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ZP2 / Zona pellucida sperm-binding protein 2 · IHC design guide
Design Immunohistochemistry for ZP2
Plan ZP2 staining in paraffin sections using ovarian follicle cells as an IHC reference (HPA tissue IHC). This guide covers fixation consistency, expected cytoplasmic staining and epitope choice after ZP2 processing (HPA tissue IHC; UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
ZP2 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); zona pellucida expected (UniProt) | |
| Staining pattern | Cytoplasmic staining in oocytes and placenta; cerebellar synapses (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet PB9912) | |
| Positive control | Ovary+4 more · see all | |
| Negative control | Adrenal gland+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | A secreted variant may separate protein staining from RNA sites (HPA tissue IHC) | |
| Regulation | Tissue dependent; brain-enriched RNA (HPA tissue RNA) | |
| Isoform / epitope | 2 isoforms; mature chain lacks tail, affecting epitope choice (UniProt) |
Section 1
Recommended ZP2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by published ZP2 staining protocols for colon and ovarian paraffin sections (PMC8067760; PMC11574796).
| Sample | Paraffin-embedded human intestinal cancer tissue; fixative not specified (datasheet PB9912) |
| Fixation | Image fixative and duration unreported (datasheet PB9912); 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 PB9912); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet PB9912) |
| Primary antibody | Rabbit anti-ZP2, 0.5-1μg/ml (datasheet PB9912) |
| Primary incubation | Overnight at 4 °C (datasheet PB9912) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9912) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | ZP2-positive staining in follicle cells of ovary (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression most abundant in oocytes and placenta as well as synapses in cerebellum. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 heat retrieval for the catalog antibody (datasheet PB9912); the ovarian study used 0.01 M citrate retrieval (PMC11574796).
Section 2
What Is the Expected ZP2 Staining Pattern?
ZP2 is a zona pellucida component with an extracellular region at residues 39–716 and a membrane segment at 717–736 (UniProt Q05996 topology). In ovary, assess the oocyte-associated zona pellucida while recording follicle-cell staining separately: HPA reports abundant oocyte cytoplasmic staining and High follicle-cell staining (HPA tissue IHC). HPA rates its tissue staining Enhanced, with medium staining–RNA consistency and retitration pending (HPA tissue IHC).
| A defined rim surrounds an oocyte; nearby follicle cells also stain. | The rim fits ZP2’s extracellular zona pellucida location (UniProt Q05996). Follicle-cell staining is separately reported as High (HPA tissue IHC); score the two compartments separately. |
| Oocyte cytoplasm stains, with little visible rim. | Oocyte cytoplasmic staining appears in the HPA profile (HPA tissue IHC), but the extracellular zona pellucida is ZP2’s established location (UniProt Q05996). Record both observations; cytoplasmic signal alone does not confirm matrix localisation. |
| Nuclei dominate the signal, or staining follows unrelated tissue structures. | A nuclear pattern conflicts with ZP2’s extracellular and membrane annotation (UniProt Q05996 topology). Check morphology, counterstain and control slides before attributing an unrelated structure’s signal to ZP2 (general IHC practice). |
| Many cell types stain uniformly, including a tissue listed as negative. | Broad staining is less persuasive when HPA reports Not detected glandular cells in adrenal gland, appendix or breast (HPA tissue IHC). Consider nonspecific antibody binding or endogenous chromogenic activity (general IHC practice). |
| No signal appears in ovarian material expected to contain oocytes. | HPA reports oocyte-associated staining and High follicle-cell staining (HPA tissue IHC). Confirm that the section contains an intact follicle, then review staining controls and antibody titration (general IHC practice). |
💡Expected ZP2 appearanceCall a result supportive when a discrete oocyte-associated zona pellucida rim is visible (UniProt Q05996), with follicle-cell staining assessed separately against HPA’s High report (HPA tissue IHC); diffuse staining across unrelated structures is a warning sign (general IHC practice).
