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CPAMD8 / C3 and PZP-like alpha-2-macroglobulin domain-containing protein 8 · IHC design guide
Design Immunohistochemistry for CPAMD8
Plan CPAMD8 paraffin-section IHC around cytoplasmic and membranous staining, including high signals in adipocytes and adrenal glandular cells (HPA tissue IHC). Start the catalog antibody at 0.5–1 μg/ml (datasheet A12898), and interpret results in light of uncertain agreement between staining and RNA expression (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CPAMD8 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 and membranous tissue staining (HPA tissue IHC) | |
| Staining pattern | Glandular and other cells: cytoplasmic/membranous staining (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet A12898) | |
| Positive control | Adipose tissue+4 more · see all | |
| Negative control | Appendix+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep paraffin-section fixation consistent (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A12898) | |
| Caveat | A secreted variant may make staining differ from tissue RNA (HPA tissue IHC) | |
| Regulation | Specific regulators are unreported (UniProt) | |
| Isoform / epitope | 2 isoforms; signal peptide is cleaved; verify epitope coverage (UniProt) |
Section 1
Recommended CPAMD8 IHC & IF Protocols
The catalog antibody protocol uses citrate pH 6 retrieval (datasheet A12898); the published cattle IHC protocol below uses TE pH 9 (PMC5500361).
| Sample | Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A12898) |
| Fixation | Image fixative and duration unreported (datasheet A12898); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Citrate pH 6, 20 min (datasheet A12898) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A12898) |
| Primary antibody | Rabbit anti-CPAMD8, 0.5-1μg/ml (datasheet A12898) |
| Primary incubation | Overnight at 4 °C (datasheet A12898) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A12898) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CPAMD8-positive staining in adipocytes of adipose tissue (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic and membranous expression in several different tissue types. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6 for the catalog antibody (datasheet A12898). The published TE pH 9 protocol used a different antibody (PMC5500361).
Section 2
What Is the Expected CPAMD8 Staining Pattern?
In paraffin IHC, expect cytoplasmic and membranous CPAMD8 staining in selected cell populations, including adipocytes, respiratory epithelium and cerebellar Purkinje cells (HPA: High; cytoplasmic and membranous profile). Secreted and cell-membrane annotations, with no transmembrane segment, make extracellular signal plausible but do not define its appearance (UniProt Q8IZJ3 topology). Interpret the pattern cautiously: HPA rates tissue IHC reliability Uncertain because staining and RNA expression have low consistency (HPA: tissue IHC reliability).
| Cytoplasmic and membranous staining in adipocytes, bronchial respiratory epithelial cells or cerebellar Purkinje cells. | This fits the reported compartment and cell types (HPA: cytoplasmic and membranous profile; High in each listed cell type). Compare staining within the named cells. HPA's Uncertain reliability means agreement supports a working interpretation, rather than confirming antibody specificity (HPA: tissue IHC reliability). |
| Predominantly nuclear staining, with little cytoplasmic or membranous signal in the expected cells. | A nuclear-dominant pattern differs from the reported tissue profile (HPA: cytoplasmic and membranous profile). Check the counterstain and detection controls, then reassess antibody specificity. The supplied record does not establish a nuclear CPAMD8 pattern (HPA: tissue IHC profile; UniProt Q8IZJ3 subcellular annotations). |
| Strong staining in appendix glandular cells or bone-marrow hematopoietic cells. | HPA reports CPAMD8 as Not detected in those specific cell populations (HPA: appendix glandular cells; bone-marrow hematopoietic cells). First consider nonspecific antibody binding or endogenous detection activity; do not treat either whole tissue as a universal negative control. |
| Widespread diffuse color obscures cell boundaries and appears in a no-primary control. | The control result points to detection background rather than interpretable CPAMD8 staining (general IHC practice). Distinguish diffuse background from plausible extracellular signal: CPAMD8 is annotated as secreted, while HPA's observed tissue profile is cytoplasmic and membranous (UniProt Q8IZJ3; HPA: tissue IHC profile). |
| No visible signal in adipocytes despite an intact section and readable counterstain. | Adipocytes are reported High by HPA, so their absence of staining warrants a technical and antibody check (HPA: adipocytes High). Confirm the cell identification and compare a second reported High population before concluding that the specimen lacks CPAMD8; HPA rates the IHC evidence Uncertain (HPA: tissue IHC reliability). |
💡Expected CPAMD8 appearanceCall a result provisionally positive when selected cells show discernible cytoplasmic and membranous signal, particularly in HPA-High adipocytes or bronchial respiratory epithelium; strong nuclear-only staining or color in no-primary controls is suspect (HPA: tissue profile and High cells; general IHC practice).
