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DEFA4 / Defensin alpha 4 · IHC design guide
Design Immunohistochemistry for DEFA4
Plan DEFA4 IHC in paraffin sections using bone marrow hematopoietic cells as a high-staining reference (HPA tissue IHC) and the IHC-validated antibody at 1:100–1:300 (datasheet: A06846). Assess cytoplasmic staining in a subset of lymphoid cells (HPA tissue IHC), while accounting for the secreted peptide (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
DEFA4 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 | Cytoplasm in a subset of lymphoid cells (HPA tissue IHC) | |
| Staining pattern | A subset of lymphoid cells shows cytoplasmic staining (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Bone marrow+2 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 | Secreted protein: RNA and protein locations may differ (HPA tissue IHC) | |
| Regulation | Signal may vary with neutrophil abundance (UniProt) | |
| Isoform / epitope | No isoforms; processing may alter epitopes; no membrane side (UniProt) |
Section 1
Recommended DEFA4 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by one published DEFA4 protocol using paraffin-embedded renal biopsies (PMC7494931).
| Sample | Paraffin-embedded human heart tissue; fixative not specified (datasheet A06846) |
| Fixation | Image fixative and duration unreported (datasheet A06846); 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-DEFA4, 1:100 - 1:300 (datasheet A06846) |
| 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 | DEFA4-positive staining in hematopoietic cells of bone marrow (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in a subset of lymphoid cells. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page antigen-retrieval setting); the article does not specify retrieval conditions (PMC7494931).
Section 2
What Is the Expected DEFA4 Staining Pattern?
DEFA4 is a secreted peptide stored in neutrophil granules; expect cytoplasmic staining in relevant hematopoietic cells, with strongest tissue staining in bone marrow (UniProt P12838; HPA: High in bone marrow hematopoietic cells). HPA also reports cytoplasmic staining in a subset of lymphoid cells and rates its tissue IHC evidence Enhanced (HPA: tissue IHC). DEFA4 has no transmembrane segment, so a membrane outline is not its expected pattern (UniProt P12838 topology).
| Distinct cytoplasmic signal in bone marrow hematopoietic cells, with less intense staining in selected lymphoid cells. | This fits the reported High bone marrow signal and Medium signal in lymph node non-germinal center cells and splenic red-pulp cells (HPA: tissue IHC). Granule-associated staining is consistent with storage of mature DEFA4 in neutrophil granules (UniProt P12838). |
| Predominantly nuclear staining or a continuous membrane outline. | Neither pattern fits the reported cytoplasmic tissue signal or secretory-vesicle location; DEFA4 has no transmembrane segment (HPA: tissue IHC; UniProt P12838 topology). Treat the pattern as suspect and compare it with a matched negative control before interpreting it as DEFA4. |
| Strong signal in cells reported as unstained, such as appendix glandular cells. | HPA reports DEFA4 as Not detected in appendix glandular cells (HPA: tissue IHC). Consider antibody cross-reactivity or endogenous chromogenic activity, both general IHC explanations, and assess the staining with a no-primary control (standard IHC practice). |
| Diffuse color across many cell types or extracellular spaces, without a discernible cellular pattern. | A broadly diffuse result does not reproduce HPA's selective cytoplasmic pattern (HPA: tissue IHC). Extracellular material alone cannot establish a producing cell because DEFA4 is secreted (UniProt P12838; HPA: secreted-protein caveat). Review controls and background before scoring individual cells. |
| No visible signal in bone marrow hematopoietic cells. | This conflicts with HPA's High bone marrow staining and UniProt's reported expression in neutrophils and bone marrow (HPA: tissue IHC; UniProt P12838). First establish that the section and detection controls worked; an absent signal alone does not establish absent DEFA4. |
💡Expected DEFA4 appearanceCall a section positive when selected hematopoietic cells show discernible cytoplasmic staining, strongest in bone marrow; broad nuclear, membrane-outline, or appendix glandular-cell staining is suspect (HPA: tissue IHC; UniProt P12838 topology).