| Extracellular topology and processing | ZP2 has a signal peptide at 1–38, an extracellular region at 39–716 and a propeptide at 641–745 (UniProt Q05996). The detected compartment may depend on where an antibody binds; its epitope is unspecified here. |
| Ovarian cell-type assignment | HPA describes abundant oocyte cytoplasmic staining but lists follicle cells as High in ovary (HPA tissue IHC). Keep these observations separate from the extracellular zona pellucida annotation (UniProt Q05996). |
| Evidence strength | HPA labels tissue IHC Enhanced, while noting medium staining–RNA consistency, possible differences between secreted protein and RNA locations, and pending retitration (HPA tissue IHC). Interpret unexpected compartments with those limits in mind. |
| Other reported tissues | HPA reports Medium staining in cerebellar synapses, cardiomyocytes, kidney tubules, keratinocytes, stomach glands and seminiferous-duct cells (HPA tissue IHC). These observations are useful comparisons, not evidence that every positive structure contains zona pellucida. |
| IF/ICC: what pattern is established? | HPA summarises ZP2 as membrane associated and secreted, but supplies no ICC-IF image-bearing cell lines or main-location assignment (HPA subcellular). This record cannot establish an IF/ICC cell-line pattern; assess that application in its own guide. |
| Situation | Likely cause | Next action |
|---|---|---|
| An ovarian section shows no oocyte-associated signal. | The section may lack an intact oocyte or follicle, or the IHC run may have failed (general IHC practice). HPA’s ovarian staining remains the comparison point (HPA tissue IHC). | Verify follicle morphology, then inspect the positive control and detection controls; titrate the IHC-validated antibody if needed (general IHC practice; HPA tissue IHC: retitration pending). |
| Only follicle cells are strongly positive. | High follicle-cell staining is reported by HPA, while ZP2’s zona pellucida location comes from UniProt (HPA tissue IHC; UniProt Q05996). | Document the follicle-cell result and check whether an oocyte and its rim are present; avoid calling the cell signal proof of matrix localisation (general IHC practice). |
| Signal is mainly nuclear. | Nuclear localisation is inconsistent with the supplied extracellular and membrane topology (UniProt Q05996). A misleading chromogen or counterstain appearance is possible (general IHC practice). | Review a counterstain-only or detection-control slide and compare signal with the tissue architecture before scoring ZP2 (general IHC practice). |
| Brown precipitate appears widely, including in a negative comparison tissue. | Nonspecific binding or endogenous chromogenic activity can produce broad staining (general IHC practice); HPA lists several tissue cell types as Not detected (HPA tissue IHC). | Inspect the no-primary control, check the detection-blocking step and compare the same structures across slides (general IHC practice). |
| Oocyte cytoplasm stains but no clear zona pellucida rim is resolved. | HPA reports oocyte cytoplasmic staining, whereas UniProt places ZP2 in the extracellular zona pellucida (HPA tissue IHC; UniProt Q05996). | Record cytoplasm and rim separately; inspect section morphology and a suitable positive control before assigning the signal to the matrix (general IHC practice). |
| A medium-positive tissue stains differently from ovary. | HPA reports Medium signals across several non-ovarian cell types and notes medium staining–RNA consistency (HPA tissue IHC). | Identify and score the cell type shown in that tissue, then review controls and staining intensity; do not expect an oocyte-like rim outside an ovarian follicle (HPA tissue IHC; UniProt Q05996; general IHC practice). |
Experiment evidence
IHC & IF images showing ZP2 staining
PB9912 · IHCIHC analysis of ZP2 using anti-ZP2 antibody (PB9912). ZP2 was detected in a paraffin-embedded section of human intestinal cancer tissue. Hea
PB9912 · IHCIHC analysis of ZP2 using anti-ZP2 antibody (PB9912). ZP2 was detected in frozen section of human placenta tissue . The tissue section was b
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000103310-ZP2/tissue/cerebral+cortex#imid_21001827
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000103310-ZP2/tissue/colon#imid_21002609
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000103310-ZP2/tissue/liver#imid_21002626
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000103310-ZP2/tissue/kidney#imid_21002619
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for ZP2 IHC & IF
🧪Run ovary first and score staining in follicle cells (High; HPA: Ovary, Follicle cells); also inspect the zona pellucida around oocytes (UniProt Q05996 localization). Use adrenal gland glandular cells as the negative tissue (HPA: Adrenal gland, Glandular cells, Not detected); on the ovary slide, adjacent areas outside the expected staining should lack specific chromogen deposit (internal negative control).
Positive control tissue: Ovary (Follicle cells, HPA High)
Negative control tissue: Adrenal gland (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for ZP2; derive a cell-line control from the positive tissue's cell type (Follicle cells) and confirm it by RNA or western blot first.
Technical controls: Include no-primary (secondary-only) and concentration-matched rabbit IgG controls matched to the primary antibody’s clonality (caption: rabbit anti-ZP2; standard IHC practice), plus a ZP2-knockout specimen if available as a biological negative (standard IHC practice). For ovary, check endogenous peroxidase and biotin background when using the caption’s SABC/DAB detection (caption: SABC/DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected PB9912 paraffin-section caption does not state a fixative (caption: fixative not stated). The reported IHC procedure uses heat retrieval in EDTA at pH 8.0; whether ZP2 staining depends on that retrieval condition is unreported (caption: EDTA retrieval). Paraffin-section IHC has a supplied example, while the payload provides no matched frozen-section or IF procedure to establish that either is easier; in ovary, distinguish staining around oocytes from follicle-cell staining when scoring (caption: paraffin section; HPA: Ovary, Follicle cells, High; UniProt Q05996 localization).
