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FCGR3A / Low affinity immunoglobulin gamma Fc region receptor III-A · IHC design guide
Design Immunohistochemistry for FCGR3A
Plan FCGR3A chromogenic IHC in paraffin sections with the IHC-validated antibody at 2–5 μg/mL (datasheet A01408-1). Assess the cytoplasmic staining reported in lung macrophages, liver Kupffer cells and lymph node cells, while considering the soluble receptor (HPA tissue IHC; UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
FCGR3A 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 in tissue (HPA tissue IHC); cell membrane (UniProt) | |
| Staining pattern | Cytoplasmic in lung macrophages, Kupffer and nodal cells (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A01408-1) | |
| Positive control | Lung+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 section fixation consistent (standard IHC practice; not target-specific) | |
| Caveat | Soluble receptor may complicate cell assignment (UniProt) | |
| Regulation | Regulation not specified in the record (UniProt) | |
| Isoform / epitope | No isoforms annotated; epitope side affects accessibility (UniProt) |
Section 1
Recommended FCGR3A IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet A01408-1) is accompanied by three published breast cancer IHC protocols (PMC2987696; PMC2976659; PMC2935495).
| Sample | Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet A01408-1) |
| Fixation | Image fixative and duration unreported (datasheet A01408-1); 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 A01408-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A01408-1) |
| Primary antibody | Rabbit anti-FCGR3A, 2-5μg/ml (datasheet A01408-1) |
| Primary incubation | Overnight at 4 °C (datasheet A01408-1) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A01408-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | FCGR3A-positive staining in macrophages of lung (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in a subset of cells including lung macrophages, Kupffer cells in liver and non-germinal center cells in lymph node. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 (datasheet A01408-1); the three article excerpts do not specify retrieval conditions (PMC2987696; PMC2976659; PMC2935495).
Section 2
What Is the Expected FCGR3A Staining Pattern?
FCGR3A is a cell-membrane receptor with an extracellular region at residues 17–208 and a transmembrane segment at 209–229; a soluble form also exists (UniProt P08637 topology and subcellular location). In paraffin-section IHC, expect staining in subsets of cells, especially lung macrophages, placental Hofbauer cells and splenic red-pulp cells (HPA: High in each). HPA describes the tissue pattern as cytoplasmic and rates its reliability Supported (HPA: tissue IHC).
| Distinct staining marks a subset of lung macrophages; adjacent respiratory epithelial cells remain unstained. | This distribution fits the observed tissue pattern: lung macrophages are High, while bronchial respiratory epithelial cells are Not detected (HPA: tissue IHC). Record which cells stain rather than assigning one intensity to the entire section (general IHC practice). |
| Positive cells show a cytoplasmic appearance, with or without a discernible cell-edge signal. | HPA describes cytoplasmic staining in selected tissue cells, while UniProt places the intact receptor at the cell membrane and reports a soluble form (HPA: tissue IHC; UniProt P08637 subcellular location). A membrane-only scoring rule would miss the reported IHC appearance. |
| Signal is predominantly nuclear or uniformly fills cells outside the expected positive subsets. | Treat this as a compartment or distribution mismatch requiring a specificity check; nuclear localisation is not reported for FCGR3A here (UniProt P08637 subcellular location; HPA: tissue IHC). Compare a no-primary control and the expected positive-cell pattern (general IHC practice). |
| Strong staining appears in bronchial respiratory epithelium or adipocytes. | Those cell types are Not detected in the supplied HPA tissue observations (HPA: bronchus respiratory epithelial cells; adipose adipocytes). Cross-reactivity or endogenous chromogenic activity are possibilities, not diagnoses; inspect controls before interpreting the signal (general IHC practice). |
| A known-positive section has no convincing positive cells. | Absence in lung macrophages, placental Hofbauer cells or splenic red-pulp cells conflicts with their High HPA observations (HPA: tissue IHC). Check cell identification and the staining run before calling the specimen negative (general IHC practice). |
💡Expected FCGR3A appearanceCall a section positive when identifiable expected cell subsets stain—often strongly in lung macrophages, Hofbauer cells or splenic red-pulp cells—with the cytoplasmic appearance reported by HPA; broad epithelial or nuclear staining warrants review (HPA: tissue IHC; UniProt P08637 subcellular location).
