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BIK / Bcl-2-interacting killer · IHC design guide
Design Immunohistochemistry for BIK
Plan BIK IHC in paraffin sections using the catalog antibody PB9755 at 0.5–1 μg/ml (datasheet: PB9755), with gallbladder glandular cells as a high-staining reference (HPA tissue IHC). Compare cytoplasmic staining across sections while accounting for the low consistency between staining and RNA expression (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
BIK Immunohistochemistry Experimental Design Guide
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before staining
| Expected localisation | Cytoplasmic staining in most tissues (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic staining across tissue cell types, including glands (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet PB9755) | |
| Positive control | Gallbladder+4 more · see all | |
| Negative control | Breast+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation conditions consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Staining has low consistency with RNA expression (HPA tissue IHC) | |
| Regulation | Expression regulation is not established (UniProt) | |
| Isoform / epitope | 0 isoforms annotated; epitope sidedness is unknown (UniProt) |
Section 1
Recommended BIK IHC & IF Protocols
The catalog antibody has an IHC-P protocol (datasheet PB9755). One published BIK IHC protocol provides retrieval, primary dilution, and detection details (PMC1198222).
| Sample | Paraffin-embedded Human Thyroid Cancer tissue; fixative not specified (datasheet PB9755) |
| Fixation | Image fixative and duration unreported (datasheet PB9755); 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 PB9755) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet PB9755) |
| Primary antibody | Rabbit anti-BIK, 0.5-1μg/ml (datasheet PB9755) |
| Primary incubation | Overnight at 4 °C (datasheet PB9755) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9755) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | BIK-positive staining in glandular cells of gallbladder (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in most tissues. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated citrate pH 6 retrieval (datasheet PB9755). The published protocol uses an autoclave with citric acid at pH 6.1 (PMC1198222).
Section 2
What Is the Expected BIK Staining Pattern?
BIK is associated with endomembranes and the mitochondrial membrane, including membranes around the nuclear envelope; its transmembrane segment spans residues 136–156 (UniProt Q13323 topology and subcellular annotation). In paraffin sections, expect mainly cytoplasmic staining in the cell populations identified by HPA, especially gallbladder glandular cells and spleen red pulp cells (HPA: High; cytoplasmic expression in most tissues). Treat intensity as a reference, because HPA rates the IHC pattern Approved but reports low consistency with RNA expression (HPA: reliability).
| Cytoplasmic staining in gallbladder glandular cells or spleen red pulp cells, with tissue structure still easy to read. | This fits the strongest supplied IHC examples (HPA: High in both cell populations) and the reported cytoplasmic profile (HPA: tissue IHC). A rim near the nucleus can fit BIK's membrane annotation (UniProt Q13323 subcellular annotation); chromogenic IHC alone does not identify the particular membrane. |
| Predominantly nuclear staining, with little or no cytoplasmic signal in cells expected to stain. | A nuclear dominant pattern conflicts with the reported cytoplasmic IHC profile (HPA: tissue IHC) and BIK's endomembrane and mitochondrial membrane locations (UniProt Q13323 subcellular annotation). Review the negative control and detection background before interpreting nuclear colour as BIK. |
| Strong staining in an HPA negative cell population, such as breast adipocytes, while the expected positive cells are unclear. | Breast adipocytes are listed as Not detected (HPA: breast tissue IHC). The unexpected signal warrants checks for antibody cross reactivity and endogenous detection activity (general IHC practice). An HPA negative observation is a reference pattern, not proof that every specimen must be negative. |
| Colour covers much of the section, including spaces between cells, and obscures the expected cell pattern. | This is diffuse background rather than a readily interpretable cytoplasmic pattern (HPA: cytoplasmic expression in most tissues; general IHC practice). Compare the negative control and tissue morphology, then review blocking, antibody dilution, washing and chromogen development (general IHC practice). |
| No staining in the expected cells of a gallbladder or spleen reference section. | That conflicts with the supplied High IHC examples (HPA: gallbladder glandular cells; spleen red pulp cells). First check whether the run's controls and detection worked (general IHC practice); HPA's Approved rating and low RNA concordance do not guarantee staining in every specimen (HPA: reliability). |
💡Expected BIK appearanceCall a result consistent with the reference when cytoplasmic colour is evident in gallbladder glandular cells or spleen red pulp cells at the reported High level (HPA: tissue IHC), with a possible perinuclear membrane pattern (UniProt Q13323 subcellular annotation); predominantly nuclear colour or staining that obscures cell boundaries should prompt a background check (general IHC practice).
