ORM1 / Alpha-1-acid glycoprotein 1 · IHC design guide

Design Immunohistochemistry for ORM1

Plan chromogenic IHC for ORM1 in paraffin sections using plasma positivity as the observed tissue pattern (HPA tissue IHC). The guide covers fixation, retrieval, antibody dilution and interpretation of a secreted protein (UniProt; datasheet PB9956).

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

Immunohistochemistry protocol sheet for ORM1 (IHC for ORM1): expected localisation Secreted (UniProt); plasma staining observed (HPA tissue IHC), antibody PB9956, validated IHC image, and IHC protocol steps — Printable **ORM1** IHC protocol sheet — expected localisation Secreted (UniProt); plasma staining observed (HPA tissue IHC), antibody PB9956, controls and protocol steps. Open the full ORM1 IHC guide →

Navigate to: Protocols Staining pattern Controls Antibodies

ORM1 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	Secreted (UniProt); plasma staining observed (HPA tissue IHC)
	Staining pattern	Plasma positivity; cellular pattern unresolved (HPA tissue IHC)
	Antigen retrieval	EDTA pH 8.0 HIER, heat-mediated (datasheet PB9956)
	Positive control ⓘ	Testis
	Negative control ⓘ	Adipose tissue+4 more · see all

Important caveats

Reasons your staining may differ from the expected pattern.

	Fixation	Keep fixation consistent across sections. (standard IHC practice; not target-specific)
	Caveat	Secreted protein may stain away from its site of synthesis (HPA tissue IHC)
	Regulation	Associated with the acute-phase response (UniProt)
	Isoform / epitope	No isoforms listed; mature chain spans 19–201 (UniProt)

Section 1

Recommended ORM1 IHC & IF Protocols

Compare the catalog antibody’s IHC-P protocol with 4 published ORM1 IHC protocols (datasheet: PB9956; PMC8491347; PMC4916783; PMC9589312; PMC9467997).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human intestinal cancer tissue; fixative not specified (datasheet PB9956)
Fixation	Image fixative and duration unreported (datasheet PB9956); 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 PB9956); 20 min, 95–100 °C (standard)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% goat serum (datasheet PB9956)
Primary antibody	Rabbit anti-ORM1, 0.5-1μg/ml (datasheet PB9956)
Primary incubation	Overnight at 4 °C (datasheet PB9956)
Detection	Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9956)
Counterstain	Hematoxylin, blue, dehydrate and mount (standard)
Expected result	ORM1-positive staining in elongated or late spermatids of testis (HPA tissue IHC: High). HPA tissue profile: Positivity in plasma. No signal in the no-primary control.

💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 for the catalog antibody (datasheet: PB9956). Citrate at pH 6.2 is a published alternative (PMC4916783).

Section 2

What Is the Expected ORM1 Staining Pattern?

ORM1 is secreted, has no transmembrane segment, and is expressed by the liver before entering plasma (UniProt P02763). In tissue IHC, expect plasma-associated positivity and high staining in elongated or late spermatids; do not infer that every liver cell must stain (HPA tissue IHC). HPA rates its tissue profile Approved but cautions that the antibodies can target proteins from more than one gene (HPA tissue IHC).

What am I looking at on my slide?
Plasma-associated staining, with high signal in elongated or late spermatids (HPA tissue IHC).	This matches the reported tissue pattern (HPA tissue IHC). Because ORM1 is secreted into plasma, extracellular signal need not identify the cell that produced it (UniProt P02763).
A dominant nuclear, membrane-rim, or other unexpected intracellular pattern.	That pattern is unsupported by ORM1's secreted, non-transmembrane annotation (UniProt P02763). Review morphology and controls before assigning it to ORM1; HPA vesicle and Golgi observations come from ICC-IF, not tissue IHC (HPA subcellular).
Strong staining confined to a cell population listed as not detected, such as adipocytes or respiratory epithelial cells (HPA tissue IHC).	Consider cross-reactivity or endogenous detection activity (general IHC practice). Check whether the signal instead follows plasma or extracellular material, since secreted ORM1 can appear away from its producing cells (UniProt P02763).
Broad, diffuse color across tissue and background, without a discernible plasma-associated or spermatid pattern.	This is difficult to interpret as specific ORM1 staining against the reported pattern (HPA tissue IHC). Background may arise from detection chemistry or nonspecific binding; inspect matched reagent controls (general IHC practice).
No staining in an adequately represented testis section containing elongated or late spermatids.	The reported high signal makes this a useful investigation trigger, not proof that ORM1 is absent (HPA tissue IHC). Check cell-stage representation and run conditions (general IHC practice).

