TAP1 / Antigen peptide transporter 1 · IHC design guide

Design Immunohistochemistry for TAP1

Plan TAP1 paraffin-section IHC using its observed granular cytoplasmic pattern (HPA tissue IHC) and ER membrane location (UniProt). This guide covers fixation, staining controls and cell-type-aware scoring (standard IHC practice).

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

Immunohistochemistry protocol sheet for TAP1 (IHC for TAP1): expected localisation Granular cytoplasm (HPA tissue IHC); ER membrane (UniProt), antibody PB9823, validated IHC image, and IHC protocol steps — Printable **TAP1** IHC protocol sheet — expected localisation Granular cytoplasm (HPA tissue IHC); ER membrane (UniProt), antibody PB9823, controls and protocol steps. Open the full TAP1 IHC guide →

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TAP1 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	Granular cytoplasm (HPA tissue IHC); ER membrane (UniProt)
	Staining pattern	Granular cytoplasmic staining across multiple cell types (HPA tissue IHC)
	Antigen retrieval	EDTA pH 8.0 HIER, heat-mediated (datasheet PB9823)
	Positive control ⓘ	Adrenal gland+4 more · see all
	Negative control ⓘ	None in HPA (detected in all 45 tissues); use no-primary + isotype controls

Important caveats

Reasons your staining may differ from the expected pattern.

	Fixation	Keep paraffin-section fixation consistent (standard IHC practice; not target-specific)
	Caveat	High hematopoietic-cell staining may complicate scoring (HPA tissue IHC)
	Regulation	Expression regulation not specified (UniProt)
	Isoform / epitope	2 isoforms; epitope coverage is unspecified (UniProt)

Section 1

Recommended TAP1 IHC & IF Protocols

The catalog antibody protocol uses EDTA pH 8.0 retrieval (datasheet: PB9823). The two published IHC protocols below provide tissue-specific staining conditions (PMC5706630; PMC7171417).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human intestinal cancer tissue; fixative not specified (datasheet PB9823)
Fixation	Image fixative and duration unreported (datasheet PB9823); 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 PB9823); 20 min, 95–100 °C (standard)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% goat serum (datasheet PB9823)
Primary antibody	Rabbit anti-TAP1, 0.5-1μg/ml (datasheet PB9823)
Primary incubation	Overnight at 4 °C (datasheet PB9823)
Detection	Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9823)
Counterstain	Hematoxylin, blue, dehydrate and mount (standard)
Expected result	TAP1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression with a granular pattern. No signal in the no-primary control.

💡Decision noteTry heat-mediated EDTA pH 8.0 retrieval first for the catalog antibody (datasheet: PB9823); the hepatocellular carcinoma protocol used heated citrate pH 6.0 (PMC7171417).

Section 2

What Is the Expected TAP1 Staining Pattern?

TAP1 is an endoplasmic reticulum (ER) membrane protein with 10 transmembrane segments (UniProt Q03518 topology). In paraffin-section IHC, expect granular cytoplasmic staining (HPA tissue IHC: general cytoplasmic granular pattern). Interpret signal in the context of the cells present: UniProt reports high expression in professional antigen-presenting cells and lymphocyte subsets, while HPA reports high staining in several epithelial, glandular, endothelial, and hematopoietic cell populations (UniProt Q03518 tissue specificity; HPA tissue IHC: High). HPA rates the tissue IHC profile Approved, with medium consistency between staining and RNA data (HPA tissue IHC: reliability).