| Cell selection and comparator tissue | HPA rates lung macrophages, Hofbauer cells and splenic red-pulp cells High, but lymph-node non-germinal-center cells Low (HPA: tissue IHC). Compare like cell types when judging signal. |
| Membrane topology and soluble receptor | The extracellular domain spans residues 17–208, and a soluble receptor also exists (UniProt P08637 topology and subcellular location). Membrane topology alone does not define the appearance of a paraffin-section stain; use HPA's observed cytoplasmic pattern as the IHC reference (HPA: tissue IHC). |
| Antibody evidence | HPA lists IHC as Supported for HPA055431 and CAB032435; ICC status is unlisted for both (HPA: antibody validation). Supported tissue IHC does not establish an IF staining pattern. |
| IF/ICC Q: What should a positive cell look like? | A: Membrane-associated signal is biologically plausible for intact FCGR3A (UniProt P08637 topology). HPA gives no main ICC-IF location or cell-line images, so the supplied record cannot validate a specific IF appearance (HPA: subcellular record). |
| Chromogenic background | Endogenous enzyme activity can contribute signal in chromogenic IHC; assess it with appropriate staining controls and blocking for the chosen detection chemistry (general IHC practice). This is a workflow consideration, not an FCGR3A-specific effect. |
| Situation | Likely cause | Next action |
|---|---|---|
| Lung macrophages show no staining. | A run failure, insufficient detection or difficulty identifying macrophages may explain the discrepancy; HPA reports these cells as High (HPA: lung macrophages). | Check the positive-control section, primary-antibody incubation and detection reagents, then reassess cell identity (general IHC practice). |
| Most cells show a faint, even chromogenic haze. | Nonspecific background or residual detection activity may obscure a subset pattern (general IHC practice); HPA describes expression in a subset of cells (HPA: tissue IHC). | Inspect the no-primary control; review blocking, washing and detection development for the chosen assay (general IHC practice). |
| Bronchial respiratory epithelial cells stain prominently. | This differs from the HPA Not detected observation for that cell type (HPA: bronchus respiratory epithelial cells); specificity or detection background needs assessment. | Compare positive tissue and no-primary controls, then check whether staining follows cell type or a section-wide background pattern (general IHC practice). |
| Signal appears only in nuclei. | A nuclear-only pattern conflicts with the supplied membrane and cytoplasmic descriptions (UniProt P08637 subcellular location; HPA: tissue IHC). | Review staining controls and morphology; withhold an FCGR3A-positive call until the expected cell distribution is demonstrated (general IHC practice). |
| Lymph node looks weaker than lung or spleen. | HPA records Low staining in lymph-node non-germinal-center cells, versus High in lung macrophages and splenic red-pulp cells (HPA: tissue IHC). | Identify the stained cell population and compare it with its own HPA category before changing assay conditions (HPA: tissue IHC; general IHC practice). |
| An IF/ICC result differs from the paraffin-section IHC pattern. | The supplied HPA subcellular record has no main ICC-IF location or cell-line images, and neither listed antibody has an ICC status (HPA: subcellular record; antibody validation). | Treat the IF result as unvalidated by these records; assess its localisation and controls within an IF-specific experiment (UniProt P08637 topology; general IF practice). |
Experiment evidence
IHC & IF images showing FCGR3A staining
A01408-1 · IHCIHC analysis of CD16 using anti-CD16 antibody (A01408-1). CD16 was detected in a paraffin-embedded section of human liver cancer tissue. Hea
A01408-1 · IHCIHC analysis of CD16 using anti-CD16 antibody (A01408-1). CD16 was detected in a paraffin-embedded section of human rectal cancer tissue. He
A01408-1 · IFIF analysis of CD16 using anti-CD16 antibody (A01408-1). CD16 was detected in an immunocytochemical section of K562 cells. Enzyme antigen re
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000203747-FCGR3A/tissue/cerebral+cortex#imid_8514936
HPA · LungHuman Protein Atlas IHC, Lung. Source: https://www.proteinatlas.org/ENSG00000203747-FCGR3A/tissue/lung#imid_8514815
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000203747-FCGR3A/tissue/colon#imid_8514870
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000203747-FCGR3A/tissue/liver#imid_8514863
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for FCGR3A IHC & IF
🧪Run lung first and look for staining in macrophages (HPA: High in lung macrophages); use bronchus respiratory epithelial cells as the negative tissue comparator (HPA: Not detected in bronchus respiratory epithelial cells). On the lung slide, adjacent non-macrophage cells should show only background-level DAB before they are treated as internal negatives (HPA: High in lung macrophages).