| Tissue and cell selection | HPA calls adipocytes, bronchial respiratory epithelial cells and cerebellar Purkinje cells High, while appendix glandular cells are Not detected (HPA: tissue IHC). Score the specified cell population, because these labels do not describe every cell in its tissue. |
| Compartment and processing | UniProt annotates CPAMD8 as secreted and cell-membrane associated, with a signal peptide at residues 1–25 and a chain at 26–1885 (UniProt Q8IZJ3). The record supplies no cleavage or shedding pattern to assign to a particular IHC signal. |
| Isoforms and epitope coverage | UniProt lists 2 isoforms, but the supplied evidence does not map an IHC antibody epitope to either one (UniProt Q8IZJ3; HPA: antibody list). A different staining result between antibodies cannot be attributed to an isoform without further epitope information. |
| Glycosylation | Five glycosylation sites are annotated at residues 117, 190, 267, 757 and 1439 (UniProt Q8IZJ3). These annotations alone do not predict antigen-retrieval requirements, fixation sensitivity or staining intensity in a paraffin section. |
| IHC antibody evidence | HPA rates IHC for HPA031327, HPA031328 and HPA031330 Uncertain (HPA: antibody validation). If comparing stains, record the antibody identity and judge agreement at the cell and compartment level; apparent agreement still needs cautious interpretation (HPA: tissue IHC reliability Uncertain). |
| IF/ICC question: should focal adhesions guide IHC scoring? | HPA reports focal adhesion sites in ICC-IF with uncertain localisation and lists HPA031329 as ICC Approved (HPA: subcellular summary; antibody validation). That observation does not establish a paraffin IHC pattern or an IHC protocol; use the tissue IHC profile for this application (HPA: tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| A reported High population gives no chromogenic signal. | Possible section, retrieval, antibody or detection failure (general IHC practice); HPA's High call alone does not identify the failed step (HPA: tissue IHC). | Check tissue preservation and the assay's positive and detection controls. Compare another HPA-High cell population, then optimize retrieval and antibody dilution within the IHC-validated antibody's instructions (general IHC practice; HPA: High populations). |
| Signal is predominantly nuclear. | The compartment differs from HPA's cytoplasmic and membranous tissue profile (HPA: tissue IHC); counterstain overlap or nonspecific signal may confuse localisation (general IHC practice). | Inspect the signal against the counterstain at higher magnification and review no-primary controls. Repeat with an independently assessed IHC antibody if available; HPA's listed IHC antibody ratings remain Uncertain (HPA: antibody validation). |
| Appendix glandular cells stain as strongly as a proposed positive control. | HPA reports those cells as Not detected; cross-reactivity or endogenous detection activity is possible (HPA: appendix glandular cells; general IHC practice). | Confirm that the stained cells are glandular cells, inspect a no-primary control and use the detection system's appropriate endogenous-activity block (general IHC practice). Reassess specificity against HPA-High cells (HPA: tissue IHC). |
| Brown signal spreads across most of the section or appears in the no-primary control. | Excess detection background or endogenous activity can obscure cell boundaries (general IHC practice). Secreted CPAMD8 makes extracellular localisation possible, but does not validate indiscriminate staining (UniProt Q8IZJ3). | Review blocking, washes and chromogen development using routine IHC controls (general IHC practice). Score CPAMD8 only where a reproducible cellular pattern remains distinguishable from control background (HPA: tissue IHC profile). |
| Two antibodies stain different cells or compartments. | HPA rates its three listed IHC antibodies Uncertain, and the tissue profile has low staining–RNA consistency (HPA: antibody validation; tissue IHC reliability). Epitope coverage is unspecified in the supplied record. | Record antibody IDs, section conditions and the exact cell populations. Compare matched sections and controls before choosing a working pattern; do not resolve the discrepancy by assuming an isoform or retrieval effect (UniProt Q8IZJ3: two isoforms; HPA: tissue IHC reliability). |
