CD248 / Endosialin · IHC design guide

Design Immunohistochemistry for CD248

Plan CD248 IHC-P using the catalog antibody at 2.5 μg/mL in human colon sections (datasheet A04735). Compare the low cytoplasmic tissue staining (HPA tissue IHC) with the expected membrane location (UniProt).

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

Immunohistochemistry protocol sheet for CD248 (IHC for CD248): expected localisation Low cytoplasmic tissue staining (HPA tissue IHC); membrane expected (UniProt), antibody A04735, validated IHC image, and IHC protocol steps — Printable **CD248** IHC protocol sheet — expected localisation Low cytoplasmic tissue staining (HPA tissue IHC); membrane expected (UniProt), antibody A04735, controls and protocol steps. Open the full CD248 IHC guide →

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CD248 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	Low cytoplasmic tissue staining (HPA tissue IHC); membrane expected (UniProt)
	Staining pattern	Low cytoplasmic staining in several tissues (HPA tissue IHC)
	Antigen retrieval	Citrate pH 6 HIER, heat-mediated (datasheet A04735)
	Positive control ⓘ	Duodenum+4 more · see all
	Negative control ⓘ	Adipose tissue+4 more · see all

Important caveats

Reasons your staining may differ from the expected pattern.

	Fixation	Formaldehyde-fixed colon shown (selected-SKU IHC image A04735); keep fixation consistent (standard IHC practice; not target-specific)
	Caveat	Staining and RNA show medium consistency (HPA tissue IHC)
	Regulation	Seen in angiogenesis and wound healing (UniProt)
	Isoform / epitope	2 isoforms; map extracellular vs cytoplasmic epitope (UniProt)

Section 1

Recommended CD248 IHC & IF Protocols

The catalog antibody’s IHC-P protocol is followed by published CD248 staining methods for fibrotic lung, renal carcinoma, and murine ankle joints (PMC4832513; PMC8006336; PMC3672796).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Formaldehyde-fixed, paraffin-embedded Human Colon tissue (datasheet A04735)
Fixation	Image formalin-fixed; duration unreported (datasheet A04735); 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 (datasheet A04735); 20 min, 95–100 °C (standard)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% serum (datasheet A04735)
Primary antibody	Rabbit anti-CD248, 2.5 μg/mL (datasheet A04735)
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	CD248-positive staining in paneth cells of duodenum (HPA tissue IHC: High). HPA tissue profile: Low cytoplasmic expression in several tissues. No signal in the no-primary control.

💡Decision noteStart with citrate pH 6 heat retrieval for the catalog antibody (datasheet: A04735). The renal carcinoma protocol also uses citrate retrieval, but does not state its pH (PMC8006336).

Section 2

What Is the Expected CD248 Staining Pattern?

CD248 is a membrane protein with an extracellular region at residues 18–687 and a transmembrane segment at 688–708 (UniProt Q9HCU0 topology). Expect staining in pericytes and stromal fibroblasts (UniProt Q9HCU0 tissue specificity). HPA also reports high staining in intestinal Paneth cells, while describing overall tissue IHC as low cytoplasmic expression in several tissues with Enhanced reliability and medium staining–RNA consistency (HPA tissue IHC).

What am I looking at on my slide?
Distinct staining outlines perivascular or stromal cells, with little signal in nearby normal vessel endothelium.	This fits the membrane location and reported pericyte and stromal fibroblast expression (UniProt Q9HCU0 topology and tissue specificity; HPA subcellular). Assess the stained cell's position and morphology before assigning it to a vessel wall: UniProt also reports CD248 in tumor endothelial cells.
Paneth cells stain strongly in a duodenum or small intestine section.	This matches the High Paneth cell staining recorded in both tissues (HPA tissue IHC). It offers a tissue IHC comparison, though HPA's overall profile includes low cytoplasmic staining and its Enhanced rating has medium consistency with RNA expression (HPA tissue IHC).
A broad nuclear signal dominates, or stain fills unrelated tissue structures without a clear cellular pattern.	Predominant nuclear staining conflicts with the plasma membrane location (HPA subcellular; UniProt Q9HCU0 topology). Treat the pattern as suspect and compare controls; misplaced stain alone cannot identify whether antibody binding or chromogenic detection caused it (general IHC practice).
Adipocytes or other cells listed as undetected show strong staining across the section.	HPA lists adipocytes in adipose tissue and breast as Not detected (HPA tissue IHC). Strong staining in those specific cells warrants a cross-reactivity or endogenous detection check. Do not classify the entire tissue as negative: HPA's entries identify cell types, not every cell in a section.
No staining appears in Paneth cells in a technically valid intestinal section.	That differs from HPA's High Paneth cell result (HPA tissue IHC). Check that Paneth cells are present, then review the antibody's IHC validation and the staining run. A blank section alone cannot distinguish a failed assay from a sampled area lacking the expected cells (general IHC practice).

