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CX3CR1 / CX3C chemokine receptor 1 · IHC design guide
Design Immunohistochemistry for CX3CR1
Plan chromogenic CX3CR1 IHC in paraffin sections using the catalog antibody at 2–5 μg/ml (datasheet A00280-2). Compare the expected membrane location (UniProt) with reported cytoplasmic tissue staining (HPA tissue IHC), using tissue controls to assess the result.
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CX3CR1 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 | Membrane expected; cytoplasm seen in tissue IHC (UniProt) (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic signal in several tissues; caudate glia stain (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A00280-2) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific) | |
| Caveat | IHC staining has low consistency with RNA expression (HPA tissue IHC) | |
| Regulation | Inflammation recruits CX3CR1+ cells (UniProt) | |
| Isoform / epitope | 4 isoforms; extracellular vs cytoplasmic epitope coverage is unknown (UniProt) |
Section 1
Recommended CX3CR1 IHC & IF Protocols
The catalog antibody protocol uses heat-mediated EDTA retrieval (datasheet A00280-2). The four published IHC protocols below provide tissue-specific staining conditions (PMC3921448; PMC3399807; PMC5471565; PMC3730155).
| Sample | Paraffin-embedded human adenocarcinoma of the right colon tissue; fixative not specified (datasheet A00280-2) |
| Fixation | Image fixative and duration unreported (datasheet A00280-2); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A00280-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A00280-2) |
| Primary antibody | Rabbit anti-CX3CR1, 2-5 μg/ml (datasheet A00280-2) |
| Primary incubation | Overnight at 4 °C (datasheet A00280-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A00280-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CX3CR1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic expression in several tissues, including cerebral cortex. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 for the catalog antibody (datasheet A00280-2). For the published artery protocol, use its citrate pH 6.0 retrieval (PMC3399807).
Section 2
What Is the Expected CX3CR1 Staining Pattern?
CX3CR1 is a seven-pass cell-membrane receptor (UniProt P49238 topology). In paraffin-section IHC, assess staining in lymphocyte subsets and neural tissue, including microglia (UniProt P49238 tissue specificity and function). HPA reports medium glial-cell staining in caudate and cytoplasmic expression across several tissues, but rates its tissue IHC data Approved with low consistency between antibody staining and RNA expression (HPA tissue IHC).
| Cell outlines stain in an anatomically plausible population, with limited signal in adjacent cells. | Membrane-associated staining fits receptor topology (UniProt P49238 topology). Interpret the cell population alongside tissue context: HPA reports medium caudate glial-cell staining, while its tissue IHC profile also describes cytoplasmic staining (HPA tissue IHC). |
| Signal is confined to nuclei, with no convincing cell-outline staining. | An exclusively nuclear pattern conflicts with the reported cell-membrane location (UniProt P49238 subcellular location; HPA subcellular ICC-IF). Check the negative control and antibody dilution before scoring it as CX3CR1 (standard IHC practice). |
| Strong staining appears in a cell type listed as not detected, such as bronchial respiratory epithelium. | This conflicts with the sampled HPA tissue pattern, but one negative entry is not proof of universal absence (HPA tissue IHC). Consider cross-reactivity or endogenous detection activity; compare a negative control and tissue morphology (standard IHC practice). |
| Diffuse colour covers stroma and multiple cell types without clear cellular boundaries. | This is difficult to assign to a CX3CR1-positive population (UniProt P49238 tissue specificity; HPA tissue IHC). Background from detection or blocking is possible; inspect the negative control and reassess detection conditions (standard IHC practice). |
| No signal is visible in a section expected to contain HPA-positive cells. | HPA reports medium staining in caudate glial cells and several specified glandular-cell populations, not guaranteed positivity in every section (HPA tissue IHC). Confirm that the relevant cells are present, then review the IHC controls and assay conditions (standard IHC practice). |
💡Expected CX3CR1 appearanceA credible positive shows interpretable cell-associated staining in a plausible population, such as caudate glial cells with HPA-reported medium staining (HPA tissue IHC), with membrane localisation supported by receptor topology (UniProt P49238 topology); isolated nuclear signal or uniform colour across unrelated cells warrants scrutiny (standard IHC practice).
