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C1QTNF1 / Complement C1q tumor necrosis factor-related protein 1 · IHC design guide
Design Immunohistochemistry for C1QTNF1
Plan C1QTNF1 staining in paraffin sections using high-staining colon glandular cells and kidney tubular cells as reference tissues (HPA tissue IHC). Interpret cytoplasmic staining with care because C1QTNF1 is secreted and tissue RNA and protein patterns may differ (HPA tissue IHC; UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
C1QTNF1 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) | |
| Staining pattern | Cytoplasmic signal in glandular and kidney tubular cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Colon+4 more · see all | |
| Negative control | Caudate+1 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep paraffin-section fixation consistent across samples (standard IHC practice; not target-specific) | |
| Caveat | Secretion can uncouple tissue RNA and protein patterns (HPA tissue IHC) | |
| Regulation | Expression regulation is not annotated (UniProt) | |
| Isoform / epitope | 2 isoforms; signal peptide cleaved; epitope coverage unknown (UniProt) |
Section 1
Recommended C1QTNF1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is paired with one published protocol using kidney clear cell carcinoma and paired normal tissues (PMC10387556 methods).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet A09550-1); 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-C1QTNF1, 10 μg/mL (datasheet A09550-1) |
| 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 | C1QTNF1-positive staining in glandular cells of colon (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in most tissues. No signal in the no-primary control. |
💡Decision noteTry citrate pH 6.0 HIER at 95–98 °C for 20 min first (page retrieval); the published method does not specify retrieval (PMC10387556 methods).
Section 2
What Is the Expected C1QTNF1 Staining Pattern?
C1QTNF1 is secreted, with a signal peptide and no transmembrane segment (UniProt Q9BXJ1 topology). In paraffin-section IHC, HPA reports predominantly cytoplasmic staining across tissues, including high staining in colonic glandular cells and kidney tubular cells (HPA tissue IHC). Treat this as a provisional pattern: HPA rates tissue staining Uncertain because a secreted variant can make RNA and protein locations differ, and external verification is pending (HPA tissue IHC).
| Cytoplasmic staining in colonic or duodenal glandular cells, or kidney tubular cells. | This matches HPA's high-staining cell populations and broad cytoplasmic IHC profile (HPA tissue IHC). Compare the relevant cells with adjacent tissue and controls; high is HPA's reported category, not a required numerical score (HPA tissue IHC). |
| Predominantly nuclear staining in a paraffin section, with little cytoplasmic staining. | This does not match HPA's broad cytoplasmic tissue-IHC profile (HPA tissue IHC). Check whether the signal tracks nuclei in the negative reagent control. Nuclear signal alone does not settle specificity: HPA also reports approved nucleoplasm localisation by ICC-IF (HPA subcellular). |
| Strong signal in a cell population outside the HPA high-staining groups, with weak signal in those groups. | Question antibody specificity or endogenous chromogen activity before assigning the unexpected cells as positive (general IHC practice). HPA's tissue pattern is Uncertain, so a mismatch is a reason to investigate, not proof of cross-reactivity (HPA tissue IHC). |
| Diffuse color over tissue and empty spaces, with little cell-associated contrast. | This is difficult to score as the reported cytoplasmic pattern (HPA tissue IHC). Assess reagent-only controls, blocking and washes for nonspecific chromogen deposition (general IHC practice). Extracellular signal alone is ambiguous because C1QTNF1 is secreted (UniProt Q9BXJ1 subcellular location). |
| No staining in colonic glandular cells or kidney tubular cells. | These are HPA high-staining examples, so absent signal calls for a run and antibody check (HPA tissue IHC). Their reported staining is Uncertain; a failed section cannot by itself establish that the target is absent (HPA tissue IHC). |
💡Expected C1QTNF1 appearanceCall a section provisionally positive when cytoplasmic staining is clear in HPA high-staining glandular or tubular cells; isolated nuclear color or uniform diffuse deposit needs control-based review (HPA tissue IHC; general IHC practice).
