CDC123 / Translation initiation factor eIF2 assembly protein · IHC design guide

Design Immunohistochemistry for CDC123

This guide helps plan chromogenic CDC123 IHC on paraffin sections, with cytoplasmic staining as the expected pattern (HPA tissue IHC; UniProt). Lung alveolar cells and pancreatic exocrine glandular cells are candidate positive controls because both show high staining (HPA tissue IHC).

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

Immunohistochemistry protocol sheet for CDC123 (IHC for CDC123): expected localisation Cytoplasm (HPA tissue IHC; UniProt), antibody A08251-2, validated IHC image, and IHC protocol steps — Printable **CDC123** IHC protocol sheet — expected localisation Cytoplasm (HPA tissue IHC; UniProt), antibody A08251-2, controls and protocol steps. Open the full CDC123 IHC guide →

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CDC123 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	Cytoplasm (HPA tissue IHC; UniProt)
	Staining pattern	Broad cytoplasmic staining across tissue cell types (HPA tissue IHC)
	Antigen retrieval	EDTA pH 8.0 HIER, heat-mediated (datasheet A08251-2)
	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	Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A08251-2)
	Caveat	Staining and RNA have medium consistency (HPA tissue IHC)
	Regulation	Widely expressed; regulation unreported (UniProt)
	Isoform / epitope	No annotated isoforms; one 1–336 chain (UniProt)

Section 1

Recommended CDC123 IHC & IF Protocols

The catalog antibody’s IHC-P protocol is paired with one published CDC123 staining protocol in human fetal lung (PMC4966770).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human ovarian cancer tissue; fixative not specified (datasheet A08251-2)
Fixation	Image fixative and duration unreported (datasheet A08251-2); verify before use.
Sectioning	4–5 µm sections on charged slides (standard)
Deparaffinisation	Xylene, graded ethanol series to water (standard)
Antigen retrieval	Heat retrieval: EDTA pH 8.0 (datasheet A08251-2); 20 min, 95–100 °C (standard)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% goat serum (datasheet A08251-2)
Primary antibody	Rabbit anti-CDC123, 2-5μg/ml (datasheet A08251-2)
Primary incubation	Overnight at 4 °C (datasheet A08251-2)
Detection	Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A08251-2)
Counterstain	Hematoxylin, blue, dehydrate and mount (standard)
Expected result	CDC123-positive staining in alveolar cells of lung (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression. No signal in the no-primary control.

💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval (datasheet A08251-2); the published lung protocol used steamed citrate pH 6.0 (PMC4966770).

Section 2

What Is the Expected CDC123 Staining Pattern?

CDC123 is a cytoplasmic protein without a transmembrane segment (UniProt O75794: subcellular location and topology). In paraffin-section IHC, expect general cytoplasmic staining, especially in lung alveolar cells and pancreatic exocrine glandular cells, both scored High (HPA: tissue IHC). The HPA tissue profile is Approved, with medium consistency between antibody staining and RNA expression; use its cell-level observations as a guide, not an absolute cutoff (HPA: tissue IHC reliability).

What am I looking at on my slide?
Cytoplasmic chromogen in lung alveolar cells or pancreatic exocrine glandular cells (HPA: High in both).	This matches the strongest listed tissue IHC examples and the general cytoplasmic profile (HPA: tissue IHC). Judge signal within the specified cells, because whole-section color alone cannot identify the stained cell type (general IHC practice).
Predominantly nuclear or Golgi-like staining in a paraffin section, with little cytoplasmic signal.	Recheck compartment assignment and staining controls: tissue IHC is described as generally cytoplasmic (HPA: tissue IHC). Do not declare every noncytoplasmic signal an artefact; HPA ICC-IF also reports approved nucleoplasmic and Golgi locations (HPA: subcellular ICC-IF).
Strong staining in adipocytes, ovarian stromal cells, or smooth muscle cells (HPA: Not detected in these cells).	The result conflicts with the listed tissue IHC observations and warrants review for cross-reactivity or endogenous detection activity (HPA: tissue IHC; general IHC practice). A single discrepant section does not establish either cause or prove CDC123 is absent from every such specimen.
Diffuse color across many cell types or tissue-free areas, without a readable intracellular pattern.	Treat the pattern as background until controls and microscopic localization support a cell-specific signal (general IHC practice). HPA describes general cytoplasmic expression, but that description does not validate uniform haze or tissue-free color (HPA: tissue IHC).
No signal in lung alveolar cells or pancreatic exocrine glandular cells (HPA: High in both).	First check whether the expected cells are present and whether the detection run worked (general IHC practice). An absent signal conflicts with the HPA examples, but a failed run or unsuitable section cannot establish biological absence (HPA: tissue IHC).