| Receptor topology | Seven transmembrane segments and extracellular and cytoplasmic regions support a membrane-localised interpretation (UniProt P49238 topology). Apparent intracellular colour in tissue IHC should be judged in context because HPA also describes cytoplasmic expression (HPA tissue IHC). |
| Tissue and cell context | HPA lists medium staining in caudate glia and cells of several glandular tissues, but not-detected staining in selected other cell types (HPA tissue IHC). Its Approved tissue profile has low staining–RNA consistency, so use these entries as comparison points rather than definitive identity tests (HPA tissue IHC). |
| Antibody validation | HPA lists HPA046587 and CAB032478 as Approved for IHC; HPA046587 is Supported for ICC (HPA antibodies). Those ratings do not make every stained cell CX3CR1-positive, particularly given the tissue-profile consistency caveat (HPA tissue IHC; standard IHC practice). |
| Isoforms | Four isoforms are listed (UniProt P49238 isoforms). This record supplies no isoform-specific tissue pattern or antibody epitope, so do not assign different staining patterns to particular isoforms (UniProt P49238 isoforms; HPA antibodies). |
| What should IF/ICC show? | HPA reports supported plasma-membrane localisation in ICC-IF and lists images from HEL, THP-1 and U2OS (HPA subcellular ICC-IF). Use that localisation as a comparison; IF/ICC assay design belongs in its own guide (HPA subcellular ICC-IF). |
| Situation | Likely cause | Next action |
|---|---|---|
| No colour in the chosen positive-control tissue | The sampled section may lack the relevant cells, or the IHC run may have failed (HPA tissue IHC; standard IHC practice). | Confirm the reported cell population is present; check a run control and review the validated IHC procedure, retrieval and antibody dilution before interpreting absence (standard IHC practice). |
| Uniform haze or stromal colour obscures cells | Background detection or incomplete blocking can obscure cellular staining (standard IHC practice). | Compare the negative control; optimise blocking, washes and detection conditions, then judge whether cell boundaries become discernible (standard IHC practice). |
| Only nuclei are strongly coloured | This disagrees with cell-membrane localisation (UniProt P49238 subcellular location; HPA subcellular ICC-IF). | Inspect the negative control and morphology; review antibody dilution and detection before assigning nuclear colour to CX3CR1 (standard IHC practice). |
| Unexpected epithelial cells stain strongly | Some glandular cells show medium HPA staining, while specified bronchial respiratory epithelial cells are not detected; tissue and cell identity matter (HPA tissue IHC). | Identify the exact cell population, compare its HPA tissue entry and check negative-control staining before concluding cross-reactivity (HPA tissue IHC; standard IHC practice). |
| Signal is mainly cytoplasmic rather than outlining cells | HPA tissue IHC describes cytoplasmic expression, whereas UniProt and HPA ICC-IF place CX3CR1 at the membrane (HPA tissue IHC; UniProt P49238 subcellular location; HPA subcellular ICC-IF). | Record the compartment and cell type separately; compare controls and treat compartment agreement across methods as supportive rather than required (standard IHC practice). |
| An HPA-listed negative cell type shows faint colour | Faint signal may reflect background; an HPA not-detected result describes its sampled tissue IHC observation (HPA tissue IHC; standard IHC practice). | Compare nearby cells and the negative control, then report intensity and distribution without treating faint colour alone as confirmed CX3CR1 (standard IHC practice). |
Experiment evidence
IHC & IF images showing CX3CR1 staining
A00280-2 · IHCIHC analysis of CX3CR1 using anti-CX3CR1 antibody (A00280-2). CX3CR1 was detected in a paraffin-embedded section of human adenocarcinoma of
A00280-2 · IHCIHC analysis of CX3CR1 using anti-CX3CR1 antibody (A00280-2). CX3CR1 was detected in a paraffin-embedded section of human liver cancer tissu
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000168329-CX3CR1/tissue/cerebral+cortex#imid_17237363
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000168329-CX3CR1/tissue/colon#imid_17237297
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000168329-CX3CR1/tissue/liver#imid_17237298
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000168329-CX3CR1/tissue/kidney#imid_17237291
HPA · ICC-IF HELHuman Protein Atlas immunofluorescence, HEL, antibody HPA046587; green = CX3CR1, blue = nucleus, red = microtubules.
