CD7 / T-cell antigen CD7 · IHC design guide

Design Immunohistochemistry for CD7

Plan paraffin-section CD7 IHC with a starting antibody range of 0.5–1 µg/mL (datasheet A01974-2). Interpret staining in immune-cell subsets against the tissue profile (HPA tissue IHC), accounting for CD7 expression in both T cells and NK cells (UniProt).

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

Immunohistochemistry protocol sheet for CD7 (IHC for CD7): expected localisation Observed cytoplasmic (HPA tissue IHC); membrane protein (UniProt), antibody A01974-2, validated IHC image, and IHC protocol steps — Printable **CD7** IHC protocol sheet — expected localisation Observed cytoplasmic (HPA tissue IHC); membrane protein (UniProt), antibody A01974-2, controls and protocol steps. Open the full CD7 IHC guide →

Navigate to: Protocols Staining pattern Controls Antibodies

CD7 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	Observed cytoplasmic (HPA tissue IHC); membrane protein (UniProt)
	Staining pattern	Cytoplasmic staining in a subset of immune cells (HPA tissue IHC)
	Antigen retrieval	Citrate pH 6 HIER, heat-mediated (datasheet A01974-2)
	Positive control ⓘ	Appendix+2 more · see all
	Negative control ⓘ	Adipose tissue+4 more · see all

Important caveats

Reasons your staining may differ from the expected pattern.

	Fixation	Keep paraffin-section fixation consistent. (standard IHC practice; not target-specific)
	Caveat	NK cells also express CD7; staining is not T-cell-specific (UniProt)
	Regulation	No expression regulation specified (UniProt)
	Isoform / epitope	0 isoforms; epitope side may be extracellular or cytoplasmic (UniProt)

Section 1

Recommended CD7 IHC & IF Protocols

The catalog antibody protocol is paired with two published CD7 IHC protocols: human melanoma tissue (PMC3961532) and tumor tissue harvested from mice (PMC6299443).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A01974-2)
Fixation	Image fixative and duration unreported (datasheet A01974-2); verify before use.
Sectioning	4–5 µm sections on charged slides (standard)
Deparaffinisation	Xylene, graded ethanol series to water (standard)
Antigen retrieval	Heat retrieval: Citrate pH 6, 20 min (datasheet A01974-2)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% goat serum (datasheet A01974-2)
Primary antibody	Rabbit anti-CD7, 0.5-1μg/ml (datasheet A01974-2)
Primary incubation	Overnight at 4 °C (datasheet A01974-2)
Detection	Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A01974-2)
Counterstain	Hematoxylin, blue, dehydrate and mount (standard)
Expected result	CD7-positive staining in non-germinal center cells of appendix (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in a subset of immune cells. No signal in the no-primary control.

💡Decision noteStart with citrate pH 6 heat retrieval, as specified by the catalog datasheet and used in both published protocols (datasheet: A01974-2; PMC3961532; PMC6299443).

Section 2

What Is the Expected CD7 Staining Pattern?

CD7 is a membrane protein with an extracellular region at residues 26–180 and a transmembrane segment at 181–201 (UniProt P09564 topology). It is expressed on T cells, NK cells and their precursors (UniProt P09564 tissue specificity). In tissue IHC, expect staining in a subset of immune cells; HPA describes the observed pattern as cytoplasmic and rates its tissue staining reliability Enhanced (HPA tissue IHC).