💡Expected CDC123 appearanceCall positive when identifiable lung alveolar or pancreatic exocrine glandular cells show clear cytoplasmic staining, consistent with their High HPA scores; strong staining confined to listed Not detected cells or diffuse cell-free color calls for control review (HPA: tissue IHC; general IHC practice).

How each factor affects the staining
Cell-specific tissue reference (HPA: tissue IHC).	Lung alveolar and pancreatic exocrine glandular cells score High; skin keratinocytes score Medium, while adipocytes score Not detected (HPA: tissue IHC). Select and interpret controls by cell type rather than organ name alone.
Location depends on application (UniProt O75794; HPA: tissue IHC and subcellular ICC-IF).	UniProt lists cytoplasm and HPA tissue IHC describes general cytoplasmic expression. HPA ICC-IF additionally approves nucleoplasm and Golgi as main locations, with cytosol additional; those images do not set a paraffin IHC compartment rule.
Topology and annotation (UniProt O75794).	No transmembrane segment, signal peptide, propeptide, or annotated glycosylation sites are listed. This supports assessing intracellular staining, but these annotations do not establish a retrieval condition or CDC123-specific fixation sensitivity.
Validation scope (HPA: antibodies and tissue IHC reliability).	HPA037830 and HPA057540 are IHC Approved; the tissue profile has medium antibody–RNA consistency. Approved status supports comparison with the reported pattern but does not make every positive cell or compartment definitive.

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
Positive control appears blank in IHC-P (HPA: High in lung alveolar and pancreatic exocrine cells).	The expected cells may be absent, or the staining run may have failed (general IHC practice).	Confirm cell identity and section quality, then review retrieval, primary-antibody application, detection reagents, and a concurrent run control (general IHC practice). The supplied sources give no CDC123-specific retrieval setting.
Negative-control section shows diffuse chromogen.	Background may arise from endogenous detection activity or nonspecific reagent binding (general IHC practice).	Compare the appropriate no-primary and detection controls; optimize blocking and washing for the detection system (general IHC practice). Do not score diffuse color as CDC123 localization.
Unexpected strong signal appears in adipocytes or smooth muscle cells (HPA: Not detected).	Cell misidentification, cross-reactivity, or endogenous detection activity is possible (general IHC practice).	Verify morphology and compare negative controls and an independent IHC-validated antibody where available (general IHC practice; HPA: two IHC Approved antibodies). Investigate before assigning specificity.
Signal is mainly nuclear in IHC-P, with weak cytoplasm.	This differs from the general tissue IHC profile, although nucleoplasm is reported in ICC-IF (HPA: tissue IHC; subcellular ICC-IF).	Recheck compartment assignment against counterstain and controls, and compare a known-positive tissue section (general IHC practice). Record the application-specific difference rather than assuming a universal artefact.
A low-scored cell population looks unstained; for example, hippocampal neuronal cells (HPA: Low).	Weak expected staining may be difficult to distinguish from background or section variability (HPA: tissue IHC; general IHC practice).	Evaluate the run alongside a High-scored positive cell population and its controls; avoid treating a Low HPA score as an obligatory visible positive in every section (HPA: tissue IHC).
IF/ICC shows nucleoplasmic or Golgi signal that differs from the IHC-P slide.	HPA approves nucleoplasm and Golgi as main ICC-IF locations and cytosol as additional, while tissue IHC is generally cytoplasmic (HPA: subcellular ICC-IF; tissue IHC).	Interpret each application against its own HPA reference and controls (general IHC/IF practice). Use the separate IF/ICC guide for that assay; no IF/ICC protocol is specified here.

