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P·01 Products / Immune profiling

TC8 — anti-CD8 for tumour-infiltrating lymphocytes in brightfield and multiplex IHC.

Clone TC8 · Cat. no. DIA-TC8 · T-cell co-receptor CD8, membranous staining pattern

Scientific USP

5 clone-specific peer-reviewed publications

2,652Evaluable tumors
84Tumor entities
3,988Tumors · CD8/Ki67 multiplex · digital quantification
  • Brightfield + multiplex IHC
  • Membranous CD8 · human FFPE

Publications — cohort sizes as reported in the respective clone-specific studies.

Mouse monoclonal antibody for studying CD8-positive lymphocytes in human formalin-fixed, paraffin-embedded tissue. Developed for routine FFPE immunohistochemistry, with tonsil as positive control, six documented staining protocols for automated platforms and manual procedures, and 36 original ONCOdianova figures from 17 tumour types. Clone TC8 is named in the methods of five peer-reviewed studies covering several thousand human tumour samples in brightfield and Opal multiplex IHC with digital quantification.

View product dataOrderIHC galleryContact ↗
Evidence layer 01

Clone-specific datasheet and protocols

Datasheet DIA-TC8 (version 25 Feb 2025/08; product content identical to version 22 Feb 2022/09) documents identity, immunogen, formulation, reconstitution, storage, IHC starting range, tonsil control, membranous pattern, three automated platforms and four figures. The previous ONCOdianova product page adds six staining protocols.

Evidence layer 02

Five clone-specific publications

Blessin et al. 2020 and Eichenauer et al. 2021 (automated brightfield IHC, 1:200), Fraune et al. 2020 (manual IHC, 1:450) and two Opal multiplex studies with Ki67 (Blessin et al. 2021, Aging and Cellular Oncology; DIA-TC8 1:200, Opal 690) — “Oncodianova, mouse monoclonal antibody, Clone TC8” named in the methods, digital quantification with HALO/ImageScope.

Evidence layer 03

Documented applications and images

Brightfield IHC and fluorescence multiplex IHC on human FFPE tissue; 36 gallery figures, the four datasheet figures and one CD8 × CD112R/PVRIG multiplex of tonsil in which the anti-CD8 clone is named. No comparative or diagnostic claim is made.

Brightfield, datasheet and multiplex gallery: section P·03 ↓

P·02 Technical data

Controlled product data.

ProductAnti-CD8 (Human) from Mouse — mouse monoclonal antibody
CloneTC8 (monoclonal)
Catalog numbersDIA-TC8 (500 µl) · DIA-TC8-M (100 µl) — both listed in the datasheet; the previous product page lists DIA-TC8, 500 µl
TargetCD8 — T-cell surface glycoprotein CD8, co-receptor of the T-cell receptor on cytotoxic T cells. The datasheet names the target as CD8 without specifying the α chain (CD8A, Gene ID 925, UniProt P01732) or the β chain (CD8B, Gene ID 926, UniProt P10966)
ImmunogenRecombinant peptide of human CD8 (region, epitope and recognized CD8 chain not published)
IsotypeMouse IgG2a/κ
Host speciesMouse
ReactivityHuman
ConjugationUnconjugated
FormatLyophilized powder; antibody purified from culture supernatant; the previous product page states 100 µg per vial
ReconstitutionRestore DIA-TC8 to 500 µl (DIA-TC8-M to 100 µl) with sterile distilled water; gentle shaking for 10 minutes
FormulationPBS, pH 7.4, 1% BSA, 0.05% sodium azide
ApplicationsIHC on standard FFPE sections (datasheet: IHC-P) · fluorescence multiplex IHC (previous product page and homepage; two clone-specific publications)
IHC starting range1:100 – 1:200 (datasheet, general recommendation); 1:200 in the platform protocols and 1:100 in the manual microwave protocol of the previous product page; 1:200 and 1:450 in the published studies (study-specific); optimal dilution to be determined by the user for tissue, fixation, platform and detection system
Epitope retrievalHeat-induced epitope retrieval required (datasheet); pH 9 in the platform protocols (95–100 °C, 15–24 min), pH 7.8 by autoclave (121 °C, 5 min) or microwave in the manual protocols (previous product page)
Primary antibody incubation15–60 min depending on platform and protocol (previous product page, section P·04)
Positive controlTonsil
Staining patternMembranous (CD8-positive lymphocytes)
Automated platformsVentana Discovery Ultra, Leica Bond RX, Dako Autostainer Link 48 (datasheet); platform programs on the previous product page; Dako Autostainer Link 48 also in two published studies
StorageLyophilized at 2–8 °C; long-term at −20 °C (stable for at least one year); reconstituted at 2–8 °C short term (several weeks); avoid repeated freeze/thaw cycles
Associated antibodiesDIA-TG1 (anti-TIGIT, clone TG1) · DIA-R12 (anti-CD112R/PVRIG, clone R12) — as listed in the datasheet; each clone carries its own evidence
StatusResearch Use Only

