---|---|---|
| The liver positive reference has no visible hepatocyte signal. | A failed staining run or an unsuitable antibody setting is possible (general IHC practice); HPA reports hepatocytes as High (HPA: Liver IHC). | Review run controls and reagent performance, then optimize the IHC-validated antibody within its documented IHC conditions (general IHC practice). No ARG1-specific retrieval setting or dilution is supplied here. |
| Only nuclei or cell borders stain strongly. | The dominant compartment does not match reported cytosolic ARG1 or its lack of a transmembrane segment (UniProt P05089: location and topology). | Compare with hepatocyte staining and detection controls; assess whether counterstain, pigment, or nonspecific detection is being mistaken for target signal (general IHC practice). |
| Unexpected epithelial or adipocyte staining dominates the slide. | Those cell types are reported as not detected in the cited HPA tissues (HPA: bronchus respiratory epithelium; adipose adipocytes). Cross-reactivity or detection background is possible (general IHC practice). | Confirm the cell type and compare a negative tissue, a known-positive liver section, and appropriate detection controls before assigning ARG1 positivity (general IHC practice). |
| Brown color appears across much of a blood-rich section. | Chromogenic background, including endogenous enzyme activity, can complicate interpretation (general IHC practice); HPA describes a selective ARG1 tissue pattern (HPA: tissue IHC profile). | Examine the appropriate detection control and verify that the laboratory's endogenous-activity blocking step worked; score only recognizable cells with the expected distribution (general IHC practice). |
| Spleen or testis staining looks weaker than liver. | HPA reports medium staining in spleen red-pulp cells and preleptotene spermatocytes, versus high staining in hepatocytes (HPA: tissue IHC). | Compare the specified cell populations and compartments rather than demanding equal intensity across tissues (HPA: tissue IHC; general IHC interpretation). |
| An IF/ICC result is being used to confirm the IHC compartment. | HPA supplies no ICC-IF images or subcellular localization call for ARG1 (HPA: subcellular record). | Describe the IF/ICC observation as experimental, and use the cytosolic location as a UniProt-based expectation; do not label the fluorescence pattern HPA-validated (UniProt P05089: location; HPA: subcellular record). |
Experiment evidence
IHC & IF images showing ARG1 staining
A01106 · IHCIHC analysis of ARG1 using anti-ARG1 antibody (A01106). ARG1 was detected in a paraffin-embedded section of human liver cancer tissue. Heat
A01106 · IHCIHC analysis of ARG1 using anti-ARG1 antibody (A01106). ARG1 was detected in a paraffin-embedded section of mouse liver tissue. Heat mediate
M01106-5 · IHCHuman hepatocellular carcinoma was stained with anti-Arginase-1 rabbit antibody
M01106-5 · IHCHuman liver was stained with anti-Arginase-1 rabbit antibody
M01106-2 · IHCImmunohistochemical analysis of paraffin-embedded human liver, using Liver Arginase Antibody.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000118520-ARG1/tissue/cerebral+cortex#imid_21157683
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000118520-ARG1/tissue/colon#imid_21157601
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000118520-ARG1/tissue/liver#imid_21157602
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000118520-ARG1/tissue/kidney#imid_21157611
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for ARG1 IHC & IF
🧪Run liver first: hepatocytes should stain strongly (HPA: High in hepatocytes). Use adipose tissue as the negative tissue, with adipocytes expected to lack staining (HPA: Not detected in adipocytes); on the liver slide, assess morphologically identified non-hepatocyte cells for background, without assuming every such cell is ARG1-negative (HPA: High in hepatocytes; UniProt P05089: ARG1 also occurs in immune cells).
Positive control tissue: Bone marrow (Hematopoietic 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 ARG1; derive a cell-line control from the positive tissue's cell type (Hematopoietic cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control and a concentration-matched rabbit IgG isotype control alongside a validated ARG1-knockout biological negative (selected caption: rabbit primary antibody; standard IHC practice). Block endogenous peroxidase and assess endogenous biotin background in liver because the selected chromogenic workflow uses a biotinylated secondary, avidin–biotin complex, and DAB (selected IHC caption; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A01106 paraffin-section caption does not state the fixative (selected IHC caption). The demonstrated chromogenic workflow uses heat retrieval in EDTA at pH 8.0; that example does not establish that retrieval is required for every ARG1 antibody (selected IHC caption). The supplied evidence does not establish whether frozen sections or IF are easier; for liver IHC, check endogenous biotin background in this biotin-based detection workflow (selected IHC caption; standard IHC practice).