| ICC-IF shows focal adhesion signal that does not match paraffin IHC. | HPA's focal adhesion localisation is uncertain and comes from ICC-IF, while its tissue IHC profile is cytoplasmic and membranous (HPA: subcellular summary; tissue IHC). | Evaluate paraffin sections against the tissue IHC pattern and controls. Treat ICC-IF as a separate application with its own validation; HPA031329 is ICC Approved, while its supplied listing gives no IHC rating (HPA: antibody validation). |
Experiment evidence
IHC & IF images showing CPAMD8 staining
A12898 · IHCIHC analysis of CPAMD8 using anti-CPAMD8 antibody (A12898). CPAMD8 was detected in paraffin-embedded section of human lung cancer tissue. He
A12898 · IHCIHC analysis of CPAMD8 using anti-CPAMD8 antibody (A12898). CPAMD8 was detected in paraffin-embedded section of human lung cancer tissue. He
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000160111-CPAMD8/tissue/cerebral+cortex#imid_8348916
HPA · Thyroid glandHuman Protein Atlas IHC, Thyroid gland. Source: https://www.proteinatlas.org/ENSG00000160111-CPAMD8/tissue/thyroid+gland#imid_8341960
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000160111-CPAMD8/tissue/colon#imid_8351874
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000160111-CPAMD8/tissue/liver#imid_8351875
HPA · ICC-IF EFO-21Human Protein Atlas immunofluorescence, EFO-21, antibody HPA031329; green = CPAMD8, blue = nucleus, red = microtubules.
HPA · ICC-IF EFO-21Human Protein Atlas immunofluorescence, EFO-21, antibody HPA031329; green = CPAMD8, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CPAMD8 IHC & IF
🧪Run adipose tissue first and expect staining in adipocytes (HPA: High in adipocytes). Use appendix glandular cells as the negative tissue (HPA: Not detected in appendix glandular cells); on the adipose slide, adipocyte nuclei should remain at background as an internal negative compartment (UniProt Q8IZJ3: secreted; cell membrane).
Positive control tissue: Adipose tissue (Adipocytes, HPA High)
Negative control tissue: Appendix (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CPAMD8 in EFO-21, MCF-7, U2OS, with annotated localisation: Focal adhesion sites (uncertain) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; an isotype control matched to the primary antibody’s host and clonality, using rabbit IgG where appropriate (selected A12898 caption: rabbit primary; clonality unreported); and validated CPAMD8 knockout material or cognate peptide competition as a biological specificity control. Quench endogenous peroxidase and check endogenous biotin if using the caption’s biotin-based SABC/DAB detection (selected A12898 caption: biotinylated secondary, SABC and DAB).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A12898 paraffin-section caption does not state the fixative (selected A12898 caption: fixative unreported). The documented IHC approach used heat retrieval in citrate buffer at pH 6 for 20 minutes; whether retrieval is essential for CPAMD8 is unreported (selected A12898 caption). The supplied evidence does not establish that frozen sections or IF are easier; for adipose sections, check for tissue loss and empty spaces left by extracted lipid before scoring staining (HPA: High in adipocytes; standard histology practice).
HPA tissue IHC evidence for CPAMD8
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Low 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.). 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 |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | High | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Cerebellum | Purkinje cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Colon | Endothelial cells | Not detected | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Esophagus | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CPAMD8 IHC Tips
Troubleshoot CPAMD8 staining in paraffin sections by checking retrieval, controls, cellular pattern and detection before interpreting chromogenic signal.
What retrieval should I try when CPAMD8 staining is weak?
Start with heat-mediated retrieval in citrate buffer at pH 6 for 20 minutes (datasheet A12898). The selected paraffin-section example used this retrieval before an overnight incubation with 1 µg/mL catalog antibody at 4°C (datasheet A12898). If staining remains weak, compare a slightly shorter and longer heating interval on adjacent sections while holding antibody concentration, detection and development constant (standard IHC practice). Include a no-primary control and a consistently processed reference section, because stronger DAB after more heating can also reflect tissue damage or background rather than improved CPAMD8 detection (standard IHC practice).