The technical specifications above are documented in datasheet DIA-TC8 (version 25 Feb 2025/08), whose product content is identical to the version of 22 Feb 2022/09, and on the previous ONCOdianova product page where indicated; gene and protein entries link to their registries. Each laboratory must validate its own conditions.

P·04 Documented protocols

Datasheet procedure, six ONCOdianova protocols and published conditions.

Three sources, three scopes. Block A is the current datasheet and the starting point for in-house establishment. Block B contains the six protocols of the previous ONCOdianova product page for automated platforms and manual procedures. Block C shows the conditions reported in the clone-specific studies – they belong to the respective study protocol and are not a general recommendation for use. Dilutions are starting values; each laboratory validates tissue, fixation, platform and detection itself.

A · DatasheetImmunohistochemical staining of standard formalin-fixed paraffin sectionsDatasheet DIA-TC8 · version 25 Feb 2025/08 (identical wording in version 22 Feb 2022/09)

Preparation and epitope retrieval

  1. Reconstitution: restore DIA-TC8 to 500 µl with sterile distilled water (DIA-TC8-M to 100 µl), gentle shaking for 10 minutes
  2. Deparaffinize and rehydrate according to standard procedures
  3. Heat-induced epitope retrieval (HIER) is required; the datasheet does not state buffer, temperature or duration

Primary antibody and detection

  1. Use the antibody at 1:100–1:200 (IHC-P, general recommendation)
  2. Detection alternatives: indirect immunoenzyme labeling with a secondary antibody conjugate, biotin/(strept)avidin-based, soluble enzyme immune complex or polymer-based
  3. Suited for automated platforms (datasheet: Ventana Discovery Ultra, Leica Bond RX, Dako Autostainer Link 48); the platform programs are given in block B
  4. Run positive and negative controls in parallel; positive control: tonsil; expected pattern: membranous

For IHC protocols the datasheet refers to www.oncodianova.com (block B).

B · Previous product pageSix staining protocols: Dako, Leica, Ventana, manual (autoclave, microwave), two-colour immunofluorescenceONCOdianova product page DIA-TC8, section “IHC protocols” (as of 30 Aug 2026)

Dako Autostainer Link 48

  1. Pretreatment buffer: 15 min / 95 °C / pH 9
  2. Incubation primary antibody: 20 min / room temperature, dilution 1:200; linker: no
  3. HRP (polymer): 20 min / room temperature

Leica Bond RX

  1. Pretreatment buffer: 15 min / 100 °C / pH 9
  2. Incubation primary antibody: 15 min, dilution 1:200
  3. Post Primary: 8 min; HRP (polymer): 8 min

Ventana Discovery Ultra

  1. Pretreatment buffer: 24 min / 100 °C / pH 9
  2. Incubation primary antibody: 60 min / 38 °C, dilution 1:200
  3. Secondary antibody: 12 min / 36 °C; HRP (polymer): 12 min

Manual stain with autoclave

  1. Pretreatment buffer: 121 °C / 5 min / pH 7.8
  2. Incubation primary antibody: 60 min / 37 °C, dilution 1:200
  3. EnVision HRP rabbit/mouse: 30 min / 37 °C

Manual stain with microwave

  1. Pretreatment buffer: 90 s at 1000 W to boiling, then 15 min / 270 W / pH 7.8
  2. Incubation primary antibody: 60 min / 37 °C, dilution 1:100
  3. EnVision HRP rabbit/mouse: 30 min / 37 °C

Two-colour immunofluorescence, manual stain

  1. Position 1: antibody at pH 9; position 2: CD8
  2. Pretreatment buffer: 90 s at 1000 W to boiling, then 15 min / 270 W / pH 9
  3. Incubation primary antibody: 30 min / room temperature, dilution 1:200; HRP (polymer): 10 min / room temperature

The product page additionally states the reconstitution to 500 µl.