Positive control tissue: Lung (Macrophages, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for FCGR3A; derive a cell-line control from the positive tissue's cell type (Macrophages) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only section, a host- and clonality-matched rabbit IgG isotype control, and FCGR3A knockout material or peptide competition if the immunizing peptide is available (selected IHC caption: rabbit primary; standard IHC practice). For lung DAB staining, quench endogenous peroxidase and check macrophage pigment; block endogenous biotin if using the caption’s streptavidin–biotin detection (selected IHC caption: SABC with DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the fixative for the selected A01408-1 paraffin-section caption is unreported (selected IHC caption). That caption uses heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required; the supplied evidence does not establish whether frozen sections or IF are easier (selected IHC caption; HPA subcellular: no ICC-IF images). Lung macrophage pigment and endogenous peroxidase can complicate DAB interpretation, so compare their signal with the no-primary section (standard IHC practice).
HPA tissue IHC evidence for FCGR3A
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex. External characterization data supports antibody staining.). 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 |
|---|---|---|---|---|
| Lung | Macrophages | High | Protein (IHC) | HPA → |
| Placenta | Hofbauer cells | High | Protein (IHC) | HPA → |
| Skin | Fibrohistiocytic cells | Medium | Protein (IHC) | HPA → |
| Spleen | Cells in red pulp | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | 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 → |
| Appendix | Glandular 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 FCGR3A IHC Tips
Troubleshoot FCGR3A staining in paraffin sections by checking retrieval, cell identity, compartment, controls, and scoring against the supplied tissue evidence.
What retrieval should I try when FCGR3A staining is weak in paraffin sections?
Start with heat-mediated retrieval in EDTA at pH 8.0 (datasheet A01408-1). The selected paraffin-section image used this retrieval before overnight incubation with 2 μg/ml primary antibody at 4°C (datasheet A01408-1). If staining remains weak, vary heating time on adjacent sections while keeping buffer and antibody concentration fixed, then compare signal with tissue integrity (standard IHC practice). Include a section with an expected positive cell population, such as lung macrophages (HPA: High in lung macrophages), and a no-primary control (standard IHC practice). Record whether stronger staining follows the expected cell distribution before adopting a harsher retrieval condition (HPA tissue IHC; standard IHC practice).
Could fixation explain weak or uneven FCGR3A staining?
Target-specific sensitivity to fixation is unknown: the selected paraffin-section caption does not state a fixative (datasheet A01408-1). Document the specimen’s actual fixative and fixation duration, and compare sections processed under known conditions before attributing a difference to FCGR3A (standard IHC practice). Keep retrieval at EDTA pH 8.0 and the tested primary concentration at 2 μg/ml while assessing that difference (datasheet A01408-1). Check whether weak staining affects the whole section or follows poorly preserved areas, and review tissue morphology alongside the no-primary control (standard IHC practice). A change in staining across specimens cannot establish an FCGR3A-specific fixation effect without a controlled comparison (standard IHC practice).