What am I looking at on my slide?
Discrete staining in non-germinal center cells of appendix or tonsil.	This fits HPA's High staining in those cell populations (HPA tissue IHC). Evaluate the labeled cells within the tissue architecture: UniProt supports CD7 expression on T and NK cells and their precursors, but the HPA tissue entry does not identify every stained cell individually (UniProt P09564 tissue specificity; HPA tissue IHC).
Staining appears at cell borders or within the cytoplasmic area of a subset of immune cells.	A membrane-associated result is consistent with CD7 topology, while HPA describes its tissue IHC profile as cytoplasmic in a subset of immune cells (UniProt P09564 topology; HPA tissue IHC). Interpret the visible compartment together with cell identity and the control tissue; a cytoplasmic appearance alone does not establish an artifact.
Prominent nuclear staining, with little staining in the expected immune-cell population.	Nuclear localization conflicts with the recorded membrane localization and HPA's immune-cell tissue profile (UniProt P09564 subcellular location; HPA tissue IHC). Treat a predominantly nuclear result as suspect. Reassess staining and detection conditions and compare it with a known-positive tissue before scoring nuclei as CD7-positive.
Broad staining of adipocytes or respiratory epithelial cells.	HPA reports CD7 as not detected in adipocytes of adipose tissue and respiratory epithelial cells of bronchus (HPA tissue IHC). If these cells stain broadly, consider nonspecific antibody binding or endogenous detection activity. Check whether the signal follows tissue structures or appears in a control lacking primary antibody.
No convincing signal in non-germinal center cells of appendix or tonsil.	That disagrees with HPA's High staining in those populations (HPA tissue IHC). First confirm that the expected cells are present in the section. Then review the IHC workflow, antibody concentration and detection controls; absence of signal in one preparation does not establish absence of CD7 from the tissue.

💡Expected CD7 appearanceCall a result positive when a subset of immune cells shows distinct membrane-associated or cytoplasmic-area staining, especially High staining in appendix or tonsil non-germinal center cells (UniProt P09564 topology; HPA tissue IHC); widespread staining of HPA-negative adipocytes or respiratory epithelium is suspect (HPA tissue IHC).

How each factor affects the staining
Cell population and control tissue	Appendix and tonsil non-germinal center cells are High; spleen red-pulp cells are Medium; lymph-node non-germinal center and bone-marrow hematopoietic cells are Low (HPA tissue IHC). Choose and interpret controls with those different observed levels in mind.
Topology and compartment	CD7 has an extracellular region at residues 26–180, a membrane span at 181–201 and a cytoplasmic region at 202–240 (UniProt P09564 topology). HPA summarizes tissue IHC staining as cytoplasmic in a subset of immune cells (HPA tissue IHC); assess both observations without assigning an unreported antibody epitope.
Protein processing and modification	The precursor has a signal peptide at residues 1–25, and glycosylation sites are recorded at residues 45 and 96 (UniProt P09564 processing; glycosylation). These features describe the protein but provide no evidence here that a particular retrieval condition or fixation interval changes CD7 staining.
Antibody validation	HPA lists IHC status as Enhanced for antibodies HPA039079 and CAB002594, alongside an Enhanced tissue reliability assessment (HPA antibodies; HPA tissue IHC). These entries support the reported tissue pattern; they do not validate an unlisted catalog antibody or specify its dilution.
Q: What should IF/ICC show?	A: Membrane localization is supported by UniProt and the HPA subcellular summary (UniProt P09564 subcellular location; HPA subcellular). HPA provides no ICC-IF image cell lines or main-location entry, and neither listed HPA antibody has an ICC validation status (HPA subcellular; HPA antibodies).

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
Positive tissue has no staining.	The result conflicts with High staining in appendix or tonsil non-germinal center cells (HPA tissue IHC); the cause cannot be assigned from that observation alone.	Confirm the expected cells are in the section, then review the catalog antibody's IHC-P instructions, primary-antibody use and detection controls. Compare with another known-positive section before interpreting the result as CD7-negative.
Only faint staining appears in lymph node or bone marrow.	HPA records Low staining in lymph-node non-germinal center cells and bone-marrow hematopoietic cells (HPA tissue IHC). A faint result there may reflect the reported pattern.	Use an HPA High population in appendix or tonsil for a clearer positive comparison (HPA tissue IHC). Judge the faint population against background and cell morphology before calling the assay unsuccessful.
Nuclei dominate the signal.	Predominantly nuclear staining is inconsistent with CD7's recorded membrane localization and HPA's immune-cell staining profile (UniProt P09564 subcellular location; HPA tissue IHC).	Review the primary antibody and detection steps, inspect a known-positive tissue, and score only a reproducible pattern in the expected cell population. Do not count isolated nuclear signal as established CD7 localization.
Most cells or the whole section have diffuse color.	Diffuse signal prevents assessment of the subset-of-immune-cells profile reported for CD7 (HPA tissue IHC). Nonspecific binding, insufficient blocking or endogenous detection activity are general IHC possibilities.	Compare with a control lacking primary antibody. Review blocking, washing and chromogen development as general IHC checks; then reassess whether discrete immune cells remain above background.
Adipocytes or bronchial respiratory epithelium stain strongly.	HPA reports CD7 as not detected in those cell populations (HPA tissue IHC). Such staining raises concern for cross-reactivity or endogenous detection activity, without identifying which is responsible.	Compare the suspect cells with a no-primary control and an expected positive immune-cell population. Review antibody concentration and detection blocking as general IHC checks before reporting those cells as positive.
The IHC pattern is being used to predict an IF/ICC result.	HPA's subcellular summary says membrane, but it lists no ICC-IF image cell lines; the two listed antibodies have no ICC status (HPA subcellular; HPA antibodies).	Treat membrane localization as the biological expectation (UniProt P09564 topology). Assess IF/ICC controls on its own guide page; do not treat the IHC tissue images as IF/ICC validation.