| Tissue and cell context | Bone marrow hematopoietic cells provide the clearest reported positive context (High); lymph node non-germinal center cells and splenic red-pulp cells are Medium (HPA: tissue IHC). Compare like cell populations when judging intensity. |
| Secretion and granule storage | DEFA4 is secreted and stored as mature peptide in neutrophil granules (UniProt P12838). HPA cautions that the tissue locations of protein and RNA can differ for secreted proteins; use the observed cellular IHC pattern when scoring a section (HPA: tissue IHC). |
| Precursor processing and topology | The 97-aa precursor has a signal peptide at residues 1–19 and annotated propeptide processing, with no transmembrane segment (UniProt P12838). These annotations support a secretory interpretation but do not identify the epitope recognized by a particular IHC antibody. |
| Evidence for the antibody and for IF/ICC | HPA rates tissue IHC reliability Enhanced and lists antibody HPA051266 as IHC Enhanced (HPA: tissue IHC; HPA: antibodies). Its subcellular record lists no ICC-IF images or main cellular location, so that IHC rating does not establish an IF/ICC staining pattern (HPA: subcellular). |
| Situation | Likely cause | Next action |
|---|---|---|
| Bone marrow positive control is blank. | The result disagrees with reported High staining in bone marrow hematopoietic cells (HPA: tissue IHC); the cause cannot be assigned from the blank section alone. | Confirm tissue identity and detection-control performance, then review the antibody dilution and retrieval conditions used for the IHC run (standard IHC practice). |
| Color appears even when primary antibody is omitted. | Primary-independent staining can arise from endogenous detection activity or detection-reagent background (standard chromogenic IHC practice). | Address the activity appropriate to the detection system and reassess blocking and wash steps; compare the corrected no-primary control with the test section (standard IHC practice). |
| Signal covers nearly every cell or obscures cell boundaries. | That distribution differs from HPA's cytoplasmic staining in a subset of lymphoid cells (HPA: tissue IHC). Excess nonspecific staining is one possible general IHC cause (standard IHC practice). | Review primary-antibody concentration, blocking, and washes; judge specificity against a tissue and cell type reported as Not detected (standard IHC practice; HPA: tissue IHC). |
| Apparent positivity is confined to extracellular material. | DEFA4 is secreted, so extracellular signal by itself does not identify the cells that produced it (UniProt P12838; HPA: secreted-protein caveat). | Record extracellular and cellular signal separately, and require a credible cytoplasmic pattern in expected cells for a cellular positive call (HPA: tissue IHC). |
| A nucleus or glandular epithelium is the main stained structure. | Nuclear staining conflicts with the reported cytoplasmic pattern; appendix glandular cells are reported Not detected (HPA: tissue IHC). Cross-reactivity or detection background remains possible (standard IHC practice). | Check the no-primary control and compare with expected bone marrow staining before assigning the signal to DEFA4 (HPA: tissue IHC; standard IHC practice). |
| Can the IHC pattern be used as the expected IF/ICC result? | HPA's subcellular entry says secreted but provides no ICC-IF images or main cellular location (HPA: subcellular). | Use the separate IF/ICC guide for that application; describe this page's cytoplasmic tissue pattern as IHC evidence, without treating it as IF/ICC validation (HPA: tissue IHC; HPA: subcellular). |
Experiment evidence
IHC & IF images showing DEFA4 staining
A06846 · IHCImmunohistochemistry analysis of Defensin α4 antibody in paraffin-embedded human heart tissue.
A06846-1 · IHCImmunohistochemistry (IHC) analyzes of Defensin α4 (D27) pAb in paraffin-embedded human colorectal carcinoma tissue at 1:50.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000164821-DEFA4/tissue/cerebral+cortex#imid_14444376
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000164821-DEFA4/tissue/colon#imid_14445050
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000164821-DEFA4/tissue/liver#imid_14445071
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000164821-DEFA4/tissue/kidney#imid_14444771
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for DEFA4 IHC & IF
🧪Run bone marrow first; hematopoietic cells should stain (HPA: High in bone marrow hematopoietic cells). Use adipose tissue as the negative tissue (HPA: Not detected in adipocytes); on the bone marrow slide, assess morphologically identified nonhematopoietic cells as internal negative 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 DEFA4; 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 matched isotype control for a monoclonal primary, or host-matched nonimmune IgG for a polyclonal primary; use DEFA4-knockout material, if available, as a biological negative. For chromogenic bone marrow IHC, block endogenous peroxidase and check background on the no-primary slide (standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported in the supplied evidence, and the selected A06846 paraffin-section caption does not report a fixative (A06846 caption). Antigen-retrieval dependency is also unreported; optimize retrieval against the positive and negative controls (standard IHC practice). Neither frozen sections nor IF/ICC is established as easier here; interpret granular cellular staining and possible extracellular signal in light of DEFA4 storage in neutrophil granules and secretion (UniProt P12838 subcellular).