Source: UniProt O75794 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing CDC123 staining

IHC analysis of CDC123 using anti-CDC123 antibody (A08251-2). CDC123 was detected in paraffin-embedded section of human ovarian cancer tissue. Heat mediated antigen retrieval was performed in EDTA buffer (pH8.0, epitope retrieval solution). The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 2μg/ml rabbit anti-CDC123 Antibody (A08251-2) 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.

A08251-2 · IHCIHC analysis of CDC123 using anti-CDC123 antibody (A08251-2). CDC123 was detected in paraffin-embedded section of human ovarian cancer tissu

IHC analysis of CDC123 using anti-CDC123 antibody (A08251-2). CDC123 was detected in paraffin-embedded section of human placenta tissue. Heat mediated antigen retrieval was performed in EDTA buffer (pH8.0, epitope retrieval solution). The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 2μg/ml rabbit anti-CDC123 Antibody (A08251-2) 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.

A08251-2 · IHCIHC analysis of CDC123 using anti-CDC123 antibody (A08251-2). CDC123 was detected in paraffin-embedded section of human placenta tissue. Hea

IF analysis of CDC123 using anti-CDC123 antibody (A08251-2). CDC123 was detected in immunocytochemical section of A431 cells. Enzyme antigen retrieval was performed using IHC enzyme antigen retrieval reagent (AR0022) for 15 mins. The cells were blocked with 10% goat serum. And then incubated with 5μg/mL rabbit anti-CDC123 Antibody (A08251-2) overnight at 4°C. DyLight®488 Conjugated Goat Anti-Rabbit IgG (BA1127) was used as secondary antibody at 1:100 dilution and incubated for 30 minutes at 37°C. The section was counterstained with DAPI. Visualize using a fluorescence microscope and filter sets appropriate for the label used.

A08251-2 · IFIF analysis of CDC123 using anti-CDC123 antibody (A08251-2). CDC123 was detected in immunocytochemical section of A431 cells. Enzyme antigen

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000151465-CDC123/tissue/cerebral+cortex#imid_9736508

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000151465-CDC123/tissue/colon#imid_9736434

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000151465-CDC123/tissue/liver#imid_9736435

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000151465-CDC123/tissue/kidney#imid_9736428

HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA037830; green = CDC123, blue = nucleus, red = microtubules.

← swipe / scroll for more images →

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

Sample controls for CDC123 IHC & IF

🧪Run lung first: alveolar cells should stain strongly (HPA: High in alveolar cells). Use adipose tissue as the negative, with adipocytes showing no specific staining (HPA: Not detected in adipocytes); HPA does not identify a separate internal negative cell type on the lung slide, so assess other cells there against the no-primary background.

Positive control tissue: Lung (Alveolar cells, HPA High)

Negative control tissue: Adipose tissue (HPA Not detected)

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CDC123 in A-431, U-251MG, U2OS, with annotated localisation: Nucleoplasm (approved), Golgi apparatus (approved) (HPA subcellular).

Technical controls: Include no-primary (secondary-only) and matched nonimmune rabbit IgG isotype controls, plus CDC123 knockout tissue or a validated immunizing-peptide block if available (caption: rabbit primary antibody; standard IHC practice). For lung, check endogenous peroxidase and biotin background before interpreting DAB signal (caption: biotinylated secondary, streptavidin–biotin complex and DAB; standard IHC practice).

⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A08251-2 paraffin-section caption does not state the fixative (caption: fixative unreported). The caption reports heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required under other conditions (caption: EDTA pH 8.0 retrieval). Frozen-section feasibility is unreported; ICC-IF images exist for A-431, U-251MG and U2OS, but they do not establish that IF is easier than paraffin IHC (HPA: ICC-IF image cell lines; caption: paraffin-section IHC).