What am I looking at on my slide?
Granular cytoplasmic staining in glandular cells or marrow hematopoietic cells, with recognizable tissue structure.	This fits the reported tissue pattern and an ER-associated target (HPA tissue IHC: general cytoplasmic granular pattern; HPA tissue IHC: High in glandular and bone marrow hematopoietic cells; UniProt Q03518 subcellular location). Compare cells within the same section before assigning a score: HPA reports low tissue specificity at the RNA level, so staining need not be confined to one lineage (HPA tissue IHC: RNA specificity).
Predominantly nuclear, extracellular, or sharply cell-surface staining without a granular cytoplasmic component.	Treat this as a compartment mismatch requiring verification: the reported IHC pattern is cytoplasmic and granular, and UniProt places TAP1 in the ER membrane (HPA tissue IHC: profile; UniProt Q03518 subcellular location). Check the antibody's IHC validation and the slide controls before calling the pattern TAP1-specific (HPA antibodies: IHC Approved for CAB009516; general IHC practice).
Strong colour appears mainly in a cell population unexpected for the chosen tissue, while expected cells remain unstained.	Consider cross-reactivity or endogenous detection activity as possible causes, then compare a reagent control and tissue morphology (general IHC practice). Do not classify a cell as wrong solely because it is absent from HPA's short positive list: HPA reports low tissue RNA specificity and lists no negative cell populations here (HPA tissue IHC: RNA specificity; HPA tissue IHC: negative list).
A diffuse haze covers cells and surrounding tissue, obscuring granular detail.	Score the field cautiously: haze does not reproduce the reported granular cytoplasmic profile (HPA tissue IHC: profile). Review blocking, washing, antibody concentration, and chromogen development with appropriate controls; these are general IHC background checks, not documented TAP1-specific effects (general IHC practice).
No detectable staining in a section expected to contain HPA high-staining cells.	First confirm that the expected cells are actually present and that the run's positive control developed (general IHC practice). HPA reports high staining in adrenal gland glandular cells and bone marrow hematopoietic cells, among other examples; a blank result there merits review of antibody suitability and the IHC workflow, but does not by itself prove TAP1 absence (HPA tissue IHC: High; HPA antibodies: IHC Approved for CAB009516).

💡Expected TAP1 appearanceCall a result consistent with TAP1 when staining is granular and cytoplasmic in the relevant cells, including HPA high-staining populations; prominent isolated nuclear or extracellular colour is a pattern mismatch that needs control review (HPA tissue IHC: profile and High; UniProt Q03518 subcellular location; general IHC practice).

How each factor affects the staining
ER location and membrane topology	TAP1 occupies the ER membrane and has 10 transmembrane segments (UniProt Q03518 subcellular location and topology). Use that location to interpret a granular cytoplasmic pattern; topology alone does not identify which part a particular antibody recognizes (HPA tissue IHC: profile; UniProt Q03518 topology).
Cell populations represented on the section	HPA reports High staining in glandular cells of adrenal gland, appendix, breast, and duodenum; bronchial respiratory epithelial cells; colonic endothelial cells; cerebellar Purkinje cells; and bone marrow hematopoietic cells (HPA tissue IHC: High). UniProt additionally reports high expression in monocytes, dendritic cells, and T, B, and NK lymphocyte subsets (UniProt Q03518 tissue specificity).
Strength of the supplied validation	The tissue IHC profile is Approved with medium staining-to-RNA consistency, and CAB009516 has an IHC Approved designation (HPA tissue IHC: reliability; HPA antibodies: CAB009516). These designations support using the reported pattern as a comparison, while still requiring slide-level controls for a new experiment (general IHC practice).
Isoforms and processing	UniProt lists 2 isoforms, a chain spanning residues 1–748, and no annotated signal peptide, propeptide, or glycosylation sites (UniProt Q03518 isoforms and processing). Those annotations do not establish differential IHC staining, shedding, or an antibody's isoform coverage without its mapped epitope (UniProt Q03518 annotations).
IF/ICC Q&A: what localisation should an image show?	An ER pattern is supported; centriolar satellite localisation is uncertain (HPA subcellular ICC-IF: main location). HPA lists HaCaT and SK-MEL-30 ICC-IF images and rates HPA072354 ICC Supported (HPA subcellular ICC-IF: image lines; HPA antibodies: HPA072354). Interpret IF/ICC using its separate guide rather than transferring an IHC slide score to an image (general microscopy practice).

