CPAMD8 / C3 and PZP-like alpha-2-macroglobulin domain-containing protein 8 · IHC design guide

Design Immunohistochemistry for CPAMD8

Plan chromogenic IHC for CPAMD8 in paraffin sections using the catalog antibody’s documented conditions. Compare cytoplasmic and membranous staining with suitable controls, bearing in mind that tissue IHC evidence has uncertain reliability (HPA tissue IHC).

Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use

Immunohistochemistry protocol sheet for CPAMD8 (IHC for CPAMD8): expected localisation Cytoplasmic and membranous tissue staining (HPA tissue IHC), antibody A12898, validated IHC image, and IHC protocol steps — Printable **CPAMD8** IHC protocol sheet — expected localisation Cytoplasmic and membranous tissue staining (HPA tissue IHC), antibody A12898, controls and protocol steps. Open the full CPAMD8 IHC guide →

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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 cells: cytoplasmic and 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 fixation consistent across sections (standard IHC practice; not target-specific). Selected-image fixative and duration unreported (datasheet A12898); verify before use.
	Caveat	Secreted protein may appear away from RNA-positive cells (HPA tissue IHC)
	Regulation	Regulation unreported (UniProt)
	Isoform / epitope	2 isoforms; epitope overlap is unreported (UniProt)

Section 1

Recommended CPAMD8 IHC & IF Protocols

The catalog antibody uses citrate pH 6 retrieval (datasheet A12898); the published bovine ciliary body IHC protocol uses TE pH 9 retrieval (PMC5500361).

Recommended immunohistochemistry (IHC-P) protocol parameters
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 heat retrieval for the catalog antibody (datasheet A12898). Use the published TE pH 9 method when reproducing that study (PMC5500361).

Section 2

What Is the Expected CPAMD8 Staining Pattern?

CPAMD8 is annotated as secreted and cell membrane associated, with no transmembrane segment (UniProt Q8IZJ3 topology). In paraffin section IHC, expect cytoplasmic and membranous staining in selected cells, including adipocytes, glandular cells, respiratory epithelial cells, Purkinje cells and cardiomyocytes (HPA: tissue IHC). Treat the pattern as provisional: HPA rates tissue staining Uncertain because antibody staining and RNA expression have low consistency (HPA: tissue IHC reliability).

What am I looking at on my slide?
Cytoplasmic and membranous staining in adipocytes, adrenal glandular cells or cardiomyocytes.	These are reported High staining examples (HPA: tissue IHC). Compare the signal with cell morphology and a negative control (standard IHC practice). The HPA reliability rating is Uncertain, so a matching pattern supports interpretation without establishing antibody specificity (HPA: tissue IHC reliability).
Strong nuclear staining dominates in cells expected to show cytoplasmic or membranous signal.	Dominant nuclear staining departs from the reported tissue pattern (HPA: tissue IHC). Check the negative control and review detection and counterstain before calling it CPAMD8 (standard IHC practice). UniProt lists secreted and cell membrane locations, with no transmembrane segment; it does not list a nuclear location (UniProt Q8IZJ3 topology).
Prominent staining in bone marrow hematopoietic cells or appendix glandular cells.	HPA reports CPAMD8 as Not detected in these cell populations (HPA: tissue IHC). If the negative control also stains, investigate endogenous detection activity; if it does not, consider antibody cross-reactivity (standard IHC practice). A single unexpected field needs replication and tissue review.
Diffuse chromogen obscures cell borders across both expected positive and negative areas.	The distribution cannot be scored reliably against HPA's cytoplasmic and membranous pattern (HPA: tissue IHC). Inspect the negative control and reagent background, then reassess antibody concentration, blocking and wash conditions (standard IHC practice). Diffuse staining alone does not establish extracellular CPAMD8.
No staining in a well-preserved adrenal gland or heart muscle section.	HPA reports High signal in adrenal glandular cells and cardiomyocytes (HPA: tissue IHC). Confirm tissue identity and control performance, then review retrieval, antibody dilution and detection steps (standard IHC practice). Because HPA tissue reliability is Uncertain, one absent signal is not definitive evidence of absent CPAMD8.