HPA tissue IHC evidence for CDC123

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
Lung	Alveolar cells	High	Protein (IHC)	HPA →
Pancreas	Exocrine glandular cells	High	Protein (IHC)	HPA →
Skin	Keratinocytes	Medium	Protein (IHC)	HPA →
Adrenal gland	Glandular cells	Medium	Protein (IHC)	HPA →
Appendix	Glandular cells	Medium	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
Adipose tissue	Adipocytes	Not detected	Protein (IHC)	HPA →
Oral mucosa	Squamous epithelial cells	Not detected	Protein (IHC)	HPA →
Ovary	Ovarian stroma cells	Not detected	Protein (IHC)	HPA →
Placenta	Trophoblastic cells	Not detected	Protein (IHC)	HPA →
Smooth muscle	Smooth muscle cells	Not detected	Protein (IHC)	HPA →

Section 3

Advanced CDC123 IHC Tips

Use the catalog antibody’s paraffin-section workflow as a starting point, then assess staining against CDC123’s reported expression and localisation (datasheet A08251-2; HPA tissue IHC; UniProt O75794).

What retrieval should I start with for CDC123 in paraffin sections?

Start with heat-mediated EDTA retrieval at pH 8.0 for paraffin sections (datasheet A08251-2). The selected image used that condition before 10% goat-serum blocking and 2 μg/mL primary antibody overnight at 4°C (datasheet A08251-2). If signal is weak, vary heating time on adjacent sections while keeping detection and exposure to DAB development consistent (standard IHC practice). Compare cytoplasmic staining in known positive cell populations with matched no-primary controls, rather than judging retrieval by total brown staining (HPA tissue IHC; standard IHC practice). Record the actual heating duration and cooling conditions, which the caption does not specify (datasheet A08251-2).

Could fixation explain weak CDC123 staining in my paraffin sections?

CDC123-specific sensitivity to fixation is unknown: the selected paraffin-section caption does not state a fixative or fixation duration (datasheet A08251-2). Record the fixative, time before fixation, fixation duration, and processing history for each specimen before comparing staining intensity (standard IHC practice). If material permits, stain matched sections in one run using EDTA retrieval at pH 8.0 and the same primary concentration (datasheet A08251-2; standard IHC practice). Assess tissue preservation and control staining alongside CDC123 signal, since weak staining alone cannot identify fixation as the cause (standard IHC practice). Do not infer fixation tolerance from tissue-expression patterns or protein annotations (HPA tissue IHC; UniProt O75794).

Which staining compartment should count as CDC123-positive in tissue IHC?

Prioritise a reproducible cytoplasmic pattern in intact cells: UniProt lists CDC123 as cytoplasmic, and tissue IHC reports general cytoplasmic expression (UniProt O75794; HPA tissue IHC). HPA cell-imaging data additionally report approved nucleoplasmic and Golgi localisation, with cytosolic signal, but those observations require separate validation in paraffin sections (HPA subcellular). Score nuclear or perinuclear staining separately until it agrees with appropriate controls and cell morphology (standard IHC practice). CDC123 has no annotated transmembrane segment, so a crisp cell-surface rim is unexpected from its recorded topology (UniProt O75794). Inspect a no-primary control before interpreting diffuse stain across multiple compartments (standard IHC practice).

How should epitope uncertainty affect CDC123 IHC optimisation?

The supplied record annotates 0 isoforms and one chain spanning residues 1–336; it does not identify this antibody’s epitope (UniProt O75794; datasheet A08251-2). CDC123 has an annotated phosphoserine at residue 60 and directly interacts with EIF2S3 through its C-terminus, so avoid assuming that every region is equally accessible (UniProt O75794). Start with the documented EDTA retrieval at pH 8.0, then compare controlled retrieval changes on serial sections if staining remains weak (datasheet A08251-2; standard IHC practice). Keep antibody concentration and detection conditions fixed during that comparison to isolate retrieval effects (standard IHC practice). Ask for epitope information before making region-specific biological claims (standard IHC practice).

How can I check CDC123 by IF alongside a cell-type marker?

For IF on matched material, pair CDC123 with a validated marker for the cell population being examined, such as an alveolar-cell marker where HPA reports high staining (HPA tissue IHC; standard IF practice). Choose spectrally separated fluorophores and inspect unstained tissue in each channel before selecting the CDC123 channel, because tissue autofluorescence can mimic signal (standard IF practice). Permit access to intracellular epitopes with a titrated permeabilisation step: CDC123 has no annotated transmembrane segment, while reported sites include cytoplasm, nucleoplasm, and Golgi (UniProt O75794; HPA subcellular; standard IF practice). Include single-stain and no-primary controls when assessing overlap (standard IF practice). The catalog image documents chromogenic paraffin IHC, so optimise IF conditions independently (datasheet A08251-2).