Source: UniProt P09564 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing CD7 staining

IHC analysis of CD7 using anti-CD7 antibody (A01974-2). CD7 was detected in paraffin-embedded section of human tonsil tissue . Heat mediated antigen retrieval was performed in citrate buffer (pH6, epitope retrieval solution) for 20 mins. The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 1μg/ml rabbit anti-CD7 Antibody (A01974-2) overnight at 4°C. Biotinylated goat anti-rabbit IgG was used as secondary antibody and incubated for 30 minutes at 37°C. The tissue section was developed using Strepavidin-Biotin-Complex (SABC)(Catalog # SA1022) with DAB as the chromogen.

A01974-2 · IHCIHC analysis of CD7 using anti-CD7 antibody (A01974-2). CD7 was detected in paraffin-embedded section of human tonsil tissue . Heat mediated

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000173762-CD7/tissue/cerebral+cortex#imid_16507119

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000173762-CD7/tissue/colon#imid_16507053

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000173762-CD7/tissue/liver#imid_16507046

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000173762-CD7/tissue/kidney#imid_16507047

← swipe / scroll for more images →

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

Sample controls for CD7 IHC & IF

🧪Run tonsil first and look for CD7 staining in non-germinal center cells (HPA: High in tonsil non-germinal center cells). Use adipose tissue as a negative comparator, checking that adipocytes and other cells identified as CD7-negative lack specific membrane staining; do not assume every cell outside the positive population is negative because CD7 is expressed on T and NK cells (HPA: Not detected in adipocytes; UniProt P09564: membrane localization and T/NK-cell expression).

Positive control tissue: Appendix (Non-germinal center cells, 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 CD7; derive a cell-line control from the positive tissue's cell type (Non-germinal center cells) and confirm it by RNA or western blot first.

Technical controls: Include a no-primary (secondary-only) slide, a rabbit IgG isotype control matched to the primary antibody’s clonality where applicable, and a CD7 knockout sample or peptide competition control if available (hero caption: rabbit anti-CD7 antibody; standard IHC controls). Quench endogenous peroxidase and assess endogenous biotin background in tonsil when using the caption’s streptavidin–biotin/DAB detection (hero caption: tonsil and SABC/DAB detection; standard chromogenic IHC practice).

⚠️Feasibility: The selected paraffin-section caption uses citrate retrieval at pH 6 for 20 minutes, but it does not establish that retrieval is required (hero caption: citrate retrieval). A target-specific fixation window or fixation effect is unreported, and the selected-SKU caption does not state the fixative (hero caption: fixative not stated). Paraffin IHC has direct caption support; no matched frozen-section or IF/ICC evidence establishes either as easier, and tonsil background from endogenous peroxidase or biotin needs checking with the stated detection method (hero caption: tonsil SABC/DAB; HPA subcellular: no ICC-IF image cell lines).