C · Published study conditionsBrightfield IHC (autostainer and manual) and Opal multiplex with Ki67 (study context, not a recommendation for use)Five clone-specific studies 2020–2021 (methods sections, PMC full texts)

C1 · Automated brightfield IHC, Dako Autostainer Link 48 (Blessin et al. 2020; Eichenauer et al. 2021)

  1. FFPE tissue microarrays; epitope retrieval PT Link, pH 9, 15 min at 98 °C
  2. Peroxidase block 5 min; “Oncodianova, mouse monoclonal antibody, Clone TC8, dilution 1:200”, 20 min at room temperature
  3. EnVision Flex HRP 20 min, DAB 10 min, haematoxylin 5 min; digitization Leica Aperio VERSA 8 (40×), analysis with HALO or ImageScope, CD8-positive cells/mm²

C2 · Manual brightfield IHC (Fraune et al. 2020, pancreatic carcinoma)

  1. Epitope retrieval: autoclave 5 min at 121 °C, Tris-EDTA-citrate buffer pH 7.8
  2. “Oncodianova, mouse monoclonal antibody, Clone TC8, 1:450”, 60 min at 37 °C; Dako EnVision; digital cell counting

C3 · Opal multiplex immunofluorescence CD8 × Ki67 (Blessin et al. 2021, Aging; Blessin et al. 2021, Cellular Oncology)

  1. Freshly cut 4 µm FFPE sections; initial retrieval at pH 9: microwave 15 min at 100 °C (Aging) or autoclave 30 min at 100–120 °C (Cellular Oncology)
  2. Position 1: Ki67 (Dianova, clone Ki-67P, DIA-670-P1; Opal 520 or Opal 570); antibody removal by microwave
  3. Position 2: CD8 “Oncodianova, Clone: TC8, Cat#: DIA-TC8”, 1:200, Opal 690; DAPI counterstain
  4. Image acquisition Leica Aperio VERSA 8; quantification with ImageScope or HALO (CD8+, Ki67+ and double-positive cells/mm²)

The 1:200 and 1:450 dilutions apply to the respective described procedures (platform, retrieval, incubation time and detection) and do not replace the datasheet starting range of 1:100–1:200. The publications name “Oncodianova” as supplier; the Ki67 reagent is from Dianova (historical brand name of ONCOdianova) and is not a product of this page.

P·05 Interpretation guide

How to read the staining.

Expected pattern

Membranous, CD8-positive lymphocytes

The datasheet describes a membranous visualization with tonsil as positive control. The ONCOdianova figures show CD8-positive lymphocytes as scattered, moderate or dense infiltrates in the tumour stroma, at the stroma–epithelium interface or between tumour cells, in carcinomas of 15 organs, in colon adenoma and in thymoma, without staining of the tumour cells in the depicted fields. These are documented fields, not a general expression map; the published normal-tissue panel reported splenic blood vessels as the only clearly CD8-positive non-lymphatic cell type under the study conditions.

Documented validation scope

Product validation and documented use

Clone TC8 was developed specifically for the routine immunohistochemical detection of CD8 in FFPE tissue and validated for the identification of CD8-positive tumour-infiltrating T cells (TILs) in order to allow the detection of CD8 in the tumour microenvironment, including validation for the detection of CD8-positive TILs in multiplex assays and an optimization of the signal-to-noise contrast. Five peer-reviewed studies independently used clone TC8 in brightfield IHC on 2,652 tumours of 84 entities with 608 normal tissues, on 1,163 renal tumours and on 551 pancreatic carcinomas, and DIA-TC8 in Opal multiplex IHC with Ki67 on 3,988 tumours of six cancer types and on normal, inflammatory and colorectal tissue, each with digital quantification.

