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CHIT1 / Chitotriosidase-1 · IHC design guide
Design Immunohistochemistry for CHIT1
Plan chromogenic CHIT1 IHC on paraffin sections using the catalog antibody at 1:50–1:200 (datasheet: IHC). Compare staining with the cytoplasmic signal reported in subsets of spleen, bone marrow and lymph node cells (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CHIT1 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 in a subset of tissue cells (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic in subsets of spleen, marrow and lymph node cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Lymph node | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A03406) | |
| Caveat | Secreted CHIT1 may yield different RNA and protein tissue patterns (HPA tissue IHC) | |
| Regulation | Staining regulation unreported (UniProt) | |
| Isoform / epitope | 4 isoforms; epitope effects are unreported (UniProt) |
Section 1
Recommended CHIT1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is accompanied by a published rat cartilage CHIT1 protocol (PMC4194398).
| Sample | Paraffin-embedded human normal stomach tissue; fixative not specified (datasheet A03406) |
| Fixation | Image fixative and duration unreported (datasheet A03406); 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-CHIT1, 1:50-1:200 (datasheet A03406) |
| 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 | CHIT1-positive staining in germinal center cells of lymph node (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic expression in subset of cells in spleen, bone marrow and lymph node. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 HIER at 95–98 °C for 20 min (page retrieval); the published protocol also uses citrate pH 6.0 (PMC4194398).
Section 2
What Is the Expected CHIT1 Staining Pattern?
CHIT1 is a secreted protein with no transmembrane segment; a small proportion is lysosomal (UniProt Q13231). In paraffin-section IHC, expect cytoplasmic staining in a subset of cells in spleen, bone marrow and lymph node (HPA: tissue IHC, Enhanced reliability). HPA reports medium staining in lymph-node germinal center cells and low staining in splenic red-pulp and bone-marrow hematopoietic cells (HPA: tissue IHC).
| A subset of lymph-node germinal center cells shows medium cytoplasmic staining. | This matches the clearest supplied positive-cell example (HPA: lymph-node germinal center cells, Medium). Judge the stained cells and their cytoplasmic compartment, rather than expecting uniform staining throughout the section (HPA: subset expression). |
| Scattered cells in splenic red pulp or bone marrow show weak cytoplasmic staining. | A low-level result can fit the reference pattern: HPA reports Low in red-pulp cells and hematopoietic cells, within its broader cytoplasmic subset profile (HPA: tissue IHC). Weak signal needs comparison with background on the same slide (general IHC practice). |
| Staining appears mainly nuclear or as a continuous cell-membrane rim. | That distribution does not match HPA's cytoplasmic tissue pattern or the absence of a transmembrane segment (HPA: tissue IHC; UniProt Q13231 topology). Treat it as a possible artifact until controls and antibody specificity support it (general IHC practice). |
| Strong staining appears in adipocytes or bronchial respiratory epithelium, or color covers many cell types. | HPA reports CHIT1 as Not detected in those named cells (HPA: adipose tissue and bronchus IHC). Check for cross-reactivity, nonspecific binding or endogenous detection activity; the staining alone cannot distinguish these causes (general IHC practice). |
| There is no signal in lymph-node germinal center cells while the assay otherwise appears clean. | This conflicts with HPA's Medium positive example, but one negative section does not establish that CHIT1 is absent (HPA: lymph-node IHC; general IHC practice). Check tissue representation, detection performance and the antibody's IHC validation before interpreting a biological negative. |
💡Expected CHIT1 appearanceA convincing positive is subset-restricted cytoplasmic staining, clearest at Medium level in lymph-node germinal center cells; broad staining of HPA-negative cell types or dominant nuclear signal warrants investigation (HPA: tissue IHC).