Should FCGR3A staining appear on membranes or in cytoplasm?
FCGR3A has an extracellular region at residues 17–208, a transmembrane segment at 209–229, and a cytoplasmic tail at 230–254 (UniProt P08637 topology). Membrane-associated staining is therefore anatomically plausible, while a soluble receptor also exists (UniProt P08637 subcellular annotation). HPA reports cytoplasmic staining in subsets of cells, including lung macrophages and liver Kupffer cells (HPA tissue IHC profile). Score the observed membrane and cytoplasmic patterns separately, with reference to cell morphology and appropriate controls (standard IHC practice). Diffuse staining across unrelated cells needs further specificity checks before it is treated as receptor localisation (standard IHC practice).
How do I assess epitope accessibility and antibody specificity?
The supplied record lists 0 isoforms, so an isoform-specific explanation for divergent staining is unsupported here (UniProt P08637 isoform record). Its extracellular region spans residues 17–208 and contains two Ig-like domains, while the cytoplasmic tail spans 230–254 (UniProt P08637 topology and domains). Five glycosylation sites lie in the extracellular region, and phosphorylation sites are reported at 236 and 237 (UniProt P08637 modifications). The antibody’s precise epitope is not supplied (datasheet A01408-1 evidence supplied), so do not assign retrieval effects to either modification. Compare expected cell distribution, staining pattern, and an independent specificity control before interpreting an unusual signal (standard IHC practice).
How should I investigate an FCGR3A pattern with multiplex IF?
Use IF as a supporting comparison to the chromogenic section and include a marker for an expected cell population, such as macrophages or NK cells (HPA: High in lung macrophages; UniProt P08637 tissue specificity). Choose fluorophores after checking tissue autofluorescence in an unstained section, and separate their emission from the nuclear counterstain (standard IF practice). FCGR3A’s extracellular region is 17–208 and its cytoplasmic tail is 230–254 (UniProt P08637 topology). If the antibody binds an extracellular epitope, minimise permeabilisation; a cytoplasmic epitope requires permeabilisation, but the supplied antibody epitope is unspecified (UniProt P08637 topology; datasheet A01408-1 evidence supplied; standard IF practice). Confirm cell identity and compartment in the chromogenic IHC result independently (standard IHC practice).
How can I separate FCGR3A signal from chromogenic background?
The selected image used 10% goat serum blocking, a biotinylated secondary antibody, a streptavidin–biotin complex, and DAB (datasheet A01408-1). Compare a no-primary section and, when using that detection scheme, controls for secondary or biotin-related background (standard IHC practice). Apply a peroxidase block before DAB development and inspect whether residual colour follows tissue structures rather than expected positive cells (standard chromogenic IHC practice). FCGR3A binds antigen-complexed IgG, so review staining that follows immune deposits or broadly IgG-rich regions with particular care (UniProt P08637 function; standard IHC practice). Shorten chromogen development only after checking that expected positive cells remain detectable (standard IHC practice).
What should I quantify when FCGR3A-positive cells are sparse? ⚠ ANSWER MARKED FOR VERIFICATION
Define the tissue compartment and expected cell class before scoring, because HPA describes staining in subsets rather than uniformly across tissue (HPA tissue IHC profile). Report the percentage of positive eligible cells and, when cell abundance varies, positive-cell density per mm² of viable tissue (standard IHC quantification practice). An H-score can summarise intensity and percentage within that same defined cell class, but specify the scoring thresholds used (standard IHC quantification practice). Normalise to eligible cells or viable tissue area, and record excluded necrotic regions and section-edge artefacts (standard IHC quantification practice). Keep membrane and cytoplasmic scores separate if both patterns occur (UniProt P08637 subcellular annotation; HPA tissue IHC profile).
When is an FCGR3A-positive cell convincing rather than an artefact?