Scope of evidence

CD8 expression is not cytotoxic function

CD8 IHC demonstrates the CD8 co-receptor on the cell surface. CD8-positive T cells are the classical cytotoxic effector cells,[1] but a large part of the CD8-positive T cells infiltrating human tumours are bystander cells without specificity for tumour antigens,[2] and CD8 alone does not show activation, proliferation or an executed cytotoxic response. A CD8-positive cell therefore identifies a CD8-expressing lymphocyte, not a proven tumour-specific cytotoxic T cell; cell assignment should consider morphology, tissue compartment and, where the research question requires it, further markers. No claim of superiority over other antibodies and no diagnostic, prognostic or therapeutic claim is made. For research use only.

P·06 Target background

CD8 in research.

CD8 is a cell-surface glycoprotein and co-receptor of the T-cell receptor. On conventional cytotoxic T cells it is expressed as a CD8αβ heterodimer encoded by the genes CD8A and CD8B; CD8αα homodimers occur on further lymphocyte populations. The co-receptor binds MHC class I and supports the recognition of peptide antigens presented by MHC class I molecules, the basis of the cytotoxic T-cell response.[1, 7] Tumour-specific cytotoxic T-cell clones have been derived from lung cancer patients,[3, 4, 5] and the activation of CD8-positive T cells is controlled by regulatory T cells[6] and by the immunosuppressive tumour microenvironment.[9]

In tissue studies, CD8 immunohistochemistry is used to determine the density and spatial distribution of CD8-positive lymphocytes in tumours: effector memory T cells in colorectal cancer were associated with early metastasis and survival in the published cohort,[8] and pre-existing CD8-positive T cells at the tumour margin were associated with responses to PD-1 blockade in the published melanoma cohort.[11] Neoantigen-directed T-cell responses and their broadening under checkpoint therapy are subjects of current research.[10, 12] The datasheet reactivity text summarizes this context: inhibitory receptors such as PD-1, CTLA-4 and TIGIT are activated in the immunosuppressive tumour microenvironment, and effective checkpoint blockade appears to be associated with the presence of CD8-positive T cells.

These statements describe the target and its research context. They are not evidence for the analytical performance of clone TC8 and do not establish which cell populations TC8 detects in a given specimen. Clone TC8 is a research tool for tissue-based CD8 studies; it carries no diagnostic, prognostic or therapeutic claim.

  • GenesCD8A — NCBI Gene 925 · CD8B — NCBI Gene 926
  • ProteinsT-cell surface glycoprotein CD8 α chain — UniProt P01732 · β chain — UniProt P10966
  • AliasesCD8 · Leu-2 · T8 · CD8α (p32) · CD8β (p37)
  • LocalizationCell-surface co-receptor — the basis of the membranous staining pattern
  • Interpretation limitBystander CD8-positive T cells without tumour specificity are abundant in human tumour infiltrates — Simoni et al. 2018 [2]
  • Related clonesCD8 × CD112R/PVRIG multiplex documented with R12; see also the ONCOdianova anti-TIGIT clones TG1 and TG2

Bracketed numbers refer to the target-literature list below. Target biology is kept separate from clone-specific product claims.

P·07 Publications

Clone-specific evidence and target literature.

Clone-specific evidence (clone TC8 / DIA-TC8 named in the source text)