| Tissue and cell choice | Colon and duodenum glandular cells, and kidney tubular cells, are reported High; glial cells in caudate and hippocampus are Not detected (HPA tissue IHC). Use these as comparison populations, while keeping HPA's Uncertain reliability attached to the interpretation (HPA tissue IHC). |
| Secretion and processing | C1QTNF1 has a signal peptide at residues 1–25, a mature chain at 26–281, and no transmembrane segment (UniProt Q9BXJ1 topology and processing). A strictly membrane-bound interpretation is unsupported; extracellular color needs spatial and control review because the protein is secreted (UniProt Q9BXJ1 subcellular location; general IHC practice). |
| Antibody validation | The listed IHC antibody CAB025429 is rated Uncertain; HPA051101 is approved for ICC, with no IHC status listed (HPA antibodies). Do not transfer ICC approval to paraffin-section IHC or treat one antibody's staining as independently confirmed (HPA antibodies). |
| Isoforms and epitope coverage | Two isoforms are listed, and the mature chain contains collagen-like and C1q domains (UniProt Q9BXJ1 isoforms, processing and domains). Without an epitope map for the IHC reagent in these payloads, the recognised isoform or domain cannot be assigned; avoid explaining a negative section through presumed epitope loss. |
| IF/ICC Q&A | Q: Should IF look identical to tissue IHC? A: HPA reports approved nucleoplasm and cytosol localisation in ICC-IF, whereas tissue IHC is broadly cytoplasmic and rated Uncertain (HPA subcellular; HPA tissue IHC). Interpret each application against its own evidence; this section provides no IF protocol. |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected glandular or tubular cells show no chromogen signal. | The IHC run or reagent may have failed; HPA lists these cells as High but rates tissue staining Uncertain (HPA tissue IHC). | Review the run's positive control, detection reagents, retrieval record and antibody dilution before judging target absence (general IHC practice). |
| Most of the section is uniformly brown, including areas without clear cells. | Nonspecific deposition or detection background may obscure the reported cytoplasmic pattern (general IHC practice; HPA tissue IHC). | Compare a negative reagent control, inspect blocking and wash steps, and score only signal with interpretable tissue structure (general IHC practice). |
| Color follows nuclei but cytoplasm is faint in paraffin IHC. | The distribution differs from HPA's cytoplasmic tissue profile, although nucleoplasm is approved in ICC-IF (HPA tissue IHC; HPA subcellular). | Check negative controls and section morphology; describe the nuclear IHC pattern separately rather than using ICC-IF approval to validate it (general IHC practice; HPA subcellular). |
| Unexpected cell types stain more strongly than the HPA high-staining cells. | Cross-reactivity or endogenous detection activity is possible; HPA tissue staining remains Uncertain (general IHC practice; HPA tissue IHC). | Compare controls and the expected cell populations in the same run; avoid assigning target expression from the unexpected signal alone (general IHC practice; HPA tissue IHC). |
| Signal appears mainly between cells or along tissue edges. | Secretion makes extracellular location possible, while edge or diffuse deposit can reflect staining artefact (UniProt Q9BXJ1 subcellular location; general IHC practice). | Inspect negative controls, tissue integrity and whether signal is reproducible in intact regions before calling it specific (general IHC practice). |
| A low-staining tissue is used to declare the assay negative. | HPA reports Low staining in liver cholangiocytes and breast glandular cells, so weak signal there is less informative than a High example (HPA tissue IHC). | Include a reported High population, such as colonic glandular cells, when evaluating run sensitivity; retain the Uncertain HPA reliability caveat (HPA tissue IHC). |
Experiment evidence
IHC & IF images showing C1QTNF1 staining
A09550-1 · IHCImmunohistochemistry of CTRP1 in human kidney tissue with CTRP1 antibody at 10 μg/mL.