💡Expected CD248 appearanceCall a result positive when cell-associated staining is convincing at the plasma membrane in morphologically identified pericytes or stromal fibroblasts (HPA subcellular; UniProt Q9HCU0 tissue specificity), or strong in intestinal Paneth cells (HPA tissue IHC); diffuse section-wide color or predominant nuclear staining is suspect (general IHC practice; HPA subcellular).

How each factor affects the staining
Compartment and epitope location	CD248 has a large extracellular region, one transmembrane segment, and a short cytoplasmic tail (UniProt Q9HCU0 topology). Its reported plasma membrane location guides compartment scoring (HPA subcellular). An antibody's exact epitope is not supplied, so topology cannot establish its retrieval requirements.
Tissue and cell-type context	HPA reports High Paneth cell staining, Medium endometrial stromal cell and glomerular cell staining, and Not detected adipocytes (HPA tissue IHC). These are cell-specific observations; score identified cells within each section rather than using a tissue name as a whole-section positive or negative label.
Antibody evidence and interpretation limit	HPA051856 has Enhanced IHC validation (HPA antibodies). HPA describes the tissue IHC result as Enhanced but notes medium consistency between antibody staining and RNA expression, plus stained cells or structures that are not annotated (HPA tissue IHC). Review morphology and controls before assigning an unexpected cell identity.
Antigen retrieval	Target-specific fixation effects are not established by the supplied assay evidence. Verify with a matched IHC source before attributing a result to fixation.
IF/ICC Q&A: where should signal appear?	At the plasma membrane: HPA lists this location as approved and lists ICC-IF images for ASC52telo and BJ [Human fibroblast] (HPA subcellular). HPA051856 has Approved ICC validation (HPA antibodies). This location evidence does not supply an IF/ICC protocol or establish staining intensity for either cell line.

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
No stain in an expected positive section	The examined area may lack identifiable positive cells, or the IHC run may have failed (general IHC practice).	Confirm Paneth cells are present when using duodenum or small intestine, where HPA reports High staining (HPA tissue IHC). Review the IHC-validated antibody's instructions and run controls before changing the interpretation (general IHC practice).
Positive-looking stain in normal vessel endothelium	Cell assignment may be uncertain in a crowded vessel wall; UniProt reports CD248 in pericytes and stromal fibroblasts and says normal endothelial cells are absent or barely detectable (UniProt Q9HCU0 tissue specificity).	Inspect morphology and the position of stained cells around the vessel. If the signal is truly endothelial, compare a suitable negative control and assess nonspecific staining before accepting it as CD248 (general IHC practice).
Strong signal in adipocytes	This conflicts with HPA's Not detected adipocyte entries for adipose tissue and breast; nonspecific binding or detection background is possible (HPA tissue IHC; general IHC practice).	Check the no-primary control and blocking and wash steps (general IHC practice). Score adipocytes separately from stromal or vascular cells, since the HPA negative designation applies to adipocytes (HPA tissue IHC).
Color develops in the no-primary control	The signal can arise from the detection system or endogenous tissue activity rather than primary-antibody binding (general chromogenic IHC practice).	Check the detection-only control, reagent blocking, and washes. Where a peroxidase-based system is used, verify the endogenous peroxidase block (general chromogenic IHC practice). Reassess the CD248 pattern only after control color is resolved.
Diffuse haze obscures cell borders	Excess background can reflect insufficient blocking or washing, or excessive reagent concentration (general IHC practice). It prevents a reliable comparison with the plasma membrane location (HPA subcellular).	Review blocking, washes, primary-antibody concentration, and detection exposure using controls (general IHC practice). Re-score only when cell outlines and tissue structures can be distinguished.
Cytoplasmic staining appears without a clear membrane outline	HPA's tissue overview reports low cytoplasmic expression in several tissues, although its ICC-IF location is plasma membrane (HPA tissue IHC; HPA subcellular). Compartment alone therefore does not settle whether a faint IHC signal is genuine.	Record intensity, cell identity, and any membrane accentuation; compare a matched negative control and HPA's cell-specific tissue observations (general IHC practice; HPA tissue IHC). Avoid calling widespread cytoplasmic color a strong positive solely from the tissue name.