How should I troubleshoot fixation-related loss of CPAMD8 staining?
The selected paraffin-section caption does not state a fixative, so CPAMD8-specific sensitivity to fixation is unknown (datasheet A12898). Record the actual fixative, fixation duration, specimen thickness and delay before fixation for each sample, then compare sections processed together under the same retrieval and staining conditions (standard IHC practice). If morphology is poor or staining varies across a section, check whether fixation and processing were uniform before increasing antibody or DAB exposure (standard IHC practice). Use a matched reference section and a no-primary control to distinguish a reproducible staining change from run-to-run variation, without treating either result alone as proof of antigen preservation (standard IHC practice).
Which CPAMD8 staining compartments are plausible in paraffin sections?
Assess membranous and cytoplasmic staining separately, because both appear in the tissue IHC profile, whose reliability is rated uncertain (HPA tissue IHC). CPAMD8 is annotated as secreted and associated with the cell membrane, with no transmembrane segment; a membrane-adjacent pattern therefore does not establish that the protein spans the membrane (UniProt Q8IZJ3). Focal adhesion localisation comes from an uncertain subcellular annotation and should remain a hypothesis when reading chromogenic tissue sections (HPA subcellular). Compare the pattern with tissue architecture and no-primary controls, and avoid calling diffuse extracellular DAB cell-specific expression without independent support (standard IHC practice; UniProt Q8IZJ3 topology).
Could isoforms or processing explain inconsistent CPAMD8 staining?
CPAMD8 has 2 annotated isoforms and a signal peptide at residues 1–25; its annotated mature chain spans residues 26–1885 (UniProt Q8IZJ3). Before comparing samples, check whether the catalog antibody's stated immunogen maps to a sequence shared by both isoforms; the supplied evidence does not give its epitope (UniProt Q8IZJ3 isoforms; datasheet A12898). CPAMD8 also has 5 annotated glycosylation sites, but their effect on this antibody's staining has not been established (UniProt Q8IZJ3 glycosylation; datasheet A12898). If staining differs by specimen, keep retrieval and detection matched and seek an independently validated epitope before assigning the difference to isoform expression (standard IHC practice).
How can I examine CPAMD8 with a cell-type marker by IF?
For a separate IF experiment, pair CPAMD8 with a marker for the expected cell population and verify each channel alone before interpreting overlap (standard IF practice). High staining in bronchial respiratory epithelial cells is one possible tissue-based starting point, although the tissue IHC profile has uncertain reliability (HPA: High in bronchus respiratory epithelial cells; HPA tissue IHC). Choose fluorophores whose emission is distinguishable from the specimen's autofluorescence, and include unstained and single-label controls (standard IF practice). Select permeabilisation according to the documented epitope location and whether intracellular access is needed; the supplied catalog caption does not specify that epitope or validate an IF protocol (standard IF practice; datasheet A12898).
What should I check when CPAMD8 DAB staining is widespread?
Run a no-primary section through the same biotinylated secondary, streptavidin–biotin complex and DAB steps used in the selected example to identify detection-related background (datasheet A12898; standard IHC practice). Apply a peroxidase block and assess endogenous biotin where relevant, because either can complicate enzyme-based or biotin-based chromogenic detection (standard IHC practice). The example used 10% goat serum blocking and 1 µg/mL primary antibody overnight at 4°C, providing documented starting conditions for that catalog antibody (datasheet A12898). If background persists, titrate the primary antibody and development time on matched sections while checking whether tissue edges, damaged areas or the no-primary section stain similarly (standard IHC practice).
How should I score CPAMD8 staining across specimens? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, then record either the percentage of positive cells with intensity for an H-score or positive area per mm² for a regional analysis (standard IHC practice). Normalise cell-based results to the number of eligible cells and area-based results to the analysed viable tissue area, using identical thresholds across matched sections (standard IHC practice). Report membranous and cytoplasmic results separately because both patterns occur in the uncertain tissue IHC profile (HPA tissue IHC). Exclude folds, necrosis and edge artefacts using preset criteria, and retain the no-primary result to document the background against which positivity was called (standard IHC practice).