  1. Blessin NC, Spriestersbach P, Li W, Mandelkow T, Dum D, Simon R, Hube-Magg C, Lutz F, Viehweger F, Lennartz M, Fraune C, Nickelsen V, Fehrle W, Göbel C, Weidemann S, Clauditz T, Lebok P, Möller K, Steurer S, Izbicki JR, Sauter G, Minner S, Jacobsen F, Luebke AM, Büscheck F, Höflmayer D, Wilczak W, Burandt E, Hinsch A. Prevalence of CD8+ cytotoxic lymphocytes in human neoplasms. Cellular Oncology (2020); 43(3):421–430. doi:10.1007/s13402-020-00496-7 · PMID 32141029 · PMC7214387
    Automated brightfield IHC (Dako Autostainer Link 48, PT Link pH 9, 1:200, 20 min at room temperature, EnVision Flex/DAB) on tissue microarrays: 2,652 evaluable tumours of 84 tumour entities and 608 normal tissues of 76 tissue types; digital quantification of CD8-positive cells per mm² (Aperio VERSA 8, HALO).    Peer-reviewed article · clone TC8 named in the methods
  2. Eichenauer T, Simmendinger L, Fraune C, Mandelkow T, Blessin NC, Kluth M, Hube-Magg C, Möller K, Clauditz T, Weidemann S, Dahlem R, Fisch M, Riechardt S, Simon R, Sauter G, Büscheck F, Rink M. High level of EZH2 expression is linked to high density of CD8-positive T-lymphocytes and an aggressive phenotype in renal cell carcinoma. World Journal of Urology (2021); 39(2):481–490. doi:10.1007/s00345-020-03200-4 · PMID 32303902 · PMC7910252
    Automated brightfield IHC (Dako Autostainer Link 48, PT Link pH 9, 1:200, 20 min at room temperature, EnVision Flex/DAB) on a tissue microarray of 1,809 renal tumours, 1,163 interpretable for CD8; digital quantification (Aperio VERSA 8, ImageScope).    Peer-reviewed article · clone TC8 named in the methods
  3. Blessin NC, Abu-Hashem R, Mandelkow T, Li W, Simon R, Hube-Magg C, Möller-Koop C, Witt M, Schmidt A, Büscheck F, Fraune C, Luebke AM, Möller K, Jacobsen F, Lutz F, Lennartz M, Steurer S, Sauter G, Höflmayer D, Tsourlakis MC, Hinsch A, Burandt E, Wilczak W, Minner S, Clauditz TS. Prevalence of proliferating CD8+ cells in normal lymphatic tissues, inflammation and cancer. Aging (2021); 13(11):14590–14603. doi:10.18632/aging.203113 · PMID 34083496 · PMC8221353
    Opal multiplex immunofluorescence CD8 × Ki67 on 4 µm FFPE sections (retrieval pH 9, microwave; Ki67 position 1, Opal 520; CD8 DIA-TC8 position 2, 1:200, Opal 690; DAPI): normal lymphatic tissues, inflammatory tissues, tumours and 765 evaluable colorectal carcinomas; quantification with ImageScope/HALO.    Peer-reviewed article · DIA-TC8 named in the methods table
  4. Blessin NC, Li W, Mandelkow T, Jansen HL, Yang C, Raedler JB, Simon R, Büscheck F, Dum D, Luebke AM, Hinsch A, Möller K, Menz A, Bernreuther C, Lebok P, Clauditz T, Sauter G, Marx A, Uhlig R, Wilczak W, Minner S, Krech T, Fraune C, Höflmayer D, Burandt E, Steurer S. Prognostic role of proliferating CD8+ cytotoxic Tcells in human cancers. Cellular Oncology (2021); 44(4):793–803. doi:10.1007/s13402-021-00601-4 · PMID 33864611 · PMC8338812
    Opal multiplex immunofluorescence CD8 × Ki67 on 4 µm FFPE sections (retrieval pH 9, autoclave; Ki67 position 1, Opal 570; CD8 DIA-TC8 position 2, 1:200, Opal 690; DAPI): 3,988 evaluable colorectal, breast, renal cell, ovarian, pancreatic and gastric carcinomas; quantification with HALO.    Peer-reviewed article · DIA-TC8 named in the methods
  5. Fraune C, Burandt E, Simon R, Hube-Magg C, Makrypidi-Fraune G, Kluth M, Büscheck F, Höflmayer D, Blessin NC, Mandelkow T, Li W, Perez D, Izbicki JR, Wilczak W, Sauter G, Schrader J, Neipp M, Mofid H, Daniels T, Isbert C, Clauditz TS, Steurer S. MMR Deficiency is Homogeneous in Pancreatic Carcinoma and Associated with High Density of Cd8-Positive Lymphocytes. Annals of Surgical Oncology (2020); 27(10):3997–4006. doi:10.1245/s10434-020-08209-y · PMID 32108923 · PMC7471097
    Manual brightfield IHC (autoclave 121 °C, 5 min, Tris-EDTA-citrate pH 7.8; 1:450, 60 min at 37 °C; Dako EnVision) on tissue microarrays of 597 pancreatic carcinomas, 551 evaluable for CD8; digital cell counting. Correction published 2022 (doi:10.1245/s10434-022-11798-5): an acknowledgement was added; methods and results unchanged.    Peer-reviewed article · clone TC8 named in the methods

Clone attribution verified in the PMC full texts on 30 Aug 2026 (methods sections and antibody tables). The five studies originate from the same pathology research environment (University Medical Center Hamburg-Eppendorf) and share the Dako Autostainer or Opal multiplex workflows; they document the published use of clone TC8 under the stated conditions and are not head-to-head comparisons with other CD8 antibodies.