💡Expected CPAMD8 appearanceCall a section provisionally positive when identifiable HPA-listed cells show interpretable cytoplasmic and membranous chromogen, with High signal in the listed positive examples; dominant nuclear staining or widespread control-matched color warrants investigation (HPA: tissue IHC; standard IHC practice).

How each factor affects the staining
Secreted and cell membrane annotation	CPAMD8 has a signal peptide at residues 1–25 and no transmembrane segment (UniProt Q8IZJ3 topology). Its secreted annotation makes a strict membrane-only scoring rule unsuitable; evaluate any extracellular signal with morphology and controls rather than assuming its identity (standard IHC practice).
Tissue pattern and confidence	HPA describes cytoplasmic and membranous expression across several tissues, but rates tissue IHC Uncertain because staining and RNA data have low consistency (HPA: tissue IHC). Use the listed positive and undetected cell populations as comparisons, not absolute pass/fail standards.
Processing and isoforms	UniProt lists a mature chain at residues 26–1885 and 2 isoforms (UniProt Q8IZJ3 processing, isoforms). If an antibody's epitope is documented elsewhere, check whether it is retained in the form being assessed; this payload provides no antibody epitope location.
Antigen retrieval in paraffin IHC	Compare retrieval conditions against a positive tissue and matched controls when optimizing an assay (standard IHC practice). The supplied HPA and UniProt records report no CPAMD8-specific fixation sensitivity or retrieval requirement; do not attribute a changed signal to a documented CPAMD8 fixation effect.

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
Positive tissue has no interpretable chromogen.	Tissue identity, retrieval, dilution or detection may need review (standard IHC practice); HPA calls the tissue IHC pattern Uncertain.	Verify tissue and cell morphology, review a working assay control, and check retrieval and detection steps (standard IHC practice). Compare with an HPA High cell population, such as adrenal glandular cells (HPA: tissue IHC).
Negative control and test section both show broad color.	Shared signal suggests background from reagents or endogenous detection activity (standard IHC practice).	Review the negative control, endogenous-activity block, antibody concentration and washes; score CPAMD8 only after the shared background is resolved (standard IHC practice).
Nuclei stain more strongly than cell bodies or borders.	This conflicts with HPA's cytoplasmic and membranous tissue description (HPA: tissue IHC).	Review counterstain and detection controls, then repeat with an independently validated antibody if needed (standard IHC practice). HPA lists IHC validation as Uncertain for HPA031327, HPA031328 and HPA031330.
Unexpected cells stain while listed positive cells do not.	Possible cross-reactivity or assay background requires investigation (standard IHC practice); HPA tissue observations carry an Uncertain rating.	Compare cell morphology with HPA's cell-specific entries and inspect negative controls. Repeat the comparison before assigning the unexpected signal to CPAMD8 (HPA: tissue IHC; standard IHC practice).
A liver section appears inconsistent with the expected pattern.	UniProt reports lower liver tissue expression, while HPA reports cholangiocytes as Not detected; these describe different scopes (UniProt Q8IZJ3 tissue specificity; HPA: tissue IHC).	Identify the stained liver cell type before interpreting the result. Do not treat UniProt's tissue-level statement as a prediction that cholangiocytes must stain.
Q: Does focal adhesion signal in IF establish the expected IHC pattern?	HPA reports focal adhesion sites as an uncertain ICC-IF location, while its tissue IHC summary is cytoplasmic and membranous (HPA: subcellular; HPA: tissue IHC).	A: Interpret paraffin section IHC against the tissue IHC pattern and its Uncertain reliability rating. Assess ICC-IF localization in its separate guide; it does not establish an IHC protocol or compartment requirement (HPA: tissue IHC; HPA: subcellular).