HPA · ICC-IF HELHuman Protein Atlas immunofluorescence, HEL, antibody HPA046587; green = CX3CR1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CX3CR1 IHC & IF
🧪Run colon first and score its glandular cells for CX3CR1 staining (HPA: colon glandular cells, Medium). Use cervix glandular cells as the negative tissue (HPA: cervix glandular cells, Not detected); on the colon slide, use morphologically distinct cells without specific membrane staining as internal negatives, while checking their identity before interpreting them (HPA: colon glandular cells, Medium; UniProt P49238: cell membrane).
Positive control tissue: Adrenal gland (Glandular cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CX3CR1 in HEL, THP-1, U2OS, with annotated localisation: Plasma membrane (supported) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) control, a concentration-matched rabbit IgG isotype control matched to the primary antibody’s clonality, and CX3CR1-knockout tissue or cells as a biological negative (selected-SKU tissue-IHC caption: rabbit anti-CX3CR1 antibody). Quench endogenous peroxidase in colon sections before HRP/DAB detection, and assess endogenous biotin if an avidin–biotin system is used (selected-SKU tissue-IHC caption: colon section with peroxidase/DAB detection).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected-SKU paraffin-section caption does not state the fixative (selected-SKU tissue-IHC caption: fixative not stated). The caption uses heat-mediated retrieval in EDTA at pH 8.0, but does not establish whether retrieval is required for CX3CR1 staining (selected-SKU tissue-IHC caption: EDTA retrieval). Whether frozen sections or IF/ICC are easier is unreported; for IF/ICC, assess plasma-membrane localisation and tissue autofluorescence during interpretation (HPA subcellular: plasma membrane supported).
HPA tissue IHC evidence for CX3CR1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low consistency between antibody staining and RNA expression data.). 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 |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Breast | Glandular cells | Medium | Protein (IHC) | HPA → |
| Caudate | Glial cells | Medium | Protein (IHC) | HPA → |
| Colon | Glandular cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
| Cervix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Endometrium | Cells in endometrial stroma | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CX3CR1 IHC Tips
Troubleshoot CX3CR1 staining in paraffin sections by checking retrieval, compartment, cell identity and controls before assigning biological meaning.
What retrieval should I use when CX3CR1 staining is weak in paraffin sections?
Start with heat-mediated retrieval in EDTA at pH 8.0 for the catalog antibody (datasheet A00280-2). Its paraffin-section image used that retrieval before incubation with 2 μg/ml primary antibody overnight at 4°C (datasheet A00280-2). If staining is weak, first check that sections reached and stayed at the intended retrieval temperature, then compare a controlled change in heating time (standard IHC practice). Keep antibody concentration, detection and exposure to DAB consistent across that comparison (standard IHC practice). Score signal in cells and compartments separately, because stronger staining alone does not establish CX3CR1 specificity (UniProt P49238 localisation; standard IHC practice).
Could fixation explain weak or inconsistent CX3CR1 staining?
Target-specific fixation sensitivity is unknown: the selected paraffin-section caption does not report a fixative (datasheet A00280-2). Record the actual fixative and fixation duration for each specimen, and compare matched sections when investigating a loss of staining (standard IHC practice). Use the documented EDTA retrieval at pH 8.0 as a consistent starting condition while assessing those specimens (datasheet A00280-2). Include a known staining control and a negative control in the same run to separate specimen effects from detection failure (standard IHC practice). Do not assign a CX3CR1-specific fixation effect from tissue staining patterns or receptor topology alone (HPA tissue IHC; UniProt P49238 topology).
Should CX3CR1 appear at the membrane or in the cytoplasm?