Congress abstracts listed in the datasheet as references for clone TC8

  1. Blessin NC, Mandelkow T, Bady E, Hube-Magg C, Sauter G, Simon R, Fraune C, Lennartz M, Weidemann SA, Möller K, Höflmayer D. Abstract 3870: Patterns of CD112R expression in normal lymphatic tissues, inflammation and cancer. Cancer Research (Proceedings AACR Annual Meeting 2020) (2020); 80(16 Suppl):3870. doi:10.1158/1538-7445.AM2020-3870Congress abstract
  2. Simon R, Blessin NC, Mandelkow T, Bady E, Hube-Magg C, Sauter G, Lennartz M, Fraune C, Weidemann SA, Möller K, Büscheck F. Abstract 4970: Prognostic role of CD112R, PD-1 and Ki67 expression in CD8+cytotoxic T cells in colorectal cancer. Cancer Research (Proceedings AACR Annual Meeting 2020) (2020); 80(16 Suppl):4970. doi:10.1158/1538-7445.AM2020-4970Congress abstract

The datasheet and the previous product page list these two AACR 2020 abstracts among the “specific references for clone TC8”. The abstract texts (Crossref, 30 Aug 2026) name CD8 and Ki67 but not the antibody clones; they are listed for completeness and are not counted as clone-specific evidence.

Target literature cited on the previous product page and in the approved content

  1. Zhang N, Bevan MJ. CD8(+) T cells: foot soldiers of the immune system. Immunity (2011); 35(2):161–168. doi:10.1016/j.immuni.2011.07.010 · PMID 21867926Target biology · review
  2. Simoni Y et al. Bystander CD8+ T cells are abundant and phenotypically distinct in human tumour infiltrates. Nature (2018); 557(7706):575–579. doi:10.1038/s41586-018-0130-2 · PMID 29769722Target biology
  3. Weynants P, Thonnard J, Marchand M, Delos M, Boon T, Coulie PG. Derivation of tumor-specific cytolytic T-cell clones from two lung cancer patients with long survival. American Journal of Respiratory and Critical Care Medicine (1999); 159(1):55–62. doi:10.1164/ajrccm.159.1.9805073 · PMID 9872818Target biology
  4. Echchakir H, Vergnon I, Dorothée G, Grunenwald D, Chouaib S, Mami-Chouaib F. Evidence for in situ expansion of diverse antitumor-specific cytotoxic T lymphocyte clones in a human large cell carcinoma of the lung. International Immunology (2000); 12(4):537–546. doi:10.1093/intimm/12.4.537 · PMID 10744655Target biology
  5. Karanikas V et al. High frequency of cytolytic T lymphocytes directed against a tumor-specific mutated antigen detectable with HLA tetramers in the blood of a lung carcinoma patient with long survival. Cancer Research (2001); 61(9):3718–3724. PMID 11325844Target biology
  6. Piccirillo CA, Shevach EM. Cutting edge: control of CD8+ T cell activation by CD4+CD25+ immunoregulatory cells. Journal of Immunology (2001); 167(3):1137–1140. doi:10.4049/jimmunol.167.3.1137 · PMID 11466326Target biology
  7. Bossi G, Trambas C, Booth S, Clark R, Stinchcombe J, Griffiths GM. The secretory synapse: the secrets of a serial killer. Immunological Reviews (2002); 189:152–160. doi:10.1034/j.1600-065x.2002.18913.x · PMID 12445272Target biology · review
  8. Pagès F et al. Effector memory T cells, early metastasis, and survival in colorectal cancer. New England Journal of Medicine (2005); 353(25):2654–2666. doi:10.1056/NEJMoa051424 · PMID 16371631Target biology
  9. Gajewski TF, Meng Y, Harlin H. Immune suppression in the tumor microenvironment. Journal of Immunotherapy (2006); 29(3):233–240. doi:10.1097/01.cji.0000199193.29048.56 · PMID 16699366Target biology · review
  10. Kvistborg P et al. Anti-CTLA-4 therapy broadens the melanoma-reactive CD8+ T cell response. Science Translational Medicine (2014); 6(254):254ra128. doi:10.1126/scitranslmed.3008918 · PMID 25232180Target biology
  11. Tumeh PC et al. PD-1 blockade induces responses by inhibiting adaptive immune resistance. Nature (2014); 515(7528):568–571. doi:10.1038/nature13954 · PMID 25428505Target biology
  12. Schumacher TN, Schreiber RD. Neoantigens in cancer immunotherapy. Science (2015); 348(6230):69–74. doi:10.1126/science.aaa4971 · PMID 25838375Target biology · review