What should I change when CDC123 DAB staining is widespread?

First compare the test section with a no-primary section processed through the same secondary, streptavidin-biotin complex, and DAB steps (datasheet A08251-2; standard IHC practice). The documented workflow uses 10% goat-serum block and biotinylated goat anti-rabbit secondary for 30 minutes at 37°C (datasheet A08251-2). Check peroxidase blocking and endogenous-biotin controls when background persists, since both can contribute to signal in this detection format (standard IHC practice). Titrate primary concentration below the documented 2 μg/mL while holding development time constant, and inspect whether cytoplasmic contrast improves (datasheet A08251-2; standard IHC practice). Exclude folds, section edges, and damaged areas from this comparison (standard IHC practice).

How should I quantify CDC123 staining across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and score cytoplasmic CDC123 staining in viable tissue before comparing specimens (HPA tissue IHC; standard IHC practice). An H-score combines the percentages of cells at intensities 0–3, giving a possible range of 0–300; record the percentage positive separately (standard IHC practice). For heterogeneous samples, report positive-cell density per mm² of analysed viable tissue and the number of fields or regions sampled (standard IHC practice). Normalise comparisons to the same cell type, tissue area, staining run, and scoring threshold, with blinded review where feasible (standard IHC practice). Keep nuclear or Golgi-like signal in a separate category until validated for this assay (HPA subcellular; standard IHC practice).

How can I distinguish credible CDC123 staining from artefact?

A credible result follows cell boundaries and shows reproducible intracellular staining in intact cells, with cytoplasmic staining supported by tissue IHC and UniProt (HPA tissue IHC; UniProt O75794; standard IHC practice). HPA reports high staining in lung alveolar cells and pancreatic exocrine glandular cells, while normal ovarian stromal cells are listed as undetected (HPA tissue IHC). The catalog image shows staining in ovarian cancer tissue; that does not establish positivity in normal ovarian stroma (datasheet A08251-2; HPA tissue IHC). Discount isolated edge staining, necrotic areas, and signal persisting without primary antibody (standard IHC practice). Check endogenous peroxidase and biotin contributions before calling widespread DAB signal CDC123-positive (standard IHC practice).

Boster reagents

Best CDC123 / Translation initiation factor eIF2 assembly protein IHC Antibodies

A08251-2 has human-reactive IHC data from paraffin-embedded tissue and IF/ICC data from A431 cells (catalog: reactivity; IHC and IF image captions).

Real IHC data

Anti-CDC123 Antibody ®

Cat # A08251-2

View product →

A08251-2 was tested for IHC on paraffin-embedded human ovarian cancer, placenta, appendicitis, and bladder cancer tissue (catalog: IHC image captions). The same SKU was tested for IF/ICC in A431 cells (catalog: applications; IF image caption).

Which to pick: Choose A08251-2 for human paraffin-section IHC; its own captions document heat retrieval in EDTA at pH 8.0, while the tissue fixative is unreported (catalog: reactivity; IHC image captions). Choose A08251-2 for IF/ICC in A431 cells; its IF caption documents staining at 5 μg/mL (catalog: applications; IF image caption). No cross-species choice or clone-based comparison is supported: the only listed SKU is human-reactive, and its clone is unspecified (catalog: reactivity; clone).

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

References

UniProt Consortium. UniProt entry O75794 (CD123_HUMAN, Translation initiation factor eIF2 assembly protein).
Human Protein Atlas. CDC123 tissue IHC expression (reliability: Approved).
Human Protein Atlas. CDC123 subcellular location (ICC-IF): Mainly localized to the nucleoplasm and the Golgi apparatus. In addition localized to the cytosol..
Human Protein Atlas. CDC123 antibody validation summary (2 antibodies).
Genes associated with polymorphic variants predicting lung function are differentially expressed during human lung development. Respiratory research 2016 — PMC4966770.
PubMed PMID:8601400 — UniProt-cited evidence.
PubMed PMID:9683532 — UniProt-cited evidence.
PubMed PMID:14702039 — UniProt-cited evidence.