CX3CR1 is a cell-membrane receptor with 7 transmembrane segments, so inspect convincing membrane-associated staining first (UniProt P49238 localisation and topology). The subcellular reference supports plasma-membrane localisation, while tissue IHC reports cytoplasmic staining in several tissues (HPA subcellular; HPA tissue IHC). Assess membrane and cytoplasmic signals separately rather than treating all brown staining as equivalent (standard IHC practice). Compare the pattern with expected immune or neural cells and with a negative control on the same run (UniProt P49238 tissue specificity; standard IHC practice). Diffuse cytoplasmic signal without corroborating cellular identity deserves additional validation, particularly given low IHC–RNA consistency (HPA tissue IHC).
Can the antibody distinguish CX3CR1 isoforms or an extracellular epitope?
The record lists 4 CX3CR1 isoforms, but the supplied antibody evidence does not map its epitope or establish isoform selectivity (UniProt P49238 isoforms; datasheet A00280-2). The receptor has extracellular loops, cytoplasmic loops and a cytoplasmic tail ending at residue 355 (UniProt P49238 topology). It also has a reported phosphothreonine at residue 346, without evidence here that this antibody recognizes a phosphorylation-dependent epitope (UniProt P49238 modified residues; datasheet A00280-2). Do not infer epitope orientation or isoform coverage from a positive chromogenic section alone (standard IHC practice). If either distinction matters, obtain epitope documentation and compare appropriate validated controls before interpreting differential staining (standard IHC practice).
How should I investigate CX3CR1 signal in multiplex IF?
Treat IF as a separate assay: the selected antibody evidence describes paraffin-section chromogenic IHC, with no IF condition established here (datasheet A00280-2). Pair CX3CR1 with a validated marker of the expected macrophage, microglial or lymphocyte population, chosen for the tissue being examined (UniProt P49238 tissue specificity; standard IF practice). Select fluorophores after examining unstained tissue autofluorescence, and include single-stain controls to assess channel bleed-through (standard IF practice). If the antibody epitope is extracellular, test staining without permeabilisation; if it is cytoplasmic, test controlled permeabilisation after checking epitope documentation (UniProt P49238 topology; standard IF practice). Interpret overlap at cell boundaries carefully because CX3CR1 has supported plasma-membrane localisation (HPA subcellular).
How can I reduce diffuse brown staining without losing CX3CR1 signal?
First inspect a no-primary control for endogenous enzyme activity and nonspecific detection signal (standard IHC practice). Apply a peroxidase block before HRP detection, and compare DAB development times across matched sections (standard IHC practice). The selected paraffin-section image used 10% goat serum blocking, 2 μg/ml primary antibody overnight at 4°C, and an HRP/DAB workflow (datasheet A00280-2). If background persists, titrate primary antibody around the documented concentration while holding retrieval and development constant (datasheet A00280-2; standard IHC practice). Evaluate whether residual colour follows tissue edges, folds or necrosis instead of identifiable cells before calling it CX3CR1 expression (standard IHC practice).
What is a defensible way to quantify CX3CR1 IHC across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and scoring compartment before measuring signal, because CX3CR1 is membrane-associated but tissue IHC has also reported cytoplasmic staining (UniProt P49238 localisation; HPA tissue IHC). For an intensity analysis, use a consistent 0–3 category scale and calculate an H-score from the percentage of cells in each category (standard IHC practice). Alternatively, report the percentage of positive cells or positive-cell density per mm² within a prespecified tissue region (standard IHC practice). Normalise counts to the eligible cell population or analysed tissue area, and exclude folds, edges and necrotic regions consistently (standard IHC practice). Keep retrieval, antibody concentration, DAB development and image thresholds matched across specimens (standard IHC practice).
When does CX3CR1 staining support a biological conclusion rather than artefact?