| Secreted protein with a minor lysosomal fraction (UniProt Q13231). | Interpret the documented cytoplasmic staining as the tissue reference pattern (HPA: tissue IHC). Do not require a discrete lysosomal pattern or use diffuse extracellular color alone to identify CHIT1; neither is established as a diagnostic IHC pattern by the supplied HPA record. |
| Cell distribution and signal level vary across the supplied tissues (HPA: tissue IHC). | Lymph-node germinal center cells are Medium, while splenic red-pulp and bone-marrow hematopoietic cells are Low (HPA: tissue IHC). Compare the same named cells when judging a positive control; an entire tissue need not stain uniformly (HPA: subset expression). |
| HPA rates tissue staining Enhanced and lists two rabbit polyclonal antibodies with Enhanced and Supported IHC status (HPA: tissue IHC; HPA: antibodies). | These summaries support the reported tissue pattern, but do not validate every catalog antibody or every staining run (HPA: antibody-validation summaries). Confirm the antibody used is IHC validated and interpret its result against the named positive and negative cells (general IHC practice). |
| CHIT1 has a signal peptide at residues 1–21, four isoforms and one annotated glycosylation site at residue 100 (UniProt Q13231). | The mature chain is annotated as residues 22–466 (UniProt Q13231). The supplied record gives no antibody epitope or isoform recognition data, so these features cannot predict which species an individual IHC antibody detects or justify a retrieval change. |
| HPA lists tissue-enhanced RNA in bone marrow, lung and lymphoid tissue, and notes that secreted-protein RNA and tissue protein locations may differ (HPA: tissue IHC). | Use the reported protein staining to set slide expectations; RNA enrichment alone does not establish staining in every cell of those tissues (HPA: tissue IHC). In particular, the supplied HPA protein pattern remains cytoplasmic and subset restricted (HPA: tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| Lymph-node positive control has little or no staining. | The expected Medium germinal-center signal is missing (HPA: lymph-node IHC); section content or an IHC workflow step may be responsible (general IHC practice). | Verify that germinal centers are present, then check the IHC-validated antibody, retrieval settings and detection controls using the assay's documented procedure (general IHC practice). The supplied sources give no CHIT1-specific retrieval condition or fixation-sensitivity result. |
| All sections have diffuse chromogen or staining beyond cell boundaries. | This exceeds HPA's subset cytoplasmic pattern (HPA: tissue IHC). Nonspecific binding, incomplete washing or detection-system background are possibilities (general IHC practice). | Inspect a section processed without primary antibody; review blocking, wash steps and detection chemistry (general IHC practice). Do not score diffuse color as CHIT1-positive cells without a resolved cellular pattern (HPA: tissue IHC). |
| Adipocytes or bronchial respiratory epithelial cells stain prominently. | Both cell types are reported as Not detected (HPA: adipose tissue and bronchus IHC); cross-reactivity or endogenous activity is possible (general IHC practice). | Compare with a no-primary control and the named lymph-node positive cells; if enzyme-based detection is used, assess endogenous enzyme background with an appropriate detection control (general IHC practice). |
| Signal is mainly nuclear or outlines plasma membranes. | The compartment disagrees with the HPA cytoplasmic profile (HPA: tissue IHC); CHIT1 has no transmembrane segment (UniProt Q13231 topology). | Review morphology, counterstain and no-primary control, then reassess antibody specificity on a tissue with the documented cytoplasmic pattern (general IHC practice; HPA: lymph-node IHC). |
| Spleen or bone marrow looks negative despite a working lymph-node control. | HPA reports only Low staining in splenic red-pulp and bone-marrow hematopoietic cells, versus Medium in lymph-node germinal center cells (HPA: tissue IHC). | Examine the named cell populations and compare them with local background before scoring absence; report the tissue and cell type with the result (general IHC practice). Avoid treating equal intensity across these tissues as the expected pattern (HPA: tissue IHC). |
| Can an IF/ICC image be expected to show CHIT1 in a specific organelle? | HPA summarizes CHIT1 as Secreted but provides no main ICC-IF location or cell-line images; UniProt says only a small proportion is lysosomal (HPA: subcellular; UniProt Q13231). | Do not assign an IF/ICC organelle pattern from these records. Use the separate IF/ICC guide for that application; the supplied HPA record offers no image-based intracellular reference (HPA: subcellular). |
Experiment evidence
IHC & IF images showing CHIT1 staining
A03406 · IHCImmunohistochemistry of paraffin-embedded human normal stomach using CHIT1 antibody at dilution of 1:200 .Perform microwave antigen retrieva
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000133063-CHIT1/tissue/cerebral+cortex#imid_20028425
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000133063-CHIT1/tissue/colon#imid_20028335
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000133063-CHIT1/tissue/liver#imid_20028352
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000133063-CHIT1/tissue/kidney#imid_20028337
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CHIT1 IHC & IF
🧪Run lymph node first and look for staining in germinal center cells (HPA: Medium). Use adipose tissue adipocytes as the negative comparison (HPA: Not detected); on the lymph node slide, treat neighboring unstained cells as internal background controls without assuming a particular cell type is negative (HPA: only germinal center cells are specified).