A09550-1 · IFImmunofluorescence of CTRP1 in Human Kidney cells with CTRP1 antibody at 20 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000173918-C1QTNF1/tissue/cerebral+cortex#imid_6961312
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000173918-C1QTNF1/tissue/colon#imid_6961230
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000173918-C1QTNF1/tissue/liver#imid_6961231
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000173918-C1QTNF1/tissue/kidney#imid_6961232
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA051101; green = C1QTNF1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA051101; green = C1QTNF1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for C1QTNF1 IHC & IF
🧪Run kidney first: tubular cells should stain (HPA: High in kidney tubular cells; selected A09550-1 tissue-IHC caption: kidney at 10 µg/mL). Use caudate glial cells as the negative tissue (HPA: Not detected in caudate glial cells); on the kidney slide, assess nontubular cells as candidate internal negatives only after confirming their target status, and expect confirmed negatives to show background-level chromogen.
Positive control tissue: Colon (Glandular cells, HPA High)
Negative control tissue: Caudate (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show C1QTNF1 in A-549, PC-3, U2OS, with annotated localisation: Nucleoplasm (approved), Cytosol (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; an irrelevant isotype control matched to the primary antibody’s host species and clonality; and C1QTNF1 knockout tissue or competition with the immunizing peptide, if available. In kidney sections, check for endogenous peroxidase activity and, if using a biotin-based detection system, endogenous biotin before interpreting chromogen.
⚠️Feasibility: A target-specific fixation window and retrieval dependence are unreported in the supplied evidence; optimize antigen retrieval empirically, and note that the selected A09550-1 kidney caption does not report a fixative (selected tissue-IHC caption). No evidence here establishes that frozen sections or IF are easier than paraffin-section IHC; IF localization requires independent interpretation because secretion is annotated by UniProt while nucleoplasm and cytosol are reported by HPA (UniProt Q9BXJ1: Secreted; HPA subcellular: nucleoplasm and cytosol). Kidney endogenous peroxidase, and endogenous biotin when biotin-based detection is used, can confound staining and should be checked with the controls.
HPA tissue IHC evidence for C1QTNF1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex. Pending external verification.). 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 |
|---|---|---|---|---|
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
| Esophagus | Squamous epithelial cells | High | Protein (IHC) | HPA → |
| Kidney | Cells in tubules | High | Protein (IHC) | HPA → |
| Lymph node | Germinal center cells | High | Protein (IHC) | HPA → |
Section 3
Advanced C1QTNF1 IHC Tips
Use compartment, cell type, and matched controls to troubleshoot C1QTNF1 staining in paraffin sections; interpret tissue patterns cautiously because its tissue IHC reliability is uncertain (HPA tissue IHC).
What retrieval should I try when C1QTNF1 staining is weak in paraffin sections?
Start with citrate buffer at pH 6.0 for heat-induced epitope retrieval at 95–98 °C for 20 min (page retrieval rule). Allow sections to cool consistently, then compare matched sections with and without retrieval so tissue loss or excessive background is distinguishable from improved staining (standard IHC practice). If staining remains weak, vary heating time on adjacent sections before trying another buffer, and keep fixation history and detection conditions matched (standard IHC practice). Assess tubular cells in kidney as one comparison site, while treating staining intensity as provisional because the tissue IHC profile is rated uncertain (HPA tissue IHC: kidney tubular cells High; reliability Uncertain).
How should I troubleshoot variable C1QTNF1 staining between fixed tissue blocks?
Target-specific sensitivity to fixative type or fixation duration is unknown from the supplied evidence; the catalog kidney image caption does not state its fixative (caption: A09550-1). Record fixative, time before fixation, fixation duration, processing schedule, and section age for each block before comparing chromogenic intensity (standard IHC practice). Run adjacent sections through the same citrate pH 6.0 retrieval at 95–98 °C for 20 min and the same detection run to isolate block-related variation (page retrieval rule; standard IHC practice). If morphology or antigen preservation differs, compare blocks with matched internal tissue structures and report the limitation rather than assigning a C1QTNF1-specific fixation effect (standard IHC practice).