Source: UniProt Q8IZJ3 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing CPAMD8 staining

IHC analysis of CPAMD8 using anti-CPAMD8 antibody (A12898). CPAMD8 was detected in paraffin-embedded section of human lung cancer tissue. Heat mediated antigen retrieval was performed in citrate buffer (pH6, epitope retrieval solution) for 20 mins. The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 1μg/ml rabbit anti-CPAMD8 Antibody (A12898) overnight at 4°C. Biotinylated goat anti-rabbit IgG was used as secondary antibody and incubated for 30 minutes at 37°C. The tissue section was developed using Strepavidin-Biotin-Complex (SABC)(Catalog # SA1022) with DAB as the chromogen.

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.

← 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 require 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, compare adipocytes with non-adipocyte areas that remain at background, without assuming all non-adipocyte cells lack CPAMD8 (HPA: High in adipocytes).

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 no-primary (secondary-only) and host- and clonality-matched isotype controls, plus CPAMD8 knockout tissue or cells as a biological specificity control (standard IHC practice). Quench endogenous peroxidase and check endogenous biotin background when using the caption’s biotin-based DAB detection in adipose tissue (A12898 tissue-IHC caption: biotinylated secondary, SABC and DAB; standard IHC practice).

⚠️Feasibility: The selected A12898 paraffin-section caption reports citrate retrieval at pH 6 for 20 minutes, but reports no fixative; a target-specific fixation window or fixation effect is unreported (A12898 tissue-IHC caption). That caption supports trying retrieved paraffin sections, while the supplied evidence does not establish that frozen sections or IF are easier; HPA reports an uncertain focal-adhesion ICC-IF location (A12898 tissue-IHC caption; HPA: focal adhesion sites, uncertain). In adipose sections, lipid vacuoles can complicate interpretation of staining at cell borders, so assess signal against intact cell morphology (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 using the catalog antibody’s tissue IHC conditions, with separate considerations for IF/ICC.

How should I adjust retrieval when CPAMD8 staining is weak in paraffin sections?

Start with heat-mediated citrate buffer at pH 6 for 20 minutes (datasheet A12898). Keep the tissue section, antibody concentration and detection method consistent while comparing retrieval runs, so that a change in staining can be assigned to retrieval conditions (general IHC practice). If staining remains weak, test a longer heating interval on replicate sections and inspect tissue integrity before adopting the change (general IHC practice). Include a section processed under the documented conditions as a reference, because the reported CPAMD8 result used 1 μg/mL primary antibody overnight at 4°C (datasheet A12898).

Can I assume CPAMD8 staining will tolerate a different fixation schedule?

Target-specific sensitivity of CPAMD8 to fixative choice or fixation duration is unknown from the supplied evidence (datasheet A12898: fixative unreported). The documented image shows staining in a paraffin-embedded human lung cancer section, but its caption gives no fixative or fixation time (datasheet A12898). Record those variables for each specimen and compare matched sections before attributing an intensity difference to CPAMD8 abundance (general IHC practice). Keep citrate retrieval at pH 6 for 20 minutes during that comparison, and use morphology plus a common reference section to identify processing differences (datasheet A12898; general IHC practice).

Which staining compartments are plausible for CPAMD8, and which need scrutiny?

Evaluate cytoplasmic, membranous and possible extracellular staining in the context of morphology: CPAMD8 is annotated as secreted and cell membrane associated, without a transmembrane segment (UniProt Q8IZJ3), while tissue IHC reports cytoplasmic and membranous expression (HPA tissue IHC). A focal adhesion assignment comes from subcellular IF data and is marked uncertain (HPA subcellular), so it should not determine tissue IHC scoring by itself. Compare cell-associated staining with adjacent extracellular signal on the same section and document them separately (general IHC practice). Treat isolated nuclear staining as a specificity concern requiring controls, given the supplied localisation annotations (UniProt Q8IZJ3; HPA tissue IHC).

How do CPAMD8 isoforms and processing affect epitope interpretation?

CPAMD8 has 2 annotated isoforms, and its 1–25 signal peptide precedes the annotated 26–1885 chain (UniProt Q8IZJ3). The supplied antibody caption does not specify an immunogen or epitope, so staining cannot be assigned to one isoform or to the signal peptide (datasheet A12898). If a known epitope sequence becomes available, map it against both isoforms before interpreting differences between specimens (general IHC practice; UniProt Q8IZJ3). CPAMD8 also has 5 annotated glycosylation sites; evaluate any suspected epitope masking experimentally rather than inferring its effect from that annotation alone (UniProt Q8IZJ3; general IHC practice).