Positive control tissue: Lymph node (Germinal center 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 CHIT1; derive a cell-line control from the positive tissue's cell type (Germinal center cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control, an immunoglobulin-matched isotype control appropriate to the primary antibody’s host species and clonality, and a CHIT1 knockout or validated peptide-block control (standard IHC practice). In lymph node, check endogenous peroxidase background in the chromogenic assay; assess autofluorescence if using IF (standard IHC/IF practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A03406 paraffin-section caption does not state a fixative (selected-SKU caption: fixative unreported). That caption uses microwave retrieval in 10 mM PBS at pH 7.2 with a 1:200 dilution, but does not establish whether retrieval is required across specimens (selected-SKU caption). There is no supplied evidence that frozen sections or IF/ICC are easier, and no ICC-IF cell-line images are listed (HPA: no ICC-IF images); endogenous peroxidase background in lymph node warrants a control (standard IHC practice).
HPA tissue IHC evidence for CHIT1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Secreted protein, tissue location of RNA and protein is expected to differ. External characterization data supports antibody staining.). 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 |
|---|---|---|---|---|
| Lymph node | Germinal center cells | 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 CHIT1 IHC Tips
Troubleshoot CHIT1 staining in paraffin-section IHC by checking retrieval, cellular distribution, controls and scoring against the available tissue evidence.
Which retrieval conditions should I try when CHIT1 staining is weak?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 minutes (page retrieval setting). If staining remains weak, compare a serial section retrieved by microwave in 10 mM PBS, pH 7.2, the condition reported for the catalog antibody in paraffin-embedded human normal stomach (A03406 caption). Keep antibody concentration and chromogen development constant while comparing retrieval conditions (standard IHC practice). Include a lymph node section with expected staining in germinal center cells to check whether the run worked (HPA tissue IHC). Record tissue damage alongside signal, since excessive heat can make staining harder to interpret (standard IHC practice).
Could fixation explain inconsistent CHIT1 staining between sections?
Target-specific fixation sensitivity is unknown: the catalog image identifies a paraffin-embedded section but reports no fixative (A03406 caption). Document the fixative and fixation time for each specimen, then compare sections processed under the same retrieval and detection conditions (standard IHC practice). A documented 10% neutral buffered formalin workflow can serve as a routine processing comparator, but it is not an established CHIT1 optimum (standard IHC practice). Check morphology before attributing a weak result to fixation, and include a positive tissue control in the same run (standard IHC practice; HPA tissue IHC: lymph node germinal center staining).
Where should convincing CHIT1 signal appear in tissue?
Look first for cytoplasmic staining in a subset of cells: that pattern is reported in spleen, bone marrow and lymph node (HPA tissue IHC). CHIT1 is secreted, with a small lysosomal proportion and no transmembrane segment, so extracellular signal needs separate interpretation from cell-associated staining (UniProt Q13231 subcellular location and topology). Germinal center cells in lymph node provide a reported medium signal reference; red-pulp cells in spleen and hematopoietic cells in bone marrow have reported low signal (HPA tissue IHC). Score cytoplasmic and extracellular staining separately, and check cell boundaries against the counterstain before assigning a positive cell (standard IHC practice).
How might CHIT1 processing or isoforms affect antibody interpretation?
Ask for the antibody's mapped epitope before claiming isoform coverage; the supplied product caption does not identify it (A03406 caption). CHIT1 has 4 listed isoforms, a signal peptide at residues 1–21, a GH18 domain at 22–388 and a chitin-binding domain at 417–466 (UniProt Q13231). Its listed glycosylation site is residue 100, but the supplied evidence does not show whether that site changes this antibody's staining (UniProt Q13231; A03406 caption). Isoform 3 lacks enzymatic activity, so a positive IHC signal alone cannot establish CHIT1 activity (UniProt Q13231; standard IHC interpretation).
How should I assess CHIT1 in a multiplex fluorescence experiment?
Treat fluorescence performance as unestablished for this antibody: the supplied product evidence is paraffin-section IHC, and HPA lists no ICC/IF images (A03406 caption; HPA subcellular). Pair CHIT1 with a macrophage marker to test a plausible cellular source, while evaluating other stained cells independently; cultured macrophages secrete CHIT1 (UniProt Q13231). Choose a spectrally separated, preferably far-red fluorophore after measuring tissue autofluorescence in an unstained section (standard IF practice). For an intracellular or lysosomal epitope, compare gentle permeabilisation with an otherwise matched unpermeabilised control; CHIT1 has a small lysosomal fraction (standard IF practice; UniProt Q13231).
How can I distinguish CHIT1 staining from chromogenic background?