💡Expected ORM1 appearanceCall positive when plasma-associated staining and high elongated or late spermatid staining fit the section (HPA tissue IHC); isolated dominant nuclear or membrane-rim staining is unsupported by ORM1 topology (UniProt P02763).

How each factor affects the staining
Secretion and tissue origin (UniProt P02763).	Liver expression and secretion into plasma mean protein location can differ from RNA location (UniProt P02763; HPA tissue IHC). Interpret extracellular staining by location, without calling nearby cells producers.
Reported tissue contrast (HPA tissue IHC).	Testis elongated or late spermatids are reported High; selected adipocytes, glandular cells, respiratory epithelial cells, and other listed populations are Not detected (HPA tissue IHC). These are cell-specific comparisons, not whole-organ negatives.
Antibody scope and validation (HPA tissue IHC; HPA antibodies).	The tissue profile is Approved, while HPA cautions that antibodies target proteins from more than one gene (HPA tissue IHC). Listed IHC antibodies are Approved, so a matching stain still requires specificity-aware interpretation (HPA antibodies; HPA tissue IHC).
Processing and glycosylation (UniProt P02763).	ORM1 has a signal peptide at residues 1–18, a chain at 19–201, and five annotated glycosylation sites (UniProt P02763). These features describe the protein; the supplied sources do not establish an antigen-retrieval or fixation effect.
ICC-IF compartment evidence (HPA subcellular).	HPA reports mainly vesicles and additional Golgi localization in ICC-IF, with a multiple-gene antibody caution (HPA subcellular). Use this as qualified IF context; it does not replace the plasma-associated tissue IHC expectation (HPA tissue IHC).
Detection chemistry (general IHC practice).	Endogenous enzyme activity or nonspecific detection can add chromogenic signal (general IHC practice). Reagent controls help separate this from the reported ORM1 tissue pattern (HPA tissue IHC); no ORM1-specific susceptibility is established here.

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
Expected testis signal is absent (HPA tissue IHC).	Elongated or late spermatids may be missing from the section, or the staining run may have failed (general IHC practice).	Confirm those cells are present, inspect the positive control, and review antibody and detection steps before interpreting absence (general IHC practice).
Strong signal appears in a listed Not detected cell population (HPA tissue IHC).	Cross-reactivity, endogenous detection activity, or adjacent plasma-associated staining may explain it (general IHC practice; UniProt P02763).	Compare cell boundaries with extracellular material and review reagent controls; report unresolved signal as nonspecific or uncertain (general IHC practice).
A nuclear or membrane-rim pattern dominates.	That compartment assignment conflicts with secreted, non-transmembrane ORM1 topology (UniProt P02763).	Recheck morphology, antibody specificity, and detection controls before calling the stain ORM1-positive (general IHC practice; HPA tissue IHC).
Color spreads across the section and obscures the expected pattern.	Nonspecific binding or detection background can obscure localization (general IHC practice).	Review blocking, washes, antibody concentration, and detection controls; compare with plasma-associated and spermatid staining (general IHC practice; HPA tissue IHC).
Plasma-associated staining is mistaken for expression by adjacent cells.	ORM1 is produced by the liver and secreted into plasma; tissue protein and RNA locations can differ (UniProt P02763; HPA tissue IHC).	Score extracellular signal separately from cell-associated signal, and avoid assigning a producer cell from proximity alone (UniProt P02763).
Can IF/ICC use the same compartment call as tissue IHC?	HPA reports vesicles and additional Golgi localization in ICC-IF, while tissue IHC reports plasma positivity (HPA subcellular; HPA tissue IHC).	Interpret IF/ICC on its own guide page using its qualified compartment evidence; do not treat the ICC-IF pattern as a tissue IHC control (HPA subcellular; HPA tissue IHC).