HPA tissue IHC evidence for ZP2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex. External characterization data supports antibody staining. Pending retitration.). 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 |
|---|---|---|---|---|
| Ovary | Follicle cells | High | Protein (IHC) | HPA → |
| Cerebellum | Synapses | Medium | Protein (IHC) | HPA → |
| Heart muscle | Cardiomyocytes | Medium | Protein (IHC) | HPA → |
| Kidney | Cells in tubules | Medium | Protein (IHC) | HPA → |
| Skin | Keratinocytes | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced ZP2 IHC Tips
Troubleshoot ZP2 staining by checking retrieval, compartment, controls, and scoring in paraffin sections before interpreting chromogenic signal.
What should I change when ZP2 staining is weak after antigen retrieval?
Start with heat-mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet PB9912). The selected image used that retrieval before overnight incubation at 4°C with 1 μg/ml primary antibody, so check those conditions and the detection reagents before changing retrieval (caption PB9912). Compare a positive control and a no-primary control processed alongside the test section; excessive heating can also damage morphology and complicate scoring (standard IHC practice). If signal remains weak, test a different retrieval condition on adjacent sections as a fallback, recording staining and morphology together rather than treating increased DAB intensity alone as improvement (standard IHC practice).
Could fixation explain weak or uneven ZP2 staining?
Target-specific sensitivity of ZP2 to fixation is unknown from the supplied evidence; the selected paraffin-section caption does not state its fixative (caption PB9912). Record the actual fixative, fixation duration, tissue thickness, and processing history for each specimen, then compare sections processed as similarly as possible (standard IHC practice). Assess preserved morphology and staining in a concurrently processed positive control before changing primary-antibody concentration or retrieval, because variable processing can confound that comparison (standard IHC practice). Do not infer a ZP2-specific fixation effect from its extracellular domain, glycosylation sites, or reported tissue staining; those observations address different properties (UniProt Q05996 topology and glycosylation; HPA tissue IHC).
Where should convincing ZP2 staining appear in a tissue section?
Prioritise staining associated with the oocyte’s surrounding zona pellucida, consistent with ZP2’s extracellular-matrix location and its reported expression in oocytes (UniProt Q05996 localisation and tissue specificity). The precursor has an extracellular region at residues 39–716 and a transmembrane segment at 717–736, so an antibody’s epitope and processing state matter when interpreting a membrane-adjacent pattern (UniProt Q05996 topology and processing). HPA also reports high staining in ovarian follicle cells and cytoplasmic expression in oocytes and placenta, with medium consistency between staining and RNA (HPA tissue IHC). Record the stained compartment and cell type separately, and seek an independent control before assigning diffuse cytoplasmic signal to ZP2 (standard IHC practice; HPA tissue IHC).
How can epitope placement alter interpretation of ZP2 IHC?
Check the antibody’s documented immunogen or epitope before interpreting a negative section; the supplied caption does not specify either for PB9912 (caption PB9912). ZP2 has 2 listed isoforms, a signal peptide at 1–38, a propeptide at 641–745, and a listed chain at 39–640 (UniProt Q05996 isoforms and processing). Its extracellular region contains three annotated glycosylation sites at 105, 122, and 462, which makes epitope accessibility a question to test rather than assume (UniProt Q05996 topology and glycosylation). Compare staining with an independently validated antibody against a documented, distinct region when available, and avoid assigning isoform specificity without epitope evidence (standard IHC practice; UniProt Q05996 isoforms).
How should I investigate discordant ZP2 IHC and IF patterns?
Treat IF as a separate assay when comparing it with chromogenic IHC: the selected PB9912 evidence describes paraffin-section DAB detection, with no fixative reported (caption PB9912). Multiplex ZP2 with an independently validated marker of the expected oocyte population, and inspect whether the signals occupy compatible structures rather than assuming exact overlap (UniProt Q05996 tissue specificity and localisation; standard IF practice). Choose fluorophores whose emission is distinguishable from the specimen’s autofluorescence, and include single-stain and no-primary controls to assess bleed-through and background (standard IF practice). If the antibody epitope is extracellular, minimise permeabilisation; if it is intracellular, optimise permeabilisation separately, because epitope placement for PB9912 is not supplied (UniProt Q05996 topology; caption PB9912; standard IF practice).
How can I separate ZP2 signal from chromogenic background?
Run a no-primary section through the same secondary, detection, and DAB steps to identify signal unrelated to primary-antibody binding (standard IHC practice). The selected PB9912 image used a biotinylated secondary and streptavidin–biotin detection, so evaluate background from that detection system with matched controls (caption PB9912; standard IHC practice). Apply a peroxidase block and check for endogenous biotin where relevant; treat both as general chromogenic-workflow controls, not evidence of ZP2 expression (standard IHC practice). Compare signal after consistent washing and DAB development, and reject deposits concentrated at section edges, folds, or damaged areas when they persist without primary antibody (standard IHC practice).