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
The positive tissue and run control are both blank.	A shared staining-run problem is plausible when independent expected signals fail together (general IHC practice).	Check reagent sequence, detection and chromogen performance, and the run control before interpreting the sample; then repeat with the catalog antibody's IHC-P instructions (general IHC practice).
The run control stains, but expected cells in the sample are blank.	The sampled area may lack the expected cells, or staining may be below detection in this preparation; a blank area alone does not establish absent TAP1 (general IHC practice).	Locate the relevant cells on the counterstained section, compare an HPA high-staining reference population, and review the antibody's IHC-P conditions (HPA tissue IHC: High; general IHC practice).
Granular signal is weak or uneven across a section.	Target-specific fixation effects are not established by the supplied assay evidence. Verify with a matched IHC source before attributing a result to fixation.	Inspect section integrity and run controls, then verify the catalog IHC-P retrieval and detection steps against its instructions (general IHC practice).
All tissue compartments show brown haze.	Nonspecific reagent background or excessive detection development can obscure the reported granular pattern (general IHC practice; HPA tissue IHC: profile).	Compare reagent controls, review blocking and washes, and adjust development using the validated IHC-P workflow (general IHC practice).
A surprising cell population stains intensely.	Cross-reactivity or endogenous detection activity is possible, but HPA's low tissue RNA specificity makes an unlisted cell type insufficient evidence of error (general IHC practice; HPA tissue IHC: RNA specificity).	Check cell identity and compartment, inspect reagent controls, and seek concordance with an independently validated antibody if the result is consequential (general IHC practice).
Nuclear or extracellular colour dominates the slide.	That distribution conflicts with TAP1's ER membrane location and HPA's granular cytoplasmic IHC profile (UniProt Q03518 subcellular location; HPA tissue IHC: profile).	Review slide morphology and controls, confirm the antibody's IHC validation, and withhold a TAP1-positive call until a compatible cytoplasmic pattern is demonstrated (HPA antibodies: CAB009516 IHC Approved; general IHC practice).

Source: UniProt Q03518 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing TAP1 staining

IHC analysis of TAP1 using anti-TAP1 antibody (PB9823). TAP1 was detected in a paraffin-embedded section of human intestinal cancer tissue. Heat mediated antigen retrieval was performed in EDTA buffer (pH 8.0, epitope retrieval solution). The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 1 μg/ml rabbit anti-TAP1 Antibody (PB9823) 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.

PB9823 · IHCIHC analysis of TAP1 using anti-TAP1 antibody (PB9823). TAP1 was detected in a paraffin-embedded section of human intestinal cancer tissue.

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000168394-TAP1/tissue/cerebral+cortex#imid_3732216

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000168394-TAP1/tissue/colon#imid_3731358

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000168394-TAP1/tissue/liver#imid_3731367

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000168394-TAP1/tissue/kidney#imid_3731352

HPA · ICC-IF HaCaTHuman Protein Atlas immunofluorescence, HaCaT, antibody HPA072354; green = TAP1, blue = nucleus, red = microtubules.

← swipe / scroll for more images →

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

Sample controls for TAP1 IHC & IF

🧪Run adrenal gland first and score glandular cells for TAP1 staining (High; HPA: adrenal gland, glandular cells). HPA detects TAP1 in all 45 scored tissues, so there is no HPA-supported negative tissue; use no-primary and isotype controls, and expect cells without specific signal on the positive slide to remain at background (HPA: no negative tissue rows; standard IHC control practice).

Positive control tissue: Adrenal gland (Glandular cells, HPA High)

Negative control tissue: None in HPA: TAP1 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show TAP1 in HaCaT, SK-MEL-30, with annotated localisation: Endoplasmic reticulum (supported), Centriolar satellite (uncertain) (HPA subcellular).

Technical controls: Include a no-primary, secondary-only control, an isotype-matched rabbit IgG control, and a matched TAP1 knockout sample as a biological negative (caption: rabbit primary; standard IHC control practice). Check endogenous peroxidase and biotin background on the adrenal gland section because the reported chromogenic detection uses a biotin-based complex with DAB (caption: biotinylated secondary, SABC and DAB; standard IHC control practice).

⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected PB9823 paraffin-section caption does not state a fixative (caption: fixative unreported). The reported IHC example uses heat retrieval in EDTA, pH 8.0, but the evidence does not establish whether retrieval is required for every specimen (caption: EDTA retrieval). Frozen-section IHC and IF cannot be ranked as easier from the supplied application evidence; for the first adrenal gland run, assess peroxidase and biotin background alongside the controls (caption: SABC and DAB; standard IHC control practice).

HPA tissue IHC evidence for TAP1

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Medium 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	High	Protein (IHC)	HPA →
Appendix	Glandular cells	High	Protein (IHC)	HPA →
Bone marrow	Hematopoietic cells	High	Protein (IHC)	HPA →
Breast	Glandular cells	High	Protein (IHC)	HPA →
Bronchus	Respiratory epithelial cells	High	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
None in HPA: TAP1 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.