Source: UniProt P02763 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing ORM1 staining

IHC analysis of ORM1 using anti-ORM1 antibody (PB9956). ORM1 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-ORM1 Antibody (PB9956) 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.

PB9956 · IHCIHC analysis of ORM1 using anti-ORM1 antibody (PB9956). ORM1 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/ENSG00000229314-ORM1/tissue/cerebral+cortex#imid_12602353

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000229314-ORM1/tissue/colon#imid_12602287

HPA · RectumHuman Protein Atlas IHC, Rectum. Source: https://www.proteinatlas.org/ENSG00000229314-ORM1/tissue/rectum#imid_12602255

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000229314-ORM1/tissue/liver#imid_2069119

HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA047725; green = ORM1, blue = nucleus, red = microtubules.

← swipe / scroll for more images →

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

Sample controls for ORM1 IHC & IF

🧪Run testis first and look for staining in elongated or late spermatids (HPA: High in elongated or late spermatids). Use adipose tissue as a negative tissue (HPA: Not detected in adipocytes); cells outside the stained spermatid population on the positive slide should show only background signal (standard IHC control practice).

Positive control tissue: Testis (Elongated or late spermatids, HPA High)

Negative control tissue: Adipose tissue (HPA Not detected)

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show ORM1 in A-431, Hep-G2, U2OS, with annotated localisation: Vesicles (approved) (HPA subcellular).

Technical controls: Include a no-primary secondary-only control, a rabbit IgG control matched to the primary antibody’s format and concentration, and ORM1 knockout material or an immunizing-peptide block if available (caption: rabbit primary; standard IHC control practice). For the testis slide, block endogenous peroxidase and check endogenous biotin background before interpreting DAB staining (caption: biotin-based detection with DAB; standard IHC practice).

⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected PB9956 caption does not state a fixative (selected PB9956 caption). Heat retrieval in EDTA at pH 8.0 was used for a paraffin-section example, but the evidence does not establish that retrieval is required; frozen-section use and whether IF is easier are unreported (selected PB9956 caption; HPA: ICC-IF images in A-431, Hep-G2 and U2OS). Because ORM1 is secreted into plasma, vascular or extracellular staining in testis needs cautious interpretation against the spermatid staining pattern (UniProt P02763: secreted and expressed by the liver; HPA: High in elongated or late spermatids).

HPA tissue IHC evidence for ORM1

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Caution, targets protein from more than one gene. Secreted protein, tissue location of RNA and protein is expected to differ.). 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
Testis	Elongated or late spermatids	High	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 →
Bone marrow	Hematopoietic cells	Not detected	Protein (IHC)	HPA →
Breast	Adipocytes	Not detected	Protein (IHC)	HPA →

Section 3

Advanced ORM1 IHC Tips

Troubleshoot ORM1 staining in paraffin sections using the PB9956 tissue-IHC conditions, while accounting for secretion, glycosylation and plasma-associated signal.

What retrieval should I try when ORM1 staining is weak in paraffin sections?

Start with heat-mediated retrieval in EDTA, pH 8.0 (datasheet PB9956). The PB9956 tissue image used that retrieval before staining a paraffin section with 1 μg/ml primary antibody overnight at 4°C (datasheet PB9956). If staining remains weak, check section adhesion, heating consistency and reagent performance, then compare retrieval durations on adjacent sections while holding detection conditions constant (standard IHC practice). Record both tissue signal and background at each duration, because a brighter plasma-rich area alone does not establish improved cellular detection: ORM1 is secreted into plasma (UniProt P02763; HPA: positivity in plasma).