Source: UniProt Q9HCU0 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing CD248 staining

Immunohistochemistry Validation of TEM-1 in Human Colon Tissue Immunohistochemical analysis of paraffin-embedded Human Colon tissue using anti-TEM-1 antibody (A04735) at 2.5 μg/ml. Tissue was fixed with formaldehyde and blocked with 10% serum for 1 h at RT; antigen retrieval was by heat mediation with a citrate buffer (pH6). Samples were incubated with primary antibody overnight at 4˚C. A goat anti-rabbit IgG H&L (HRP) at 1/250 was used as secondary. Counter stained with Hematoxylin.

A04735 · IHCImmunohistochemistry Validation of TEM-1 in Human Colon Tissue Immunohistochemical analysis of paraffin-embedded Human Colon tissue using an

Immunofluorescence Validation of TEM-1 in Human Colon Tissue Immunofluorescent analysis of 4% paraformaldehyde-fixed Human Colon Tissue labeling TEM-1 with A04735 at 20 μg/mL, followed by goat anti-rabbit IgG secondary antibody at 1/500 dilution (red).

A04735 · IFImmunofluorescence Validation of TEM-1 in Human Colon Tissue Immunofluorescent analysis of 4% paraformaldehyde-fixed Human Colon Tissue labe

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000174807-CD248/tissue/cerebral+cortex#imid_14794056

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000174807-CD248/tissue/colon#imid_14781166

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000174807-CD248/tissue/liver#imid_14781167

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000174807-CD248/tissue/kidney#imid_14781160

HPA ICC-IF ASC52telo — CD248 (HPA051856)

HPA · ICC-IF ASC52teloHuman Protein Atlas immunofluorescence, ASC52telo, antibody HPA051856; green = CD248, blue = nucleus, red = microtubules.

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Real IHC / IF data behind the staining-pattern expectations in this section.

Sample controls for CD248 IHC & IF

🧪Run duodenum first and look for staining in Paneth cells (HPA: High in duodenum Paneth cells). Use bronchus respiratory epithelium as the tissue negative (HPA: Not detected); on the duodenum slide, compare Paneth cells with adjacent non-Paneth epithelium while assessing stromal staining separately (HPA: Paneth cells High; UniProt Q9HCU0: stromal fibroblast expression).

Positive control tissue: Duodenum (Paneth cells, HPA High)

Negative control tissue: Adipose tissue (HPA Not detected)

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CD248 in ASC52telo, BJ [Human fibroblast], with annotated localisation: Plasma membrane (approved) (HPA subcellular).

Technical controls: Include no-primary (secondary-only), a control immunoglobulin matched to the primary antibody’s host species, isotype and clonality, and a CD248-knockout section or validated immunizing-peptide block if available (standard IHC control practice). Quench endogenous peroxidase for chromogenic detection in duodenum and assess tissue autofluorescence if using fluorescence detection (standard IHC/IF practice).

⚠️Feasibility: A target-specific fixation window or fixation effect is unreported; the A04735 colon IHC caption text says formaldehyde fixation but gives no duration, while its fixative metadata says “not stated in the caption” (selected-SKU caption and metadata). That caption uses heat retrieval in citrate buffer at pH 6, so use it as a starting condition and check retrieval dependence on the chosen tissue (selected-SKU caption). The evidence does not establish that frozen sections or IF are easier; intestinal autofluorescence should be checked if duodenum is examined by IF (HPA: duodenum Paneth cells High; standard IF practice).