Section 3

Advanced TAP1 IHC Tips

Troubleshoot TAP1 staining in paraffin sections by checking retrieval, cell identity, and the expected endoplasmic reticulum pattern before scoring chromogenic signal.

Which retrieval condition should I use when TAP1 staining is weak in paraffin sections?

Use heat-mediated retrieval in EDTA at pH 8.0 for paraffin-section TAP1 IHC (datasheet PB9823). The demonstrated section was incubated with 1 μg/ml primary antibody overnight at 4°C, so keep those conditions consistent while assessing retrieval (datasheet PB9823). Process a known positive control alongside the test sections and apply the same heating and cooling cycle to each slide (standard IHC practice). If staining remains weak, vary retrieval duration in a controlled series while checking whether tissue morphology and background deteriorate (standard IHC practice). Record the final cycle because the caption specifies the buffer and pH, but gives no retrieval duration (datasheet PB9823).

How should I troubleshoot fixation-related loss of TAP1 signal?

The selected paraffin-section example does not report its fixative, and target-specific fixation sensitivity is unknown (datasheet PB9823). Record the fixative, fixation duration, processing history, and section age for each specimen before comparing staining between cases (standard IHC practice). Run a consistently processed positive control with each batch to distinguish a specimen problem from a staining-run problem (standard IHC practice). If signal is weak, compare sections processed under documented conditions while holding EDTA retrieval at pH 8.0 and primary concentration at 1 μg/ml constant (datasheet PB9823; standard IHC practice). Do not assign a fixation effect from the observed tissue pattern alone (standard IHC practice).

What subcellular and cellular pattern should support TAP1 staining?

Expect a predominantly cytoplasmic, often granular pattern in tissue sections, consistent with TAP1 at the endoplasmic reticulum membrane (HPA tissue IHC profile; UniProt Q03518 localisation). The endoplasmic reticulum is the supported subcellular location; centriolar satellite localisation remains uncertain (HPA subcellular). TAP1 has 10 transmembrane segments and a cytoplasmic C-terminal region spanning residues 465–748, but chromogenic IHC cannot resolve which membrane face carries the antibody epitope (UniProt Q03518 topology; standard IHC practice). Assess staining within identified cell populations: monocytes, dendritic cells, and lymphocyte subsets are reported expressers (UniProt Q03518 tissue specificity). Use serial morphology or a cell-type marker when granular signal could belong to adjacent immune cells (standard IHC practice).

Could epitope location or TAP1 isoforms explain inconsistent staining?

TAP1 has 2 reported isoforms, while the supplied product caption does not identify the antibody epitope or establish recognition of both isoforms (UniProt Q03518 isoforms; datasheet PB9823). Its 10 membrane-spanning segments alternate with lumenal and cytoplasmic regions, ending in a cytoplasmic segment at residues 465–748 (UniProt Q03518 topology). Check the antibody’s documented immunogen or epitope before attributing a staining difference to isoform choice or epitope accessibility (standard IHC practice). Compare cases using the same EDTA pH 8.0 retrieval and antibody conditions, with an appropriate positive control on each run (datasheet PB9823; standard IHC practice). Report an unresolved epitope limitation when that information is unavailable (standard IHC practice).

How can I examine TAP1 by IF alongside a cell-type marker?

Treat IF/ICC as a separate assay requiring its own optimisation; the supplied PB9823 example demonstrates chromogenic paraffin-section IHC (datasheet PB9823). Multiplex TAP1 with a marker that identifies the cell population being assessed, since monocytes, dendritic cells, and lymphocyte subsets are reported TAP1 expressers (UniProt Q03518 tissue specificity; standard IF practice). Choose a spectrally separated fluorophore, considering a far-red channel where tissue autofluorescence obscures shorter wavelengths, and include single-channel controls (standard IF practice). Select permeabilisation only after establishing whether the antibody recognises a cytoplasmic or lumenal epitope within TAP1’s membrane topology (UniProt Q03518 topology; standard IF practice). Expect endoplasmic reticulum-associated signal while treating centriolar satellite localisation cautiously (HPA subcellular).

How do I reduce diffuse or misleading DAB background?