How should I troubleshoot fixation-related differences in ORM1 IHC staining?

The PB9956 caption identifies a paraffin-embedded section but does not state its fixative, so target-specific fixation sensitivity is unknown (datasheet PB9956). Record the fixative, fixation duration and tissue thickness for each specimen, and compare sections processed under matched conditions before attributing a weak result to ORM1 biology (standard IHC practice). Keep retrieval at EDTA, pH 8.0 and the primary incubation at 1 μg/ml overnight at 4°C while evaluating processing differences (datasheet PB9956). Inspect morphology and include a consistently processed reference section in each run; HPA staining patterns cannot establish how this antibody responds to fixation (standard IHC practice; HPA: tissue-IHC profile).

Should ORM1 appear inside cells or in extracellular material?

Interpret chromogenic signal in light of ORM1 secretion: liver expression and release into plasma are reported, and the protein has no transmembrane segment (UniProt P02763). HPA reports plasma positivity and cautions that tissue RNA and protein locations can differ for a secreted protein (HPA: tissue-IHC profile). Accordingly, evaluate intracellular staining separately from vessel contents and diffuse extracellular staining, rather than assigning every DAB-positive area to local synthesis (standard IHC practice; UniProt P02763: secreted). If a cellular pattern is the main finding, compare it with morphology and an appropriate control section; HPA IF reports vesicular and Golgi localisation but cautions that its antibodies target proteins from multiple genes (HPA: subcellular profile).

Could ORM1 processing or glycosylation change the staining pattern?

ORM1 has a cleaved signal peptide at residues 1–18, a mature chain at 19–201, and five annotated glycosylation sites (UniProt P02763). Its mature N-terminal residue is also modified, while no isoforms or domains are annotated in the supplied record (UniProt P02763). Without a mapped PB9956 epitope, these annotations cannot establish whether processing or glycosylation changes antibody binding in paraffin sections (UniProt P02763; datasheet PB9956: epitope not specified). When results differ between specimens, first compare retrieval, incubation and detection under matched conditions; use an independently validated ORM1 reagent if the interpretation depends on a particular epitope (standard IHC practice).

How should I adapt the ORM1 interpretation when planning multiplex IF?

Treat IF as a separately optimised application; the PB9956 caption documents chromogenic staining of a paraffin section, with its fixative unreported (datasheet PB9956). For multiplex IF, pair ORM1 with a marker for the cell population being tested, and distinguish cellular signal from surrounding plasma-associated signal (standard IF practice; HPA: positivity in plasma). Choose spectrally separated fluorophores and check an unstained section for tissue autofluorescence before assigning a dim ORM1 signal (standard IF practice). Select permeabilisation according to the mapped epitope and whether intracellular access is required; ORM1 lacks a transmembrane segment, while HPA reports vesicular and Golgi IF signal with a multiple-gene antibody caution (UniProt P02763; HPA: subcellular profile).

What causes widespread DAB signal that obscures ORM1-positive structures?

First separate plausible ORM1-associated plasma staining from nonspecific deposition: ORM1 is secreted, and HPA reports positivity in plasma (UniProt P02763; HPA: tissue-IHC profile). The PB9956 image used 10% goat serum blocking, 1 μg/ml primary antibody, a biotinylated secondary, an avidin-biotin complex and DAB (datasheet PB9956). Compare a no-primary control, apply a peroxidase block, and inspect tissue edges and damaged regions before changing antibody concentration (standard chromogenic IHC practice). If diffuse staining persists, assess secondary and avidin-biotin detection controls, then titrate the primary while keeping retrieval at EDTA, pH 8.0 and documenting any loss of interpretable signal (standard IHC practice; datasheet PB9956).