Should C1QTNF1 appear inside cells or outside them in tissue IHC?
C1QTNF1 is annotated as secreted, with a signal peptide at residues 1–25 and no transmembrane segment (UniProt Q9BXJ1). Tissue IHC nevertheless reports cytoplasmic expression in most tissues, including High staining in kidney tubular cells, so intracellular signal is plausible (HPA tissue IHC). Extracellular staining may reflect secreted protein, but its source cannot be assigned from a chromogenic deposit alone; compare the deposit with nearby intact cells and matched controls (UniProt Q9BXJ1; standard IHC practice). Nucleoplasmic and cytosolic locations are also reported in cell imaging, so document each compartment separately and avoid equating a tissue stain with secretion rate (HPA subcellular).
How can epitope uncertainty affect C1QTNF1 staining and antibody comparisons?
C1QTNF1 has 2 annotated isoforms, but the supplied evidence does not identify the catalog antibody's epitope or establish isoform coverage (UniProt Q9BXJ1; supplied antibody evidence). The precursor carries a signal peptide at residues 1–25; the annotated mature chain spans 26–281, so epitope location matters when interpreting staining (UniProt Q9BXJ1). A collagen-like region spans 99–140, a C1q domain spans 141–281, and a glycosylation site is annotated at residue 93 (UniProt Q9BXJ1). Request or verify epitope mapping before claiming isoform selectivity, and compare antibodies on adjacent sections using the same retrieval and scoring conditions (standard IHC practice).
How should I adapt the tissue findings to multiplex C1QTNF1 immunofluorescence?
For multiplex IF, pair C1QTNF1 with a tubular epithelial marker when examining kidney, since tubular cells are reported High by tissue IHC (HPA tissue IHC: kidney). Select a fluorophore channel with low measured tissue autofluorescence, and include single-label and no-primary controls to assess bleed-through and background (standard IF practice). The antibody epitope is unspecified; use permeabilisation when testing intracellular access to the reported cytosolic or nucleoplasmic pools, and compare an unpermeabilised condition if extracellular staining is of interest (HPA subcellular; UniProt Q9BXJ1; standard IF practice). Do not assume the catalog tissue-IHC image establishes IF performance or a fixation method: its caption reports kidney staining at 10 µg/mL without stating fixative (caption: A09550-1).
What controls help distinguish diffuse C1QTNF1 signal from chromogenic background?
Begin with a no-primary control and inspect unstained tissue for pigment or endogenous color before attributing diffuse deposit to C1QTNF1 (standard IHC practice). In a peroxidase-based chromogenic workflow, apply a peroxidase block and check whether DAB signal persists without primary antibody; these are general detection controls (standard IHC practice). Compare intact tubular cells, reported High in kidney, with glial cells reported Not detected in caudate and hippocampus, while allowing for the HPA profile's Uncertain reliability (HPA tissue IHC). If background increases after citrate pH 6.0 retrieval at 95–98 °C for 20 min, review washing and blocking alongside a matched retrieval control (page retrieval rule; standard IHC practice).
How should I score C1QTNF1 IHC across tissue regions and runs? ⚠ ANSWER MARKED FOR VERIFICATION
Define regions and eligible cell types before scoring, then record the percentage of positive cells and staining intensity with one threshold across matched runs (standard IHC practice). An H-score can combine the percentages at intensity grades 0–3 into a 0–300 value; report compartment-specific scores rather than pooling cellular and extracellular deposits (standard IHC practice; UniProt Q9BXJ1). For extracellular signal, measure positive area or integrated optical density per mm² of viable tissue and normalise to the corresponding assessed area (standard IHC practice). Keep retrieval, exposure, counterstain, and image analysis settings consistent, and avoid treating differences as protein abundance alone given the Uncertain tissue IHC reliability (page retrieval rule; HPA tissue IHC).