HPA tissue IHC evidence for CD248

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. Antibody staining in cells/structures not annotated, view images.). 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
Duodenum	Paneth cells	High	Protein (IHC)	HPA →
Small intestine	Paneth cells	High	Protein (IHC)	HPA →
Appendix	Germinal center cells	Medium	Protein (IHC)	HPA →
Colon	Goblet cells	Medium	Protein (IHC)	HPA →
Endometrium	Cells in endometrial stroma	Medium	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
Adipose tissue	Adipocytes	Not detected	Protein (IHC)	HPA →
Adrenal gland	Glandular cells	Not detected	Protein (IHC)	HPA →
Bone marrow	Hematopoietic cells	Not detected	Protein (IHC)	HPA →
Breast	Adipocytes	Not detected	Protein (IHC)	HPA →
Bronchus	Respiratory epithelial cells	Not detected	Protein (IHC)	HPA →

Section 3

Advanced CD248 IHC Tips

Troubleshoot CD248 staining in paraffin sections by checking retrieval, compartment, cell type and controls before scoring chromogenic signal.

What retrieval should I try first for weak CD248 staining?

Start with heat-mediated retrieval in citrate buffer at pH 6 (datasheet A04735). The selected paraffin-section example used this retrieval before overnight primary-antibody incubation at 4°C (caption A04735). If staining remains weak, compare a second retrieval condition on adjacent sections while holding antibody concentration and detection constant, because retrieval changes can also increase background (standard IHC practice). Judge the conditions against a positive-control section and tissue morphology, and keep the condition that yields reproducible, anatomically plausible staining without widespread signal in the no-primary control (standard IHC practice; UniProt Q9HCU0 tissue specificity).

Could fixation explain weak or uneven CD248 staining?

CD248-specific sensitivity to fixation duration or fixative type is unknown from the supplied evidence; assess fixation as a general paraffin-IHC variable (standard IHC practice). Compare sections with documented processing histories, and avoid interpreting a difference between batches as a biological change until retrieval and detection have been held constant (standard IHC practice). For a suspected processing problem, stain a positive-control section alongside the affected section using the same antibody incubation and chromogenic development (standard IHC practice). Preserve morphology and record fixation and processing details for each batch, since poor preservation or uneven processing can make cell-level localisation and scoring unreliable (standard IHC practice).

Where should convincing CD248 signal appear in a paraffin section?

Expect cell-boundary staining as a useful localisation check: CD248 has an extracellular region at residues 18–687, a transmembrane segment at 688–708, and a cytoplasmic tail at 709–757 (UniProt Q9HCU0 topology). Plasma-membrane localisation is also reported in cell imaging (HPA subcellular: plasma membrane approved). Examine stromal and perivascular cells in their anatomical context, since pericytes and stromal fibroblasts are reported CD248-expressing populations (UniProt Q9HCU0 tissue specificity). Diffuse cytoplasmic staining alone needs caution: the tissue atlas reports low cytoplasmic expression in several tissues and flags staining in unannotated structures, so compare controls and morphology before assigning those cells as positive (HPA tissue IHC).

How should epitope location affect interpretation of variable staining?

First check the antibody's documented immunogen or epitope before assigning a negative stain to loss of CD248, because the supplied product caption does not specify an epitope (caption A04735). CD248 has 2 listed isoforms, an extracellular region at residues 18–687, and a cytoplasmic region at 709–757 (UniProt Q9HCU0). Its extracellular region contains many annotated glycosylation sites, but their effect on this antibody's paraffin-section staining is unknown (UniProt Q9HCU0 glycosylation; caption A04735). If samples disagree, compare an independently mapped antibody or an orthogonal expression measure, then interpret the result in light of the verified epitope and the cell population scored (standard IHC practice).

How can I follow up an IHC result with multiplex IF?

Use the IF/ICC guide to establish staining conditions separately; the selected product evidence describes chromogenic staining of paraffin-embedded colon, while HPA reports CD248 plasma-membrane localisation in cell imaging (caption A04735; HPA subcellular). Multiplex CD248 with a validated marker for the suspected pericyte or stromal-fibroblast population, checking each channel alone before judging overlap (UniProt Q9HCU0 tissue specificity; standard IF practice). Choose fluorophores and filter sets after inspecting unstained tissue autofluorescence, and include single-stain controls to assess bleed-through (standard IF practice). Once the antibody's epitope is known, keep permeabilisation minimal for an extracellular epitope and assess permeabilisation for a cytoplasmic-tail epitope, since the regions lie on opposite sides of the membrane (UniProt Q9HCU0 topology; standard IF practice).