HPA tissue IHC evidence for DEFA4
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High consistency between antibody staining and RNA expression data. Secreted protein, tissue location of RNA and protein is expected to differ.). 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 → |
| Lymph node | Non-germinal center cells | Medium | Protein (IHC) | HPA → |
| Spleen | Cells in red pulp | 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 DEFA4 IHC Tips
Troubleshoot DEFA4 staining in paraffin sections by checking retrieval, cell identity, granular localisation and controls before interpreting chromogenic signal.
How should I retrieve DEFA4 in paraffin sections when staining is weak?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 minutes (page retrieval rule). If signal remains weak, compare a longer or shorter heating interval on serial sections while keeping the buffer and detection conditions constant (standard IHC practice). Check a bone marrow control for staining in hematopoietic cells before changing the retrieval conditions again (HPA: High in bone marrow hematopoietic cells). Evaluate both signal and tissue preservation, because DEFA4 is stored as mature peptide in neutrophil granules and may also be secreted (UniProt P12838 localisation and processing).
Can I infer the best fixative for DEFA4 from the available tissue image?
No DEFA4-specific fixation sensitivity is established by the supplied evidence; the selected A06846 image identifies paraffin-embedded human heart but does not state its fixative (selected tissue-IHC caption: A06846). Record the actual fixative, fixation duration and processing history for each specimen before comparing staining (standard IHC practice). Test matched sections under the same citrate pH 6.0, 95–98 °C, 20-minute retrieval conditions when evaluating a fixation change (page retrieval rule). Include a bone marrow control in each comparison, and judge signal alongside morphology rather than inferring fixation effects from tissue expression patterns (HPA: High in bone marrow hematopoietic cells; standard IHC practice).
Where should convincing DEFA4 chromogenic staining appear in a tissue section?
Prioritise discrete cytoplasmic staining in the appropriate cells: DEFA4 is stored as mature peptide in neutrophil granules and is also secreted (UniProt P12838 localisation and processing). HPA reports cytoplasmic expression in a subset of lymphoid cells, with High staining in bone marrow hematopoietic cells (HPA: tissue IHC profile and bone marrow). Compare cellular signal with local extracellular staining, since a secreted protein can appear away from its site of synthesis (HPA: secreted-protein reliability note). Predominantly nuclear staining or a uniform outline around every cell warrants review of the control sections and detection chemistry before assigning it to DEFA4 (UniProt P12838 localisation; standard IHC practice).
How do precursor processing and epitope placement affect DEFA4 IHC interpretation?
DEFA4 has a 97-amino-acid precursor, a signal peptide at residues 1–19, and annotated propeptide regions at 20–63 and 97 (UniProt P12838 processing). The record lists 0 isoforms, 0 glycosylation sites and no transmembrane segment (UniProt P12838 isoforms, glycosylation and topology). Check the catalog antibody’s stated immunogen or epitope before assuming that staining reports precursor and stored mature peptide equally (UniProt P12838 processing; standard IHC practice). If epitope information is unavailable, describe the readout as antibody-reactive DEFA4 staining and compare its cellular distribution with an appropriate control (standard IHC practice; UniProt P12838 localisation).
How can IF help assess DEFA4 localisation alongside chromogenic IHC?
On the separate IF/ICC workflow, pair DEFA4 with a validated neutrophil marker to test cell identity, because the mature peptide is stored in neutrophil granules (UniProt P12838 localisation). Choose fluorophores after checking unstained tissue autofluorescence, and use single-stain controls to distinguish bleed-through from colocalisation (standard IF practice). For an intracellular granular epitope, include a permeabilisation condition; for an accessible extracellular epitope, assess staining without permeabilisation as well (UniProt P12838 localisation and topology; standard IF practice). Interpret IF against the chromogenic section’s cellular pattern, but do not assume identical sensitivity across detection methods (standard IHC/IF practice; HPA: cytoplasmic expression in a subset of lymphoid cells).
What should I check when DEFA4 staining looks diffuse or widespread?
First compare the suspect section with a no-primary control and inspect whether colour follows cells or extends across edges, folds and damaged areas (standard IHC practice). Check endogenous peroxidase blocking and the chromogen development step when diffuse colour persists in the control (standard chromogenic IHC practice). Because DEFA4 is secreted as well as stored in neutrophil granules, extracellular signal needs cautious interpretation rather than automatic rejection (UniProt P12838 localisation). Compare the pattern with a bone marrow control and review primary antibody concentration using the catalog instructions; HPA reports High staining in bone marrow hematopoietic cells (HPA: bone marrow; standard IHC practice).