HPA tissue IHC evidence for ARG1
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 |
|---|---|---|---|---|
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Liver | Hepatocytes | High | Protein (IHC) | HPA → |
| Spleen | Cells in red pulp | Medium | Protein (IHC) | HPA → |
| Testis | Preleptotene spermatocytes | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced ARG1 IHC Tips
Troubleshoot ARG1 staining in paraffin sections by checking retrieval, cell identity and cytoplasmic localisation before comparing staining scores.
Which retrieval condition should I use when ARG1 staining is weak?
Start with heat-mediated retrieval in EDTA at pH 8.0 (datasheet A01106). The selected paraffin-section image used that condition before incubation with 2 μg/ml primary antibody overnight at 4°C, so reproduce those steps when investigating a weak result (caption A01106). Include a liver section with hepatocytes as a positive control and compare staining in the same run (HPA: High in hepatocytes; standard IHC practice). If the control remains weak, check retrieval heating and section adhesion, then assess alternative retrieval conditions as a documented optimisation rather than treating them as validated for this antibody (standard IHC practice).
How should I investigate weak staining after fixation?
The selected image documents a paraffin-embedded section but does not report its fixative, so target-specific fixation sensitivity is unknown (caption A01106). Record the fixative and processing history for each specimen, then compare sections processed under known conditions in the same staining run (standard IHC practice). Use heat-mediated EDTA retrieval at pH 8.0 and the documented 2 μg/ml primary concentration as starting conditions when assessing the difference (caption A01106). Include liver hepatocytes as a positive control; a weak control suggests a run or processing problem, while a strong control directs attention to specimen history and cellular composition (HPA: High in hepatocytes; standard IHC practice).
What ARG1 staining pattern should count as correctly localised?
Expect predominantly cytoplasmic staining because ARG1 is annotated in the cytosol and has no transmembrane segment (UniProt P05089 localisation and topology). In neutrophils, ARG1 can also occupy azurophil granules, so punctate cytoplasmic staining can fit the annotated localisation when cell identity supports it (UniProt P05089 localisation). Check the staining against morphology and a liver positive control, where hepatocytes show high expression (HPA: High in hepatocytes; standard IHC practice). Predominantly isolated nuclear or crisp cell-surface staining warrants review of counterstain, antibody background and detection before it is scored as ARG1 (UniProt P05089 localisation and topology; standard IHC practice).
Can this antibody distinguish ARG1 isoforms or modified epitopes?
ARG1 has 3 annotated isoforms, but the supplied antibody evidence does not establish which isoforms its epitope detects (UniProt P05089 isoforms; caption A01106). The protein is annotated as a 1–322 chain with no signal peptide, propeptide or transmembrane segment; those annotations alone cannot locate this antibody’s epitope (UniProt P05089 processing and topology). Several modified residues are listed, including phosphoserines at positions 62, 72 and 163, without evidence that they alter this staining (UniProt P05089 modified residues). Treat a staining difference as a difference in detected immunoreactivity until epitope mapping or orthogonal evidence supports an isoform-specific or modification-specific interpretation (standard IHC practice).
How can I assess ARG1 by multiplex IF alongside this IHC guide?
For a separate IF assay, pair ARG1 with a marker identifying the expected cell population, such as a hepatocyte or granulocyte marker, and assess overlap at the cellular level (HPA: High in hepatocytes; UniProt P05089 tissue specificity; standard IF practice). Choose a fluorophore channel after checking tissue autofluorescence and include single-stain controls to assess bleed-through (standard IF practice). ARG1 is cytosolic and has no transmembrane segment, so permeabilise cells sufficiently to access an intracellular epitope while preserving morphology (UniProt P05089 localisation and topology; standard IF practice). Optimise fixation and permeabilisation within that IF assay; the paraffin-section caption supplies no IF fixation condition (caption A01106; standard IF practice).
How do I reduce diffuse DAB or nonspecific ARG1 staining?
First inspect a no-primary control for signal arising from the detection system, and apply a peroxidase block before DAB development as part of routine chromogenic IHC (standard IHC practice). The selected image used 10% goat serum blocking, 2 μg/ml primary antibody overnight at 4°C, and a biotinylated secondary followed by SABC and DAB (caption A01106). If background persists, compare primary concentration and washing conditions while keeping retrieval at the documented EDTA pH 8.0 starting point (caption A01106; standard IHC practice). Judge whether residual colour follows expected hepatocyte cytoplasm or instead coats unrelated structures uniformly (HPA: High in hepatocytes; UniProt P05089 localisation; standard IHC practice).
How should I quantify ARG1 across heterogeneous tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and analysis area before scoring, then report the percentage of ARG1-positive cells or an H-score for cytoplasmic DAB intensity (UniProt P05089 localisation; standard IHC practice). For scattered immune cells, report positive-cell density per mm² of viable tissue and, when useful, the fraction of the identified cell population that is positive (standard IHC practice). Keep retrieval, staining batch, imaging and intensity thresholds consistent across specimens, using the documented EDTA pH 8.0 condition as the starting protocol (caption A01106; standard IHC practice). Normalise to the relevant viable cell population or tissue area, and exclude folds, edges and necrosis from the scored region (standard IHC practice).