HPA tissue IHC evidence for CD7

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High 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
Appendix	Non-germinal center cells	High	Protein (IHC)	HPA →
Tonsil	Non-germinal center cells	High	Protein (IHC)	HPA →
Spleen	Cells in red pulp	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 →
Breast	Adipocytes	Not detected	Protein (IHC)	HPA →
Bronchus	Respiratory epithelial cells	Not detected	Protein (IHC)	HPA →
Caudate	Glial cells	Not detected	Protein (IHC)	HPA →

Section 3

Advanced CD7 IHC Tips

Troubleshoot CD7 staining in paraffin sections using the catalog antibody’s tissue example and expected immune cell distribution (datasheet A01974-2; UniProt P09564; HPA tissue IHC).

What retrieval should I try first when CD7 staining is weak in paraffin sections?

Start with heat mediated retrieval in citrate buffer at pH 6 for 20 minutes (datasheet A01974-2). This condition was used for the catalog antibody in a human tonsil paraffin section; the caption does not report its fixative (datasheet A01974-2). Keep section thickness, heating, and cooling consistent when comparing runs, since each can change staining and tissue morphology (standard IHC practice). If signal remains weak, compare a modestly longer heating time on matched sections, then assess background and morphology before adjusting the primary antibody concentration (standard IHC practice).

Could fixation explain variable CD7 staining between paraffin blocks?

Target specific fixation sensitivity is unknown: the catalog tissue caption describes a paraffin section but does not state its fixative (datasheet A01974-2). Record each block’s fixative and fixation duration before comparing staining, because those processing differences can affect antigen accessibility in routine IHC (standard IHC practice). Run matched control sections through the same citrate pH 6, 20 minute retrieval and detection workflow when assessing variability (datasheet A01974-2; standard IHC practice). If one block stains poorly, check section integrity and processing records before attributing the result to altered CD7 expression (standard IHC practice).

Should CD7 appear on the membrane or in the cytoplasm of stained cells?

CD7 is a membrane protein with an extracellular region at residues 26–180, a transmembrane segment at 181–201, and a cytoplasmic tail at 202–240 (UniProt P09564 topology). The HPA tissue IHC profile nevertheless describes cytoplasmic staining in a subset of immune cells, so compare the observed pattern with the assay and tissue control rather than demanding a crisp membrane rim (HPA tissue IHC). Inspect staining at high magnification to distinguish cell associated signal from diffuse precipitate or pigment (standard IHC practice). In tonsil, assess immune cells in non germinal center regions against nearby unstained cells (HPA: Tonsil, high in non-germinal center cells; standard IHC practice).

How do epitope location and glycosylation affect a CD7 IHC result?

The record lists 0 isoforms, so it provides no basis for explaining discordant IHC staining as an isoform switch (UniProt P09564). CD7 has an Ig like extracellular region at residues 26–130 and glycosylation sites at residues 45 and 96 (UniProt P09564). The supplied caption does not identify the catalog antibody’s epitope, so do not assume whether it binds the extracellular region or cytoplasmic tail (datasheet A01974-2). If staining changes after retrieval or processing changes, compare matched sections and controls before assigning the difference to epitope masking or glycosylation (standard IHC practice).

How should I assess CD7 in a multiplex IF experiment?

Use a marker for the expected T cell or NK cell population to assess CD7 colocalisation, while allowing for CD7 expression in their precursors (UniProt P09564; standard IF practice). Choose a fluorophore in a channel with low tissue autofluorescence, and examine an unstained section under the same exposure settings (standard IF practice). CD7 spans the membrane, with extracellular residues 26–180 and a cytoplasmic tail at 202–240; permeabilisation needs depend on which side contains the antibody epitope (UniProt P09564 topology; standard IF practice). Because the supplied catalog caption documents chromogenic paraffin IHC and does not identify the epitope, establish IF conditions with appropriate controls (datasheet A01974-2; standard IF practice).

How can I reduce diffuse brown staining without losing CD7 positive cells?

The catalog tonsil example used 10% goat serum blocking, 1 µg/mL primary antibody overnight at 4°C, and DAB detection through a biotin based system (datasheet A01974-2). Use a no primary control to locate signal from detection reagents, and verify that the peroxidase block is effective before interpreting brown staining (standard IHC practice). If background persists, compare lower primary concentrations or shorter incubation on matched sections while retaining an immune cell positive control (standard IHC practice; UniProt P09564 tissue specificity). Inspect precipitate at section edges and in damaged areas separately from cell associated staining (standard IHC practice).