How should I score ORM1 when plasma staining overlaps cellular staining? ⚠ ANSWER MARKED FOR VERIFICATION

Define compartments before scoring: ORM1 is secreted into plasma, so extracellular staining and staining assigned to cells answer different questions (UniProt P02763; HPA: positivity in plasma). For a cellular endpoint, record the percentage of positive cells and intensity, or calculate an H-score from prespecified intensity categories (standard IHC practice). For a spatial endpoint, measure DAB-positive area per mm² of evaluable tissue and report vessel-associated signal separately (standard IHC practice; HPA: positivity in plasma). Normalise comparisons to the same tissue compartment, evaluable area and staining batch, and exclude folds, necrosis and edges using rules set before scoring (standard IHC practice).

How can I distinguish convincing ORM1 staining from an artefact?

A convincing result has reproducible staining in an anatomically defined compartment, with appropriate control behaviour and intact tissue morphology (standard IHC practice). ORM1 is secreted into plasma, so vessel-associated or extracellular DAB can be plausible without proving expression by nearby cells (UniProt P02763; HPA: positivity in plasma). Investigate an isolated cellular claim when staining concentrates at section edges, necrotic areas or sites of endogenous enzyme activity, especially if the no-primary control is positive (standard chromogenic IHC practice). HPA reports high staining in elongated or late spermatids but cautions that its tissue antibodies can detect proteins from multiple genes; use that pattern as context, not ORM1-specific confirmation (HPA: tissue-IHC profile).

Boster reagents

Best ORM1 / Alpha-1-acid glycoprotein 1 IHC Antibodies

PB9956 has real ORM1 IHC data from a human paraffin-embedded intestinal cancer section (catalog IHC caption). No IF data is supplied (catalog IF images; catalog IF dilution).

Real IHC data

Anti-Alpha 1 Acid Glycoprotein/ORM1 Antibody ®

Cat # PB9956

View product →

PB9956 is the sole card and shows IHC staining of a human paraffin-embedded intestinal cancer section (catalog cards; PB9956 IHC caption). It lists Human, Mouse and Rat reactivity and IHC among its applications (catalog reactivity; catalog applications).

Which to pick: Choose PB9956 for human paraffin-section chromogenic IHC: its figure documents EDTA retrieval at pH 8.0, 1 μg/ml primary antibody and DAB detection (PB9956 IHC caption). No IF/ICC pick is supported because PB9956 has no listed IF application, image or dilution; its clonality is unreported (catalog applications; catalog IF data; catalog clone). PB9956 lists Human, Mouse and Rat reactivity, but its supplied IHC figure covers human tissue only, and the fixative is unreported (catalog reactivity; PB9956 IHC caption).

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

References

UniProt Consortium. UniProt entry P02763 (A1AG1_HUMAN, Alpha-1-acid glycoprotein 1).
Human Protein Atlas. ORM1 tissue IHC expression (reliability: Approved).
Human Protein Atlas. ORM1 subcellular location (ICC-IF): Mainly localized to vesicles. In addition localized to the Golgi apparatus. Caution: Based on antibodies targeting proteins from multiple genes..
Human Protein Atlas. ORM1 antibody validation summary (4 antibodies).
Comparison of orosomucoid-1 immunoexpression and angiogenesis between oral squamous cell carcinoma cases with different histological grades. Journal of oral and maxillofacial pathology : JOMFP 2021 — PMC8491347.
Orosomucoid-1 Expression in Ameloblastoma Variants. International journal of molecular and cellular medicine 2016 — PMC4916783.
ORM 1 as a biomarker of increased vascular invasion and decreased sorafenib sensitivity in hepatocellular carcinoma. Bosnian journal of basic medical sciences 2022 — PMC9589312.
Salivary orosomucoid 1 as a biomarker of hepatitis B associated hepatocellular carcinoma. Scientific reports 2022 — PMC9467997.
PubMed PMID:2409529 — UniProt-cited evidence.
PubMed PMID:3770479 — UniProt-cited evidence.
PubMed PMID:2822385 — UniProt-cited evidence.