How should I examine CPAMD8 localisation with multiplex IF/ICC?

For IF/ICC, pair CPAMD8 with a marker that identifies the expected cell population in the specimen, then inspect signal within that population rather than relying on tissue-wide overlap (general IF practice). Choose spectrally separated fluorophores and reserve a bright channel for CPAMD8 when tissue autofluorescence obscures dim signal; include unstained and single-label controls (general IF practice). Plan permeabilisation around the antibody’s epitope: an intracellular epitope needs access, whereas a surface-exposed epitope can be assessed before permeabilisation (general IF practice). The epitope side is unspecified here, and the focal adhesion assignment is uncertain, so compare those conditions directly (datasheet A12898; HPA subcellular).

What should I check when CPAMD8 DAB staining is diffuse?

Compare the stained section with a no-primary control to assess secondary-reagent binding and endogenous detection chemistry before interpreting diffuse DAB signal (general IHC practice). The documented workflow used 10% goat serum blocking, a biotinylated secondary antibody and an avidin-biotin detection complex with DAB (datasheet A12898). Include a peroxidase block and appropriate endogenous-biotin controls where indicated by the detection system and tissue (general IHC practice). Because CPAMD8 is annotated as secreted and cell membrane associated, extracellular signal is plausible, but a uniform haze or staining confined to damaged edges still warrants a background check (UniProt Q8IZJ3; general IHC practice).

How should I score CPAMD8 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and compartment before scoring, since tissue IHC describes cytoplasmic and membranous CPAMD8 staining (HPA tissue IHC). For cell-associated DAB signal, report an H-score or percentage of positive cells using the same intensity thresholds across slides; score extracellular signal separately if present (general IHC practice; UniProt Q8IZJ3: secreted). Normalise positive-cell counts to the number of eligible cells, or stained area to analysed tissue area in mm², while excluding folds and necrotic regions (general IHC practice). Keep retrieval, imaging and threshold settings consistent, and record the analysed region for every specimen (general IHC practice).

How can I distinguish convincing CPAMD8 staining from artefact?

Look for reproducible staining in intact cells with cytoplasmic or membranous patterns, while allowing a separately assessed extracellular component because CPAMD8 is also annotated as secreted (HPA tissue IHC; UniProt Q8IZJ3). Check whether stained cells match the specimen’s identified cell populations; reported examples include high staining in bronchial respiratory epithelial cells and no detected staining in appendix glandular cells (HPA tissue IHC). Discount signal concentrated at section edges or necrotic areas, and investigate DAB in the no-primary control as possible detection background (general IHC practice). Interpret apparent positives cautiously because tissue IHC reliability is rated uncertain owing to low consistency with RNA expression (HPA tissue IHC).

Boster reagents

Best CPAMD8 / C3 and PZP-like alpha-2-macroglobulin domain-containing protein 8 IHC Antibodies

The catalog antibody has IHC images from paraffin-embedded human lung and mammary cancer sections (catalog image captions). Human and monkey reactivity is listed; IF data are absent (catalog applications/reactivity; image captions).

Real IHC data

Anti-CPAMD8 Antibody ®

Cat # A12898

View product →

A12898 has IHC images from paraffin-embedded human lung and mammary cancer sections (A12898 image captions). Its listed applications are ELISA, IHC and WB, with human and monkey reactivity; the captions document human tissue only (A12898 catalog; image captions).

Which to pick: Choose A12898 for paraffin-section IHC: its images document citrate retrieval at pH 6 for 20 minutes and primary antibody at 1 μg/ml (A12898 image captions). No IF/ICC application or image is listed, so there is no catalog-supported IF/ICC choice (A12898 catalog). Monkey reactivity is listed, but the IHC images show human tissue only; the fixative is unreported (A12898 catalog; image captions).

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.