How should I quantify CD7 when immune cell abundance differs between sections? ⚠ ANSWER MARKED FOR VERIFICATION

Define the tissue region and cell population before scoring, because CD7 expression is associated with T cells, NK cells, and their precursors (UniProt P09564 tissue specificity; standard IHC practice). Report the percentage of positive immune cells, or count positive cells per mm² of evaluable tissue using a consistent positivity threshold (standard IHC practice). If staining intensity is reproducible, an H score can combine positive cell fractions with intensity categories; record the denominator and scoring rules (standard IHC practice). Normalise comparisons to the relevant immune cell population or sampled tissue area, and exclude folds, necrosis, and section edges consistently (standard IHC practice).

Which CD7 staining patterns suggest a true signal rather than artefact?

Favor staining in the expected immune cell population: CD7 is expressed by T cells, NK cells, and their precursors (UniProt P09564 tissue specificity). In tonsil, non germinal center cells provide a reported high staining reference, while the HPA tissue profile describes cytoplasmic signal in a subset of immune cells (HPA tissue IHC). Review apparent staining in unrelated cells, diffuse extracellular deposits, section edges, and necrotic areas against morphology and a no primary control (standard IHC practice). Brown signal from endogenous peroxidase or the detection system should be investigated with appropriate controls before calling additional CD7 positive cells (standard IHC practice).

Boster reagents

Best CD7 / T-cell antigen CD7 IHC Antibodies

Human-reactive anti-CD7 antibodies are listed for IHC and ICC/IF (catalog: A01974-2 and M01974 applications/reactivity). A paraffin-section IHC image is supplied for A01974-2 (A01974-2 image caption).

Real IHC data

Anti-CD7 Antibody ®

Cat # A01974-2

View product →

A01974-2 is listed for human IHC and ICC, with an IHC image from a human tonsil paraffin section (catalog: A01974-2 applications/reactivity; A01974-2 image caption). M01974 is listed for human IHC and ICC/IF, with no IHC or IF image supplied (catalog: M01974 applications/reactivity/image alts).

Which to pick: For tissue IHC, choose A01974-2: its paraffin-section image documents citrate retrieval at pH 6 and 1 μg/ml primary antibody; the fixative is unreported (A01974-2 image caption). For IF/ICC, M01974 is a rabbit monoclonal, clone ADIG-3, with ICC/IF listed but no IF image supplied (catalog: M01974 host/clone/applications/if_image_alts). Neither SKU has documented cross-species reactivity here; both list Human only (catalog: A01974-2 and M01974 reactivity).

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

References

UniProt Consortium. UniProt entry P09564 (CD7_HUMAN, T-cell antigen CD7).
Human Protein Atlas. CD7 tissue IHC expression (reliability: Enhanced).
Human Protein Atlas. CD7 subcellular location (ICC-IF): Membrane.
Human Protein Atlas. CD7 antibody validation summary (2 antibodies).
Prognostic Value of Immunohistochemical T-Cell Marker Loss in Early-Stage Mycosis Fungoides: A Single-Center Cohort Study. Dermatopathology (Basel, Switzerland) 2025 — PMC12452609.
SECTM1 produced by tumor cells attracts human monocytes via CD7-mediated activation of the PI3K pathway. The Journal of investigative dermatology 2014 — PMC3961532.
Naturally selected CD7 CAR-T therapy without genetic editing demonstrates significant antitumour efficacy against relapsed and refractory acute myeloid leukaemia (R/R-AML). Journal of translational medicine 2022 — PMC9753314.
T-cell functionality testing is highly relevant to developing novel immuno-tracers monitoring T cells in the context of immunotherapies and revealed CD7 as an attractive target. Theranostics 2018 — PMC6299443.
PubMed PMID:3501369 — UniProt-cited evidence.
PubMed PMID:1703303 — UniProt-cited evidence.
PubMed PMID:15489334 — UniProt-cited evidence.