How can I distinguish true ARG1 positivity from artefact?
Give greatest weight to cytoplasmic signal in morphologically identified cells; liver hepatocytes and subsets of bone marrow hematopoietic cells have high reported staining (UniProt P05089 localisation; HPA: High in hepatocytes and bone marrow hematopoietic cells). Granular cytoplasmic signal in neutrophils can also fit ARG1’s annotated azurophil-granule localisation (UniProt P05089 localisation). Review isolated nuclear staining, tissue-edge accentuation and necrotic areas against a no-primary control before calling them positive (UniProt P05089 localisation; standard IHC practice). Because the documented method uses biotinylated secondary, SABC and DAB, investigate detection-related colour in control sections and require plausible cell identity and compartment before assigning ARG1 expression (caption A01106; standard IHC practice).
Boster reagents
Best ARG1 / Arginase-1 IHC Antibodies
The catalog lists anti-ARG1 antibodies with IHC figures from human liver or liver cancer tissue, plus mouse and rat liver tissue (IHC captions); two antibodies also list IF among their applications (catalog: applications).
Real IHC data
Anti-liver Arginase/ARG1 Antibody ®
Cat # A01106
Real IHC data
Anti-Arginase-1 Rabbit Monoclonal Antibody
Cat # M01106-5
Real IHC data
Anti-Liver Arginase ARG1 Rabbit Monoclonal Antibody
Cat # M01106-2
A01106 has paraffin-section IHC figures from human liver cancer and mouse and rat liver (IHC captions); its listed reactivity also includes monkey (catalog: reactivity). M01106-5 has IHC figures from human hepatocellular carcinoma and human, mouse and rat liver (IHC captions), while M01106-2 has a paraffin-section IHC figure from human liver (IHC caption).
Which to pick: For tissue IHC on paraffin sections, choose A01106 for human, mouse or rat samples with directly pictured examples (A01106 IHC captions), or M01106-2 for human liver with a pictured paraffin-section example (M01106-2 IHC caption). For IF/ICC, M01106-2 lists both applications and is a rabbit monoclonal (catalog: M01106-2 applications and clonality); its supplied figure shows IHC only (M01106-2 IHC caption). For cross-species IHC and IF, M01106-5 is a rabbit monoclonal listed for human, mouse and rat (catalog: M01106-5 applications, clonality and reactivity); its IHC captions do not report the fixative or section processing.
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P05089 (ARGI1_HUMAN, Arginase-1).
- Human Protein Atlas. ARG1 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. ARG1 subcellular location (ICC-IF): Highest expression in Hep-G2: 4.5 nTPM.
- Human Protein Atlas. ARG1 antibody validation summary (5 antibodies).
- Human umbilical cord mesenchymal stem cells alleviate hypoxic-ischemia-induced white-matter injury in neonatal rats by regulating polarization of microglia. Scientific reports 2026 — PMC13066634.
- ARG1 Is a Potential Prognostic Marker in Metastatic Endometrial Cancer. Reproductive sciences (Thousand Oaks, Calif.) 2024 — PMC11648120.
- ARG1 is a potential prognostic marker in metastatic and recurrent endometrial cancer. Research square 2023 — PMC10371158.
- ARG1 Inhibition after Neonatal Hypoxic-Ischemic Brain Injury. Developmental neuroscience 2026 — PMC13044354.
- PubMed PMID:3540966 — UniProt-cited evidence.
- PubMed PMID:3174433 — UniProt-cited evidence.
- PubMed PMID:14574404 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for ARG1 (Arginase-1). Expected localisation Cytosolic; neutrophil azurophil granules (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A01106). Validated IHC antibody: A01106 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Bone marrow (Hematopoietic cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet A01106); 2. Fixation: Image fixative and duration unreported (datasheet A01106); 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 A01106); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A01106); 8. Primary antibody: Rabbit anti-ARG1, 2-5 μg/ml (datasheet A01106); 9. Primary incubation: Overnight at 4 °C (datasheet A01106). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Bone marrow staining varies across cell subsets (HPA tissue IHC); Isoform / epitope: Three isoforms; epitope differences are unspecified (UniProt); Regulation: Expressed in granuloma macrophages (UniProt). Evidence: UniProt P05089, HPA tissue IHC · Enhanced, HPA cell-line RNA · Highest expression in Hep-G2: 4.5 nTPM, Datasheet A01106, PMC11648120, PMC10371158. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/ARG1/immunohistochemistry-ihc-guide.