How should I score DEFA4 staining across sections with different cell composition? ⚠ ANSWER MARKED FOR VERIFICATION
Define the analysis compartment and cell population before scoring, because DEFA4 is stored in neutrophil granules and HPA describes cytoplasmic staining in a subset of lymphoid cells (UniProt P12838 localisation; HPA: tissue IHC profile). Report the percentage of positive cells or positive-cell density per mm², and record staining intensity separately if using an H-score (standard IHC scoring practice). Normalise cell counts to the relevant nucleated-cell population or measured tissue area, and keep thresholds and imaging settings consistent across sections (standard IHC quantification practice). Exclude folds, edges and necrotic regions by a prespecified rule, then report extracellular staining separately from cellular positivity (standard IHC quantification practice; UniProt P12838 secreted localisation).
How can I separate genuine DEFA4 staining from section artefact?
A credible positive pattern aligns with cellular cytoplasm or granules in relevant cells: DEFA4 is stored in neutrophil granules, while HPA reports cytoplasmic staining in a subset of lymphoid cells (UniProt P12838 localisation; HPA: tissue IHC profile). Use bone marrow hematopoietic cells as a positive tissue reference and review the no-primary control for detection-related colour (HPA: High in bone marrow hematopoietic cells; standard IHC practice). Treat staining limited to cut edges, necrosis or broadly nuclear compartments as suspect until it survives those checks (standard IHC practice; UniProt P12838 localisation). Interpret extracellular deposits cautiously because secreted DEFA4 can be found away from the cells producing it (UniProt P12838 secreted localisation; HPA: secreted-protein reliability note).
Boster reagents
Best DEFA4 / Defensin alpha 4 IHC Antibodies
Two human-reactive DEFA4 antibodies have IHC images from paraffin-embedded human tissue; both also list mouse and rat reactivity (catalog applications, reactivity and IHC captions). IF is listed for A06846 (catalog applications).
Real IHC data
Anti-Defensin alpha4 DEFA4 Antibody
Cat # A06846
Real IHC data
Anti-Defensin Alpha 4 (D27) DEFA4 Antibody
Cat # A06846-1
A06846 lists IHC, IF and ICC and shows IHC in paraffin-embedded human heart tissue (catalog applications; A06846 IHC caption). A06846-1 lists IHC and shows staining in paraffin-embedded human colorectal carcinoma tissue at 1:50 (catalog applications; A06846-1 IHC caption).
Which to pick: For tissue IHC, choose the SKU whose pictured specimen is more relevant: A06846 for paraffin-embedded human heart or A06846-1 for paraffin-embedded human colorectal carcinoma (respective IHC captions). For IF/ICC, choose A06846, a polyclonal antibody listing both applications; no IF figure is supplied (A06846 catalog applications and dilution data; catalog image listings). Both list human, mouse and rat reactivity, while their IHC captions document human paraffin sections only; the fixative is unreported (catalog reactivity; respective IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P12838 (DEF4_HUMAN, Defensin alpha 4).
- Human Protein Atlas. DEFA4 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. DEFA4 subcellular location (ICC-IF): Secreted.
- Human Protein Atlas. DEFA4 antibody validation summary (1 antibodies).
- Formalin-fixed paraffin-embedded renal biopsy tissues: an underexploited biospecimen resource for gene expression profiling in IgA nephropathy. Scientific reports 2020 — PMC7494931.
- PubMed PMID:8469233 — UniProt-cited evidence.
- PubMed PMID:16421571 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for DEFA4 (Defensin alpha 4). Expected localisation Cytoplasm in a subset of lymphoid cells (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A06846 at 1:100 - 1:300 (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 heart tissue; fixative not specified (datasheet A06846); 2. Fixation: Image fixative and duration unreported (datasheet A06846); 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-DEFA4, 1:100 - 1:300 (datasheet A06846); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Secreted protein: RNA and protein locations may differ (HPA tissue IHC); Isoform / epitope: No isoforms; processing may alter epitopes; no membrane side (UniProt); Regulation: Signal may vary with neutrophil abundance (UniProt). Evidence: UniProt P12838, HPA tissue IHC · Enhanced, HPA ICC-IF · Secreted, Datasheet A06846, PMC7494931. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/DEFA4/immunohistochemistry-ihc-guide.