| Membrane location and topology | BIK has one transmembrane segment at residues 136–156 (UniProt Q13323 topology). Its reported endomembrane and mitochondrial membrane locations support cytoplasmic or perinuclear interpretation (UniProt Q13323 subcellular annotation), but routine chromogenic IHC cannot resolve those membranes by itself (general IHC practice). |
| Tissue and cell selection | Gallbladder glandular cells and spleen red pulp cells offer High reference staining; appendix and colon glandular cells are Medium examples (HPA: tissue IHC). Choose the exact cell population when judging a section, since a tissue level label does not make every cell positive (HPA: cell specific tissue IHC). |
| Strength of antibody evidence | HPA lists antibody HPA051360 as Approved for IHC, with low consistency between staining and RNA data (HPA: antibody validation; reliability description). Use its image pattern as a qualified reference and evaluate controls alongside it (general IHC practice); Approved should not be presented as Enhanced. |
| RNA versus protein observations | RNA is tissue enhanced in salivary gland, while the supplied High protein staining examples are gallbladder and spleen (HPA: RNA specificity; tissue IHC). Do not infer a salivary gland IHC intensity from that RNA label, especially given the stated low staining to RNA consistency (HPA: reliability description). |
| Processing annotations | UniProt lists a single chain spanning residues 1–160, with no signal peptide, propeptide or annotated glycosylation sites (UniProt Q13323 processing and glycosylation). These annotations give no basis here for a cleavage or glycosylation specific staining pattern; the antibody epitope is not supplied. |
| IF/ICC: is the same pattern established? | HPA summarizes the subcellular location as Membrane but provides no ICC IF image cell lines or main location in this payload (HPA: subcellular summary). UniProt supports membrane association (UniProt Q13323 subcellular annotation); this record does not establish an IF cell model or a specific fluorescent pattern. |
| Situation | Likely cause | Next action |
|---|---|---|
| Gallbladder glandular cells show no colour. | The section conflicts with a High reference observation (HPA: gallbladder tissue IHC); the cause is undetermined from the image alone. | Check the run's positive and negative controls, antibody application and detection sequence (general IHC practice). If controls pass, review the specimen and compare the same cell population with the HPA reference (HPA: gallbladder glandular cells). |
| The section is uniformly brown or cell borders are hard to distinguish. | Diffuse colour can arise from background in the detection workflow (general IHC practice); it does not resemble HPA's cell based cytoplasmic profile (HPA: tissue IHC). | Inspect the negative control; then review blocking, wash steps, antibody dilution and chromogen development (general IHC practice). Score BIK only where cell associated signal can be separated from background. |
| Nuclei are the dominant stained compartment. | This conflicts with the cytoplasmic IHC profile (HPA: tissue IHC) and the annotated membrane locations (UniProt Q13323 subcellular annotation). | Compare nuclear counterstain with chromogen and inspect the negative control (general IHC practice). Reassess the staining call if nuclear colour persists without the expected cytoplasmic pattern. |
| Breast adipocytes stain as strongly as the intended positive cells. | HPA reports breast adipocytes as Not detected (HPA: breast tissue IHC); cross reactivity or endogenous detection activity are possibilities, not diagnoses (general IHC practice). | Check negative controls and any appropriate endogenous activity block for the chosen detection chemistry (general IHC practice). Compare cell identity and staining distribution before assigning BIK positivity. |
| A low or negative reference cell population is used to judge assay failure. | HPA lists lung macrophages as Low and liver cholangiocytes as Not detected (HPA: tissue IHC); weak or absent colour there may match the reference. | Judge run performance using an appropriate positive population, such as gallbladder glandular cells or spleen red pulp cells (HPA: High), together with the run controls (general IHC practice). |