Seek staining in identifiable cells with a plausible membrane-associated pattern, consistent with CX3CR1's supported plasma-membrane localisation (HPA subcellular; UniProt P49238 localisation). Cell identity matters: the record describes expression in lymphocyte subsets and neural tissue, while the tissue IHC profile includes staining in several glandular populations (UniProt P49238 tissue specificity; HPA tissue IHC). Check whether signal tracks section edges, necrotic material or the no-primary control before interpreting it as receptor expression (standard IHC practice). Endogenous peroxidase can also produce misleading colour in an HRP/DAB assay, so inspect the blocked control (standard IHC practice). Treat unexpected compartments or cell types cautiously because the reported tissue staining has low consistency with RNA expression (HPA tissue IHC).
Boster reagents
Best CX3CR1 / CX3C chemokine receptor 1 IHC Antibodies
A00280-2 has real IHC data from human paraffin sections of right-colon adenocarcinoma, liver cancer, and lymphoma; no IF data are supplied (catalog image captions; catalog applications).
Real IHC data
Anti-CX3CR1 Antibody
Cat # A00280-2
A00280-2 is listed for human IHC, with a recommended concentration of 2–5 μg/ml (catalog applications and reactivity; datasheet: 2–5 μg/ml). Its IHC captions show staining in paraffin sections of human right-colon adenocarcinoma, liver cancer, and lymphoma (catalog image captions).
Which to pick: For human tissue IHC, choose polyclonal A00280-2: its paraffin-section caption reports EDTA retrieval at pH 8.0 and primary antibody at 2 μg/ml (catalog antibody description; A00280-2 IHC caption). The fixative is unreported, and A00280-2 has no listed IF/ICC application or IF image, so there is no supported IF/ICC choice here (A00280-2 IHC caption; catalog applications and images). For cross-species work, no SKU qualifies because A00280-2 lists human reactivity only (catalog reactivity).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P49238 (CX3C1_HUMAN, CX3C chemokine receptor 1).
- Human Protein Atlas. CX3CR1 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. CX3CR1 subcellular location (ICC-IF): Localized to the plasma membrane..
- Human Protein Atlas. CX3CR1 antibody validation summary (2 antibodies).
- CX3CL1 (fractalkine) and TNFα production by perfused human placental lobules under normoxic and hypoxic conditions in vitro: the importance of CX3CR1 signaling. Inflammation research : official journal of the European Histamine Research Society ... [et al.] 2014 — PMC3921448.
- Hydrogen sulfide inhibits the development of atherosclerosis with suppressing CX3CR1 and CX3CL1 expression. PloS one 2012 — PMC3399807.
- High Glucose Level Disturbs the Resveratrol-Evoked Curtailment of CX3CL1/CX3CR1 Signaling in Human Placental Circulation. Mediators of inflammation 2017 — PMC5471565.
- Fractalkine (CX3CL1) and its receptor CX3CR1 may contribute to increased angiogenesis in diabetic placenta. Mediators of inflammation 2013 — PMC3730155.
- PubMed PMID:7590284 — UniProt-cited evidence.
- PubMed PMID:7646814 — UniProt-cited evidence.
- PubMed PMID:12551893 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CX3CR1 (CX3C chemokine receptor 1). Expected localisation Membrane expected; cytoplasm seen in tissue IHC (UniProt) (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A00280-2). Validated IHC antibody: A00280-2 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human adenocarcinoma of the right colon tissue; fixative not specified (datasheet A00280-2); 2. Fixation: Image fixative and duration unreported (datasheet A00280-2); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: EDTA pH 8.0 (datasheet A00280-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A00280-2); 8. Primary antibody: Rabbit anti-CX3CR1, 2-5 μg/ml (datasheet A00280-2); 9. Primary incubation: Overnight at 4 °C (datasheet A00280-2). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: IHC staining has low consistency with RNA expression (HPA tissue IHC); Isoform / epitope: 4 isoforms; extracellular vs cytoplasmic epitope coverage is unknown (UniProt); Regulation: Inflammation recruits CX3CR1+ cells (UniProt). Evidence: UniProt P49238, HPA tissue IHC · Approved, HPA ICC-IF · plasma membrane., Datasheet A00280-2, PMC3921448, PMC3399807. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CX3CR1/immunohistochemistry-ihc-guide.