Titles quoted verbatim; PubMed status and Crossref metadata (including retraction, correction and expression-of-concern notices) checked on 30 Aug 2026 for every entry: no retraction and no expression of concern. Entries 1 and 2 are the review and interpretation sources of the approved content; entries 3–12 are the ten “general references” of the previous ONCOdianova product page.

P·08 FAQ

Frequent scientific questions.

What does anti-CD8 clone TC8 detect?

TC8 is a mouse monoclonal antibody (IgG2a/κ) raised against a recombinant peptide of human CD8, the T-cell co-receptor of the T-cell receptor. The datasheet names the target as CD8 without specifying the α (CD8A) or β (CD8B) chain; the recognized chain and epitope are not published. It is offered as a research reagent for immunohistochemistry on human formalin-fixed, paraffin-embedded (FFPE) tissue with a membranous staining pattern of CD8-positive lymphocytes.

Is TC8 documented for FFPE immunohistochemistry?

Yes. The datasheet states that clone TC8 was developed specifically for the routine immunohistochemical detection of CD8 in FFPE tissue specimens and gives a starting range of 1:100 to 1:200. The previous ONCOdianova product page documents six protocols (Dako Autostainer Link 48, Leica Bond RX, Ventana Discovery Ultra, manual autoclave, manual microwave, two-colour immunofluorescence), and 36 original ONCOdianova figures show CD8-positive lymphocytes in 17 tumour types.

Are there peer-reviewed publications using clone TC8?

Yes. Five peer-reviewed studies name clone TC8 or catalogue number DIA-TC8 in their methods: Blessin et al. 2020 (Cellular Oncology; 2,652 tumours of 84 entities and 608 normal tissues), Eichenauer et al. 2021 (World Journal of Urology; renal cell carcinoma), Blessin et al. 2021 (Aging; CD8 × Ki67 multiplex in normal, inflammatory and tumour tissue), Blessin et al. 2021 (Cellular Oncology; CD8 × Ki67 multiplex in 3,988 tumours of six cancer types) and Fraune et al. 2020 (Annals of Surgical Oncology; pancreatic carcinoma). The clone attribution was verified in the full texts on 30 August 2026.

Is TC8 validated for fluorescence multiplex IHC?

Yes. Clone TC8 was validated for the detection of CD8-positive TILs in multiplex assays; the previous product page gives a manual two-colour immunofluorescence protocol with CD8 in position 2, and datasheet DIA-R12 shows a CD8 × CD112R/PVRIG multiplex of normal tonsil with DIA-TC8. Independently published evidence includes two peer-reviewed Opal multiplex studies (Blessin et al. 2021, Aging and Cellular Oncology) that used DIA-TC8 at 1:200 in position 2 with Opal 690 together with Ki67. Every new panel must be verified for tissue, antibody order, retrieval, dilution and detection.

Which dilution should be used?

The datasheet gives 1:100 to 1:200 as a general recommendation for IHC on FFPE sections. The platform protocols of the previous product page use 1:200 (Dako, Leica, Ventana, manual autoclave, two-colour immunofluorescence) and 1:100 for the manual microwave protocol. Published studies used 1:200 (Dako Autostainer Link 48 and Opal multiplex) and 1:450 (manual autoclave protocol, 60 min at 37 °C). Dilution, retrieval and incubation belong together; each laboratory establishes its own conditions.

Which epitope retrieval is used for TC8?

Heat-induced epitope retrieval is required (datasheet). The platform protocols use pH 9 (15 min at 95 °C for Dako Autostainer Link 48, 15 min at 100 °C for Leica Bond RX, 24 min at 100 °C for Ventana Discovery Ultra); the manual protocols use pH 7.8 with autoclave (121 °C, 5 min) or microwave. Published studies used PT Link pH 9 (15 min at 98 °C), autoclave pH 7.8 and, for multiplex, pH 9 by microwave or autoclave.