| A salivary gland RNA result is used to demand strong IHC staining. | Salivary gland is tissue enhanced for RNA, while HPA states low consistency between antibody staining and RNA expression (HPA: RNA specificity; reliability description). | Score the observed IHC cell pattern and controls on their own terms (general IHC practice). Use the supplied gallbladder or spleen High protein examples as staining references (HPA: tissue IHC). |
Experiment evidence
IHC & IF images showing BIK staining
PB9755 · IHCIHC analysis of Bik using anti-Bik antibody (PB9755). Bik was detected in paraffin-embedded section of Human Thyroid Cancer Tissue. Heat med
PB9755 · IHCIHC analysis of Bik using anti-Bik antibody (PB9755). Bik was detected in paraffin-embedded section of Mouse Spleen Tissue. Heat mediated an
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000100290-BIK/tissue/cerebral+cortex#imid_16326914
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000100290-BIK/tissue/colon#imid_16314049
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000100290-BIK/tissue/liver#imid_16314058
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000100290-BIK/tissue/kidney#imid_16314059
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for BIK IHC & IF
🧪Run gallbladder first; its glandular cells should stain (HPA: High in gallbladder glandular cells). Use breast adipocytes as the negative tissue compartment (HPA: Not detected in breast adipocytes); compare nonglandular cells on the gallbladder slide with the glandular cells, without presuming those other cells lack BIK (HPA: gallbladder row reports glandular cells only).
Positive control tissue: Gallbladder (Glandular cells, HPA High)
Negative control tissue: Breast (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for BIK; derive a cell-line control from the positive tissue's cell type (Glandular cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control and concentration-matched nonimmune rabbit IgG matched to the primary’s clonality where applicable (PB9755 tissue-IHC caption: rabbit primary); confirm specificity with BIK-knockout material processed alongside the test section (standard IHC practice). For gallbladder, quench endogenous peroxidase and check for endogenous biotin before interpreting DAB staining (PB9755 tissue-IHC caption: SABC/DAB detection; standard IHC practice).
⚠️Feasibility: A BIK-specific fixation window or fixation effect is unreported, and the selected paraffin-section caption does not state the fixative (PB9755 tissue-IHC caption). Start with the reported 20-minute citrate pH 6 heat retrieval, while treating retrieval dependence as unestablished; the supplied evidence does not show that frozen sections or IF/ICC are easier (PB9755 tissue-IHC caption; HPA subcellular: no ICC-IF image cell lines). In gallbladder, distinguish bile pigment or luminal debris from brown DAB signal using the no-primary slide (standard IHC practice).
HPA tissue IHC evidence for BIK
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low 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 |
|---|---|---|---|---|
| Gallbladder | Glandular cells | High | Protein (IHC) | HPA → |
| Spleen | Cells in red pulp | High | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Medium | Protein (IHC) | HPA → |
| Bronchus | Ciliated cells (tip of cilia) | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Cerebral cortex | Endothelial cells | Not detected | Protein (IHC) | HPA → |
| Cervix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Hippocampus | Glial cells | Not detected | Protein (IHC) | HPA → |
| Liver | Cholangiocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced BIK IHC Tips
Troubleshoot BIK staining in paraffin sections by checking retrieval, cellular distribution, controls, and scoring against the available tissue evidence.
How should I retrieve BIK antigen when staining paraffin sections?
Start with heat-mediated retrieval in citrate buffer at pH 6 for 20 minutes (datasheet PB9755). That condition accompanies BIK staining in a paraffin section of human thyroid cancer; the caption does not report its fixative (datasheet PB9755). If staining is weak, compare a longer or shorter heating interval on adjacent sections while keeping the buffer and detection steps constant (standard IHC practice). Include a known staining control, such as gallbladder glandular cells, and examine both signal and tissue preservation before accepting a change (HPA: High in gallbladder glandular cells; standard IHC practice).
Could fixation explain weak or uneven BIK staining?