How do I reduce widespread brown staining without losing CD248 signal?

Compare the stained section with a no-primary control and check whether brown deposits follow tissue edges, damaged areas or the expected cells (standard IHC practice). Block endogenous peroxidase before HRP detection and optimise washing and chromogen development, because these general workflow steps can affect background (standard IHC practice). The selected example used 10% serum for 1 hour at room temperature, followed by a primary concentration of 2.5 µg/ml; treat those as starting conditions for the catalog antibody (caption A04735). If background persists, adjust one variable at a time and retain conditions that preserve anatomically coherent cell staining in the positive control (standard IHC practice).

What should I score when CD248 staining is patchy? ⚠ ANSWER MARKED FOR VERIFICATION

Define the compartment and cell population before scoring, because CD248 is membrane-associated and is reported in pericytes and stromal fibroblasts (UniProt Q9HCU0 topology and tissue specificity). Within matched regions, record the percentage of positive eligible cells and staining intensity, then calculate an H-score if intensity categories are reproducible (standard IHC practice). For spatial questions, report positive-cell density per mm² of viable tissue or a defined stromal area, with the denominator stated explicitly (standard IHC practice). Apply the same section thickness, imaging settings, region-selection rules and background threshold across specimens; exclude folds, necrosis and edges from the scored area (standard IHC practice).

How can I distinguish true CD248 staining from an artefact?

Prioritise reproducible cell-associated staining in an anatomically plausible stromal or perivascular population, consistent with reported expression in fibroblasts and pericytes (UniProt Q9HCU0 tissue specificity). Check the membrane pattern against CD248 topology, but do not call every cytoplasmic signal false because the tissue atlas describes low cytoplasmic staining and notes unannotated stained structures (UniProt Q9HCU0 topology; HPA tissue IHC). Staining concentrated at section edges, folds or necrotic tissue needs review against an adjacent section and a no-primary control (standard IHC practice). Exclude endogenous enzyme signal with the appropriate detection controls before treating unexpected cell populations or diffuse deposits as evidence of CD248 expression (standard IHC practice).

Boster reagents

Best CD248 / Endosialin IHC Antibodies

A04735 has real IHC and IF images from human colon tissue (A04735 IHC and IF image captions).

Real IHC data

Anti-TEM1 CD248 Antibody

Cat # A04735

View product →

A04735 was validated for IHC-P on paraffin-embedded human colon tissue at 2.5 μg/mL (A04735 IHC image caption). A04735 was also validated for IF on human colon tissue at 20 μg/mL (A04735 IF image caption).

Which to pick: Choose A04735 for human tissue IHC-P; its own image caption documents paraffin sections and formaldehyde fixation (A04735 IHC image caption; catalog: Human reactivity). For IF, A04735 has human colon tissue data, while ICC validation is unreported (A04735 IF image caption; catalog: applications). No cross-species IHC/IF choice is supported: A04735 lists Human reactivity, and its clone and clonality are unreported (catalog: reactivity and clone).

Each figure is that product's own IHC / IF validation image from its datasheet.

References

UniProt Consortium. UniProt entry Q9HCU0 (CD248_HUMAN, Endosialin).
Human Protein Atlas. CD248 tissue IHC expression (reliability: Enhanced).
Human Protein Atlas. CD248 subcellular location (ICC-IF): Localized to the plasma membrane..
Human Protein Atlas. CD248 antibody validation summary (1 antibodies).
Role of CD248 as a potential severity marker in idiopathic pulmonary fibrosis. BMC pulmonary medicine 2016 — PMC4832513.
Pan-cancer analysis identified CD248 as a potential target for multiple tumor types. Frontiers in pharmacology 2025 — PMC12018388.
The Diagnostic and Immunotherapeutic Value of CD248 in Renal Cell Carcinoma. Frontiers in oncology 2021 — PMC8006336.
Characterisation of fibroblast-like synoviocytes from a murine model of joint inflammation. Arthritis research & therapy 2013 — PMC3672796.
PubMed PMID:10947988 — UniProt-cited evidence.
PubMed PMID:11084048 — UniProt-cited evidence.
PubMed PMID:14702039 — UniProt-cited evidence.