What is a defensible way to quantify ZP2 IHC? ⚠ ANSWER MARKED FOR VERIFICATION
Define the compartment and region of interest before scoring, because ZP2 is associated with the zona pellucida while HPA reports staining in several cell populations (UniProt Q05996 localisation; HPA tissue IHC). For cellular staining, report the percentage of positive cells and an H-score using intensity categories 0–3; for matrix-associated staining, measure stained area or optical density per mm² of evaluable matrix (standard IHC practice). Normalise cellular counts to the relevant cell population and matrix measurements to intact matrix area, excluding folds, necrosis, and missing tissue by preset rules (standard IHC practice). Keep retrieval, detection, imaging, and score thresholds consistent across samples, and report control staining alongside the measurements (standard IHC practice).
When should an apparent ZP2-positive section be questioned?
Question a signal that appears only at section edges, folds, or necrotic areas, or that remains in the no-primary control after chromogenic development (standard IHC practice). Strong, isolated staining in an unexpected cell or compartment needs independent confirmation: ZP2 is annotated in the zona pellucida and oocytes, while HPA also reports broader staining with medium RNA–protein consistency (UniProt Q05996 localisation and tissue specificity; HPA tissue IHC). Check endogenous peroxidase and, for biotin-based detection, endogenous biotin before calling such staining positive (caption PB9912; standard IHC practice). Document location and control results with the score, and distinguish an observed DAB pattern from a verified ZP2 assignment (standard IHC practice).
Boster reagents
Best ZP2 / Zona pellucida sperm-binding protein 2 IHC Antibodies
PB9912 has real IHC images from human paraffin-embedded intestinal cancer and frozen placenta sections (PB9912 IHC captions). No IF/ICC data are supplied (catalog payload).
Real IHC data
Anti-ZP2 Antibody ®
Cat # PB9912
PB9912 is listed for human IHC and is shown on a paraffin-embedded intestinal cancer section (catalog applications/reactivity; PB9912 IHC caption). Its second IHC image shows a frozen human placenta section (PB9912 IHC caption).
Which to pick: Choose PB9912 for human tissue IHC; its paraffin-section caption reports EDTA pH 8 retrieval and 1 μg/ml primary antibody (PB9912 IHC caption). No listed SKU has IF/ICC or non-human reactivity, and PB9912 is a rabbit antibody with clonality unreported (catalog applications/reactivity; catalog payload). The paraffin-section fixative is unreported, so fixation and tissue processing cannot be inferred (PB9912 IHC caption). The selected PB9912 tissue-IHC caption documents paraffin sections, but does not specify the fixative (selected-SKU IHC image PB9912).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q05996 (ZP2_HUMAN, Zona pellucida sperm-binding protein 2).
- Human Protein Atlas. ZP2 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. ZP2 subcellular location (ICC-IF): Membrane, Secreted.
- Human Protein Atlas. ZP2 antibody validation summary (1 antibodies).
- Dietary Soybean (Glycine max (L.) Merr.) Improved the ZP2 Expression in Female Swiss Mice. JBRA assisted reproduction 2023 — PMC10279445.
- Zona Pellucida Protein 2 (ZP2) Is Expressed in Colon Cancer and Promotes Cell Proliferation. Cancers 2021 — PMC8067760.
- Effects of hyperhomocysteinemia on follicular development and oocytes quality. iScience 2024 — PMC11574796.
- Glycan-Independent Gamete Recognition Triggers Egg Zinc Sparks and ZP2 Cleavage to Prevent Polyspermy. Developmental cell 2018 — PMC6549238.
- PubMed PMID:8385033 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15616553 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for ZP2 (Zona pellucida sperm-binding protein 2). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC); zona pellucida expected (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet PB9912). Validated IHC antibody: PB9912 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Ovary (Follicle cells); negative Adrenal gland. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human intestinal cancer tissue; fixative not specified (datasheet PB9912); 2. Fixation: Image fixative and duration unreported (datasheet PB9912); 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 PB9912); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet PB9912); 8. Primary antibody: Rabbit anti-ZP2, 0.5-1μg/ml (datasheet PB9912); 9. Primary incubation: Overnight at 4 °C (datasheet PB9912). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: A secreted variant may separate protein staining from RNA sites (HPA tissue IHC); Isoform / epitope: 2 isoforms; mature chain lacks tail, affecting epitope choice (UniProt); Regulation: Tissue dependent; brain-enriched RNA (HPA tissue RNA). Evidence: UniProt Q05996, HPA tissue IHC · Enhanced, HPA ICC-IF · Membrane, Secreted, Datasheet PB9912, PMC8067760, PMC11574796. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/ZP2/immunohistochemistry-ihc-guide.