When should I doubt an apparent CPAMD8-positive result?
Treat a reproducible membranous or cytoplasmic pattern in anatomically plausible cells as more credible than isolated edge staining, necrotic deposits or signal also present without primary antibody (HPA tissue IHC; standard IHC practice). For example, the HPA profile reports high staining in bronchial respiratory epithelial cells but no detection in appendix glandular cells; its overall tissue IHC reliability remains uncertain (HPA: High in bronchus respiratory epithelial cells; HPA: Not detected in appendix glandular cells; HPA tissue IHC). Diffuse extracellular signal needs careful interpretation because at least one CPAMD8 variant is secreted (HPA tissue IHC). Check peroxidase-related background and confirm surprising compartments or cell populations with an independent antibody or orthogonal assay before assigning biological meaning (standard IHC practice).
Boster reagents
Best CPAMD8 / C3 and PZP-like alpha-2-macroglobulin domain-containing protein 8 IHC Antibodies
A12898 has real IHC data from paraffin sections of human lung and mammary cancer tissues (catalog: IHC image captions). Monkey reactivity is listed; IF data are absent (catalog: reactivity; IF images).
Real IHC data
Anti-CPAMD8 Antibody ®
Cat # A12898
A12898 will render with its own IHC figure from a paraffin section of human lung cancer tissue (catalog: figure caption). Its other IHC caption documents human mammary cancer tissue; the catalog lists human and monkey reactivity, but provides no monkey IHC image (catalog: IHC image captions; reactivity).
Which to pick: Choose A12898 for chromogenic IHC on paraffin sections: its captions document citrate retrieval at pH 6 for 20 minutes, a 1 μg/ml rabbit primary, and DAB detection in human tissue (catalog: IHC image captions). No IF/ICC validated SKU is supplied here; A12898 has no listed IF application, dilution or image (catalog: applications; IF dilution; IF images). A12898 is the cross-species candidate because human and monkey reactivity are listed, although its IHC images show human tissue only; its clone and the tissue fixative are unreported (catalog: reactivity; IHC image captions; clone).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q8IZJ3 (CPMD8_HUMAN, C3 and PZP-like alpha-2-macroglobulin domain-containing protein 8).
- Human Protein Atlas. CPAMD8 tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. CPAMD8 subcellular location (ICC-IF): Localized to the focal adhesion sites..
- Human Protein Atlas. CPAMD8 antibody validation summary (4 antibodies).
- Morgagnian cataract resulting from a naturally occurring nonsense mutation elucidates a role of CPAMD8 in mammalian lens development. PloS one 2017 — PMC5500361.
- PubMed PMID:15177561 — UniProt-cited evidence.
- PubMed PMID:15057824 — UniProt-cited evidence.
- PubMed PMID:10574462 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CPAMD8 (C3 and PZP-like alpha-2-macroglobulin domain-containing protein 8). Expected localisation Cytoplasmic and membranous tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet A12898). Validated IHC antibody: A12898 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adipose tissue (Adipocytes); negative Appendix. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A12898); 2. Fixation: Image fixative and duration unreported (datasheet A12898); 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: Citrate pH 6 , 20 min (datasheet A12898); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A12898); 8. Primary antibody: Rabbit anti-CPAMD8, 0.5-1μg/ml (datasheet A12898); 9. Primary incubation: Overnight at 4 °C (datasheet A12898). Watch for: Fixation: Keep paraffin-section fixation consistent (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A12898); Caveat: A secreted variant may make staining differ from tissue RNA (HPA tissue IHC); Isoform / epitope: 2 isoforms; signal peptide is cleaved; verify epitope coverage (UniProt); Regulation: Specific regulators are unreported (UniProt). Evidence: UniProt Q8IZJ3, HPA tissue IHC · Uncertain, HPA ICC-IF · focal adhesion sites., Datasheet A12898, PMC5500361. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CPAMD8/immunohistochemistry-ihc-guide.