When is an apparent C1QTNF1-positive focus convincing rather than artefactual?
A convincing focus should recur in comparable viable tissue and show a coherent cell or extracellular pattern, with no matching deposit in the no-primary control (standard IHC practice; UniProt Q9BXJ1). Kidney tubular cells and several epithelial populations are reported High, whereas caudate and hippocampal glial cells are reported Not detected; use those patterns as context, not absolute validation (HPA tissue IHC: reliability Uncertain). Examine section edges, folds, and necrotic areas for concentrated chromogen, and exclude endogenous peroxidase signal with an appropriate control (standard IHC practice). Because C1QTNF1 is secreted and has no transmembrane segment, a sharply membrane-restricted claim needs independent support, while cytoplasmic tissue staining remains consistent with the reported profile (UniProt Q9BXJ1; HPA tissue IHC).
Boster reagents
Best C1QTNF1 / Complement C1q tumor necrosis factor-related protein 1 IHC Antibodies
A09550-1 has IHC-P and IF applications (catalog: applications), with images from human kidney tissue and human kidney cells (catalog: image captions). Human, mouse and rat reactivity is listed (catalog: reactivity).
Real IHC data
Anti-CTRP1 C1QTNF1 Antibody
Cat # A09550-1
A09550-1 is shown in IHC on human kidney tissue at 10 μg/mL (catalog: IHC image caption). The same SKU is shown in IF on human kidney cells at 20 μg/mL (catalog: IF image caption).
Which to pick: Choose A09550-1 for paraffin-section IHC (catalog: IHC-P); its IHC image shows human kidney tissue at 10 μg/mL, but the fixative is unreported (catalog: IHC image caption). For IF/ICC planning, A09550-1 has IF evidence in human kidney cells at 20 μg/mL; ICC preparation details are unreported (catalog: IF image caption). A09550-1 lists human, mouse and rat reactivity (catalog: reactivity), while its IHC and IF images show human samples only (catalog: image captions); the antibody is rabbit hosted and its clonality is unreported (catalog: host and clone).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9BXJ1 (C1QT1_HUMAN, Complement C1q tumor necrosis factor-related protein 1).
- Human Protein Atlas. C1QTNF1 tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. C1QTNF1 subcellular location (ICC-IF): Localized to the nucleoplasm and cytosol..
- Human Protein Atlas. C1QTNF1 antibody validation summary (2 antibodies).
- Dynamic network biomarker C1QTNF1 regulates tumor formation at the tipping point of hepatocellular carcinoma. Biomolecules & biomedicine 2024 — PMC11293248.
- High C1QTNF1 expression mediated by potential ncRNAs is associated with poor prognosis and tumor immunity in kidney renal clear cell carcinoma. Frontiers in molecular biosciences 2023 — PMC10387556.
- PubMed PMID:12975309 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:16625196 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for C1QTNF1 (Complement C1q tumor necrosis factor-related protein 1). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A09550-1 at 10 μg/mL (the product's own IHC validation image is shown). Controls (HPA): positive Colon (Glandular cells); negative Caudate. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet A09550-1); 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-C1QTNF1, 10 μg/mL (datasheet A09550-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep paraffin-section fixation consistent across samples (standard IHC practice; not target-specific); Caveat: Secretion can uncouple tissue RNA and protein patterns (HPA tissue IHC); Isoform / epitope: 2 isoforms; signal peptide cleaved; epitope coverage unknown (UniProt); Regulation: Expression regulation is not annotated (UniProt). Evidence: UniProt Q9BXJ1, HPA tissue IHC · Uncertain, HPA ICC-IF · nucleoplasm and cytosol., Datasheet A09550-1, PMC10387556. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/C1QTNF1/immunohistochemistry-ihc-guide.