A convincing result follows a plausible cell distribution, such as lung macrophages or liver Kupffer cells, rather than indiscriminate staining of every cell (HPA tissue IHC profile). Membrane signal is compatible with the transmembrane receptor, and cytoplasmic signal has been reported in tissue IHC (UniProt P08637 topology; HPA tissue IHC profile). Check apparently positive cells against morphology and a no-primary section before assigning identity or compartment (standard IHC practice). Treat signal restricted to section edges, necrotic areas, or residual endogenous enzyme activity as suspect until controlled (standard IHC practice). Because a soluble receptor also exists, extracellular colour alone does not establish expression by the adjacent cell (UniProt P08637 subcellular annotation; standard IHC interpretation).
Boster reagents
Best FCGR3A / Low affinity immunoglobulin gamma Fc region receptor III-A IHC Antibodies
A01408-1 has IHC images from human paraffin sections and an IF image from K562 cells (A01408-1 image captions). M01408-1 lists human, mouse and rat reactivity (catalog).
Real IHC data
Anti-CD16/FCGR3A Antibody
Cat # A01408-1
A01408-1 will render with its own IHC figure from a paraffin-embedded human liver cancer section (A01408-1 IHC image caption). Its catalog also documents IHC in human rectal cancer paraffin sections and IF in K562 cells (A01408-1 image captions).
Which to pick: Choose A01408-1 for tissue IHC: its own figure documents a paraffin-embedded human section, with no fixative reported (A01408-1 IHC image caption). For IF/ICC, A01408-1 has a K562 IF image (A01408-1 IF image caption). For human, mouse or rat IF/ICC, M01408-1 is a rabbit monoclonal option on the application and reactivity lists; IHC is not listed for it (M01408-1 catalog).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P08637 (FCG3A_HUMAN, Low affinity immunoglobulin gamma Fc region receptor III-A).
- Human Protein Atlas. FCGR3A tissue IHC expression (reliability: Supported).
- Human Protein Atlas. FCGR3A subcellular location (ICC-IF): Membrane, Secreted.
- Human Protein Atlas. FCGR3A antibody validation summary (2 antibodies).
- The macrophage colony-stimulating factor 1 response signature in breast carcinoma. Clinical cancer research : an official journal of the American Association for Cancer Research 2009 — PMC2987696.
- Analysis of stromal signatures in the tumor microenvironment of ductal carcinoma in situ. Breast cancer research and treatment 2010 — PMC2976659.
- Variations in stromal signatures in breast and colorectal cancer metastases. The Journal of pathology 2010 — PMC2935495.
- Prognostic significance and gene co-expression network of CD16A and FGL2 in gliomas. Frontiers in oncology 2024 — PMC11611834.
- PubMed PMID:2526846 — UniProt-cited evidence.
- PubMed PMID:16951347 — UniProt-cited evidence.
- PubMed PMID:16710414 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for FCGR3A (Low affinity immunoglobulin gamma Fc region receptor III-A). Expected localisation Cytoplasmic in tissue (HPA tissue IHC); cell membrane (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A01408-1). Validated IHC antibody: A01408-1 at 2-5μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Lung (Macrophages); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet A01408-1); 2. Fixation: Image fixative and duration unreported (datasheet A01408-1); 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 retrieval: EDTA pH 8.0 (datasheet A01408-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A01408-1); 8. Primary antibody: Rabbit anti-FCGR3A, 2-5μg/ml (datasheet A01408-1); 9. Primary incubation: Overnight at 4 °C (datasheet A01408-1). Watch for: Fixation: Keep section fixation consistent (standard IHC practice; not target-specific); Caveat: Soluble receptor may complicate cell assignment (UniProt); Isoform / epitope: No isoforms annotated; epitope side affects accessibility (UniProt); Regulation: Regulation not specified in the record (UniProt). Evidence: UniProt P08637, HPA tissue IHC · Supported, HPA ICC-IF · Membrane, Secreted, Datasheet A01408-1, PMC2987696, PMC2976659. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/FCGR3A/immunohistochemistry-ihc-guide.