Start with the demonstrated 10% goat-serum block and 1 μg/ml primary antibody, then compare background against a slide without primary antibody (datasheet PB9823; standard IHC practice). Because the demonstrated detection uses a biotinylated secondary, streptavidin-biotin complex, and DAB, assess endogenous biotin and enzyme-related signal in suitable controls (datasheet PB9823; standard IHC practice). Apply a peroxidase block and adequate washes as routine chromogenic IHC steps, documenting any changes to the staining run (standard IHC practice). If background persists, titrate primary antibody around the demonstrated concentration without changing retrieval simultaneously (datasheet PB9823; standard IHC practice). Judge residual signal against the expected granular cytoplasmic distribution (HPA tissue IHC profile).

How should I score TAP1 staining across tissue regions? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and viable tissue region before scoring, because TAP1 expression includes professional antigen-presenting cells and lymphocyte subsets (UniProt Q03518 tissue specificity; standard IHC practice). For cellular staining, report the percentage of positive cells and an H-score from 0–300, calculated by summing each intensity grade 0–3 multiplied by its percentage (standard IHC practice). If counting stained cells, report density per mm² of analysed viable tissue and stratify by cell type (standard IHC practice). Apply one background threshold and imaging method across the comparison set (standard IHC practice). Record retrieval and staining batches, since HPA reports only medium consistency between tissue staining and RNA expression (datasheet PB9823; HPA tissue IHC reliability).

How can I distinguish genuine TAP1 staining from tissue artefact?

Favour granular cytoplasmic signal within identifiable cells, consistent with the reported tissue pattern and endoplasmic reticulum localisation of TAP1 (HPA tissue IHC profile; UniProt Q03518 localisation). Question isolated nuclear staining, strong section-edge signal, staining over necrotic areas, or DAB deposit that ignores cell boundaries (standard IHC practice). Separate signal in the cells of interest from adjacent immune cells, because TAP1 is highly expressed in monocytes, dendritic cells, and lymphocyte subsets (UniProt Q03518 tissue specificity). Use a slide without primary antibody and appropriate enzyme controls to investigate apparent endogenous detection signal (standard IHC practice). Interpret IHC as protein localisation or abundance, rather than a direct measurement of TAP1–TAP2 peptide transport activity (UniProt Q03518 function; standard IHC practice).

Boster reagents

Best TAP1 / Antigen peptide transporter 1 IHC Antibodies

The catalog includes one human-reactive anti-TAP1 antibody with an IHC figure from a paraffin-embedded human intestinal cancer section; no IF figure is supplied (catalog: PB9823; IHC image caption).

Real IHC data

Anti-TAP1 Antibody ®

Cat # PB9823

View product →

PB9823 is listed for human IHC and has an image showing staining in a paraffin-embedded human intestinal cancer section (catalog: applications and reactivity; IHC image caption). No IF validation image is supplied for PB9823 (catalog: IF images).

Which to pick: Choose PB9823 for human tissue IHC in paraffin sections; its own caption documents that preparation, while the fixative is unreported (catalog: reactivity; IHC image caption). No SKU in the payload is listed for IF/ICC, so there is no supported IF/ICC pick (catalog: applications). PB9823 is listed as human-reactive only, so there is no supported cross-species pick (catalog: reactivity).

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

References

UniProt Consortium. UniProt entry Q03518 (TAP1_HUMAN, Antigen peptide transporter 1).
Human Protein Atlas. TAP1 tissue IHC expression (reliability: Approved).
Human Protein Atlas. TAP1 subcellular location (ICC-IF): Localized to the endoplasmic reticulum and centriolar satellites..
Human Protein Atlas. TAP1 antibody validation summary (2 antibodies).
Downregulation of TAP1 and TAP2 in early stage breast cancer. PloS one 2017 — PMC5706630.
Antigen peptide transporters are upregulated in squamous cell carcinoma of the oral tongue and show sex-specific associations with survival. Oncology letters 2022 — PMC9533359.
Identification of microRNAs Targeting the Transporter Associated with Antigen Processing TAP1 in Melanoma. Journal of clinical medicine 2020 — PMC7563967.
Hedgehog signalling mediates drug resistance through targeting TAP1 in hepatocellular carcinoma. Journal of cellular and molecular medicine 2020 — PMC7171417.
PubMed PMID:2259383 — UniProt-cited evidence.
PubMed PMID:1453454 — UniProt-cited evidence.
PubMed PMID:8568858 — UniProt-cited evidence.