BIK-specific sensitivity to fixation is unknown from the supplied evidence; the catalog image identifies a paraffin section but gives no fixative (datasheet PB9755). Record the actual fixative and fixation duration for each specimen, then compare similarly processed sections before attributing a weak result to BIK biology (standard IHC practice). Check whether staining loss tracks thick tissue regions or poorly preserved morphology, and assess an independently validated control on the same preparation (standard IHC practice). Avoid inferring fixation tolerance from cytoplasmic tissue staining or membrane topology, which establish neither fixation conditions nor epitope survival (HPA: cytoplasmic expression in most tissues; UniProt Q13323 topology).
Where should convincing BIK staining appear in an IHC section?
Evaluate BIK chiefly as cytoplasmic or membrane-associated staining: tissue IHC reports cytoplasmic expression, while UniProt places it around the nuclear envelope and cytoplasmic membranes (HPA: tissue profile; UniProt Q13323 subcellular location). A transmembrane segment spans residues 136–156, so a crisp nuclear-only pattern warrants scrutiny rather than automatic acceptance (UniProt Q13323 topology; standard IHC practice). Compare the suspected signal with compartment boundaries and a nuclear counterstain on the same section (standard IHC practice). Interpret staining within identified cells: gallbladder glandular cells are reported High, whereas breast adipocytes are Not detected (HPA: gallbladder and breast tissue IHC).
How do BIK topology and epitope location affect staining?
BIK is a 160-amino-acid protein with one annotated chain, no listed isoforms, and a transmembrane segment at residues 136–156 (UniProt Q13323 sequence and topology). Determine the antibody's immunogen or mapped epitope from its documentation before interpreting a failed stain as absence of BIK (standard IHC practice). An epitope beside or beyond the membrane anchor may differ in accessibility after section processing; its location is not established by the supplied caption (UniProt Q13323 topology; datasheet PB9755). Compare retrieval conditions on matched sections and require an appropriate positive control before drawing conclusions about epitope masking (standard IHC practice).
How can IF help assess the cellular source of BIK signal?
For a separate IF/ICC assessment, multiplex BIK with a glandular cell marker to test whether signal lies in the cell type reported as High in gallbladder tissue IHC (HPA: gallbladder glandular cells; standard IF practice). Select fluorophores after inspecting unstained tissue for autofluorescence, and favor a spectrally separated, longer-wavelength channel when background is strong (standard IF practice). Because BIK includes a membrane anchor at residues 136–156, choose permeabilisation according to whether the antibody epitope faces the accessible or intracellular side; its side is unspecified here (UniProt Q13323 topology; standard IF practice). Include single-channel and secondary-only controls when assessing overlap (standard IF practice).
What should I check when DAB background obscures BIK staining?
First inspect a no-primary section to separate primary-antibody staining from detection-system or tissue background (standard IHC practice). The catalog image used 10% goat serum blocking, 1 µg/mL primary antibody overnight at 4°C, and a biotin-based DAB detection system (datasheet PB9755). For diffuse background, reassess blocking, washing, primary concentration, and incubation time one variable at a time (standard IHC practice). Include a peroxidase block before DAB development, and consider endogenous biotin when troubleshooting a biotin-based system; these are general workflow checks, not demonstrated BIK-specific requirements (standard IHC practice; datasheet PB9755).
How should I score BIK staining across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and tissue compartment before scoring, then record the percentage of positive cells and staining intensity on a consistent 0–3 scale (standard IHC practice). An H-score can combine those observations by summing each intensity score multiplied by its corresponding positive-cell percentage (standard IHC practice). For spatial comparisons, report positive-cell density per mm² of viable, evaluated tissue and exclude artefactual or necrotic regions (standard IHC practice). Normalise comparisons to the same cell type, section area, imaging settings, and staining batch; the HPA profile shows that expression differs among cell populations (HPA: tissue IHC profile; standard IHC practice).
When is an apparent BIK-positive cell likely to be an artefact?