Run a no-primary control and examine staining outside intact cells before changing the antibody concentration (standard IHC practice). For peroxidase and DAB detection, block endogenous peroxidase and compare the control's deposit with the test section; these are general chromogenic workflow steps (standard IHC practice). The catalog stomach image used a 1:200 antibody dilution, which provides a documented starting point for that specimen rather than a universal optimum (A03406 caption). If diffuse color persists, optimise blocking, washing and chromogen development one variable at a time, then reassess cytoplasmic signal against the tissue pattern (standard IHC practice; HPA tissue IHC).
What is a defensible way to score CHIT1 IHC? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and tissue compartment before scoring, because CHIT1 can be secreted as well as cell-associated (UniProt Q13231 subcellular location). Report the percentage of positive cells and an intensity-weighted H-score from 0–300, using intensity categories 0–3 with fixed thresholds across slides (standard IHC practice). If cell counts are more informative, report positive-cell density per mm² of viable tissue and normalise to the evaluated area or total cells in that compartment (standard IHC practice). Keep extracellular deposits and necrotic regions out of the cell score, and document how each was handled (standard IHC practice).
When should an apparent CHIT1-positive result be questioned?
Question a dominant nuclear or uniform surface pattern, since the supplied record places CHIT1 in secreted and lysosomal compartments without a transmembrane segment (UniProt Q13231). Compare the stained cell population with the reported subset pattern in lymphoid tissues, while recognising that secretion can separate protein location from its source cell (HPA tissue IHC and reliability description). Exclude section edges, necrosis and deposits reproduced in a no-primary control before calling a result positive (standard IHC practice). In peroxidase and DAB IHC, persistent color in that control warrants checking endogenous enzyme blocking and detection reagents before interpreting CHIT1 distribution (standard IHC practice).
Boster reagents
Best CHIT1 / Chitotriosidase-1 IHC Antibodies
A03406 has real CHIT1 IHC data from paraffin-embedded human normal stomach (A03406 image caption); listed reactivity covers human and mouse (catalog: A03406 reactivity).
Real IHC data
Anti-Chitotriosidase-1 CHIT1 Antibody
Cat # A03406
A03406 will render with an IHC image of paraffin-embedded human normal stomach stained at 1:200 (A03406 image caption). Its listed applications are IHC and WB, with human and mouse reactivity (catalog: A03406 applications/reactivity).
Which to pick: Choose A03406 for tissue IHC: this rabbit antibody lists IHC, and its own image shows paraffin-embedded human normal stomach after microwave retrieval in 10 mM PBS, pH 7.2 (catalog: A03406 host/applications; A03406 image caption); the fixative is unreported (A03406 image caption). For cross-species work, A03406 lists human and mouse reactivity, although its IHC image documents human tissue only (catalog: A03406 reactivity; A03406 image caption). No IF/ICC pick is supported because A03406 has no listed IF application, IF image or IF dilution (catalog: A03406 applications/IF fields).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q13231 (CHIT1_HUMAN, Chitotriosidase-1).
- Human Protein Atlas. CHIT1 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. CHIT1 subcellular location (ICC-IF): Secreted.
- Human Protein Atlas. CHIT1 antibody validation summary (2 antibodies).
- Expression of CHI3L1 and CHIT1 in osteoarthritic rat cartilage model. A morphological study. European journal of histochemistry : EJH 2014 — PMC4194398.
- Inhibition of Macrophage-Specific CHIT1 as an Approach to Treat Airway Remodeling in Severe Asthma. International journal of molecular sciences 2023 — PMC10003607.
- Pharmacological Inhibition of Chitotriosidase (CHIT1) as a Novel Therapeutic Approach for Sarcoidosis. Journal of inflammation research 2022 — PMC9529231.
- Myopathology and Immune Profile of Granulomatous Myositis in Sarcoid Myopathy. Neuropathology and applied neurobiology 2025 — PMC12421948.
- PubMed PMID:7592832 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:16710414 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CHIT1 (Chitotriosidase-1). Expected localisation Cytoplasmic in a subset of tissue cells (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A03406 at 1:50-1:200 (the product's own IHC validation image is shown). Controls (HPA): positive Lymph node (Germinal center cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human normal stomach tissue; fixative not specified (datasheet A03406); 2. Fixation: Image fixative and duration unreported (datasheet A03406); 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-CHIT1, 1:50-1:200 (datasheet A03406); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A03406); Caveat: Secreted CHIT1 may yield different RNA and protein tissue patterns (HPA tissue IHC); Isoform / epitope: 4 isoforms; epitope effects are unreported (UniProt); Regulation: Staining regulation unreported (UniProt). Evidence: UniProt Q13231, HPA tissue IHC · Enhanced, HPA ICC-IF · Secreted, Datasheet A03406, PMC4194398. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CHIT1/immunohistochemistry-ihc-guide.