Favor reproducible cytoplasmic or membrane-associated signal in identifiable cells over isolated nuclear-only staining, which conflicts with the reported distribution (HPA: tissue profile; UniProt Q13323 subcellular location). Compare candidate positives with a no-primary control and with reported contrasts such as High gallbladder glandular cells and Not detected breast adipocytes (HPA: gallbladder and breast tissue IHC; standard IHC practice). Distrust staining confined to section edges, necrotic areas, or sites showing endogenous enzyme activity in controls (standard IHC practice). HPA rates its tissue antibody Approved but notes low consistency with RNA expression, so staining alone should not establish BIK abundance or apoptotic activity (HPA: reliability description; UniProt Q13323 function).
Boster reagents
Best BIK / Bcl-2-interacting killer IHC Antibodies
PB9755 has IHC images from paraffin sections of human thyroid cancer, mouse spleen and rat spleen (catalog image captions); ICC is listed, but no IF image is supplied (catalog applications; IF image list).
Real IHC data
Anti-Bik Antibody ®
Cat # PB9755
PB9755 is the sole card and has paraffin-section IHC images from human thyroid cancer, mouse spleen and rat spleen (catalog image captions). It is listed for IHC and ICC in human, mouse and rat (catalog applications and reactivity).
Which to pick: Choose PB9755 for paraffin-section IHC: its own caption documents citrate retrieval at pH 6 for 20 minutes, followed by 1 μg/ml primary antibody and chromogenic detection (PB9755 IHC image caption). For IF/ICC, PB9755 lists ICC and 0.5–1 μg/ml as the IF dilution, but supplies no IF image (catalog applications, IF dilution and IF image list). It is the cross-species choice because human, mouse and rat are listed and pictured for IHC; the caption does not report the fixative (catalog reactivity; PB9755 IHC image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q13323 (BIK_HUMAN, Bcl-2-interacting killer).
- Human Protein Atlas. BIK tissue IHC expression (reliability: Approved).
- Human Protein Atlas. BIK subcellular location (ICC-IF): Membrane.
- Human Protein Atlas. BIK antibody validation summary (1 antibodies).
- A molecular analysis by gene expression profiling reveals Bik/NBK overexpression in sporadic breast tumor samples of Mexican females. BMC cancer 2005 — PMC1198222.
- Induced autoimmunity against gonadal proteins affects gonadal development in juvenile zebrafish. PloS one 2014 — PMC4250200.
- BIK drives an aggressive breast cancer phenotype through sublethal apoptosis and predicts poor prognosis of ER-positive breast cancer. Cell death & disease 2020 — PMC7289861.
- Interrogation of gender disparity uncovers androgen receptor as the transcriptional activator for oncogenic miR-125b in gastric cancer. Cell death & disease 2021 — PMC8096848.
- PubMed PMID:7478623 — UniProt-cited evidence.
- PubMed PMID:8816500 — UniProt-cited evidence.
- PubMed PMID:10500065 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for BIK (Bcl-2-interacting killer). Expected localisation Cytoplasmic staining in most tissues (HPA tissue IHC). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet PB9755). Validated IHC antibody: PB9755 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Gallbladder (Glandular cells); negative Breast. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded Human Thyroid Cancer tissue; fixative not specified (datasheet PB9755); 2. Fixation: Image fixative and duration unreported (datasheet PB9755); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: Citrate pH 6 , 20 min (datasheet PB9755); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet PB9755); 8. Primary antibody: Rabbit anti-BIK, 0.5-1μg/ml (datasheet PB9755); 9. Primary incubation: Overnight at 4 °C (datasheet PB9755). Watch for: Fixation: Keep fixation conditions consistent across sections. (standard IHC practice; not target-specific); Caveat: Staining has low consistency with RNA expression (HPA tissue IHC); Isoform / epitope: 0 isoforms annotated; epitope sidedness is unknown (UniProt); Regulation: Expression regulation is not established (UniProt). Evidence: UniProt Q13323, HPA tissue IHC · Approved, HPA ICC-IF · Membrane, Datasheet PB9755, PMC1198222. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/BIK/immunohistochemistry-ihc-guide.