Which positive control and staining pattern are expected?

Tonsil is the positive control named in the datasheet; the expected pattern is membranous staining of CD8-positive lymphocytes. The ONCOdianova figures show CD8-positive lymphocytes within tumour stroma and between tumour cells in carcinomas of the prostate, lung, oesophagus, stomach, ovary, vulva, cervix, vagina, kidney, urinary bladder, liver, anus, pancreas, thyroid and oral cavity, in colon adenoma and in thymoma.

Can TC8 be used on automated staining platforms?

Yes. The datasheet states suitability for the Ventana Discovery Ultra, Leica Bond RX and Dako Autostainer Link 48, and the previous product page gives a program for each platform (section P·04). Two published studies used the Dako Autostainer Link 48 with PT Link retrieval; the published multiplex stainings were performed manually with Opal reagents.

Does CD8 positivity prove a cytotoxic T cell?

No. CD8 immunostaining demonstrates the CD8 protein on the cell surface. CD8 is expressed predominantly by cytotoxic T cells, but tumour-infiltrating CD8-positive T cells include bystander cells without tumour specificity, and CD8 alone does not show activation, proliferation or cytotoxic function. Cell identity and functional state should be assessed with morphology and, depending on the research question, additional markers such as Ki67 in the published multiplex studies.

What is the documented validation scope of clone TC8?

Clone TC8 was developed specifically for the routine IHC detection of CD8 in FFPE tissue and validated for the identification of CD8-positive tumour-infiltrating T cells in order to allow the detection of CD8 in the tumour microenvironment, including validation for CD8-positive TILs in multiplex assays. Independently published clone-specific evidence includes five peer-reviewed studies with several thousand human FFPE tumour samples in brightfield and Opal multiplex IHC with digital quantification.

Which format and formulation does DIA-TC8 have?

DIA-TC8 is a lyophilized antibody purified from culture supernatant, reconstituted to 500 µl with sterile distilled water; the datasheet additionally lists DIA-TC8-M, reconstituted to 100 µl. The datasheet gives the formulation as PBS, pH 7.4, with 1% BSA and 0.05% sodium azide; the previous product page states 100 µg per vial. Store lyophilized at 2–8 °C, long term at −20 °C; reconstituted at 2–8 °C for several weeks; avoid repeated freeze/thaw cycles.

Is TC8 intended for diagnostic use?

No. TC8 is intended for research use only and is not intended for diagnostic or therapeutic procedures. The published studies are research studies; they establish neither a diagnostic nor a prognostic use of the antibody.

P·09 Documents

Data package.

Datasheet

DIA-TC8

Product datasheet, version 25 Feb 2025/08 (product content identical to the version of 22 Feb 2022/09; updated distribution address). Identity, immunogen, formulation, reconstitution, storage, instructions for use, four figures and the reference list.

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PDF · version 2025/08 · 216 KB

IHC gallery

CD8 IHC gallery

The “CD8 IHC-Gallery” of the previous website is integrated in section P·03 of this page with 36 figures and their legends, plus the datasheet figures and one multiplex figure.

Go to gallery ↓

38 figures · brightfield, datasheet, multiplex

Protocols

IHC protocols

The six staining protocols of the previous product page (Dako Autostainer Link 48, Leica Bond RX, Ventana Discovery Ultra, manual autoclave, manual microwave, two-colour immunofluorescence) are reproduced in section P·04.

Go to protocols ↓

6 protocols · section P·04

Safety

MSDS

Material safety data sheet (ONCOdianova, all lyophilized antibodies).

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PDF · V02 · 216 KB

Ordering. ONCOdianova products are purchased through our distribution partner BIOZOL Diagnostica Vertrieb GmbH, Oehleckerring 11–13, 22419 Hamburg, Germany — order requests by e-mail: order@biozol.de (CC info@oncodianova.com). See also order information and distributors (in preparation).

The technical data on this page are taken from datasheet DIA-TC8 (version 25 Feb 2025/08; product content identical to the version of 22 Feb 2022/09) and from the previous ONCOdianova product page where indicated. Related: R12 (anti-CD112R/PVRIG) · TG1 (anti-TIGIT) · TG2 (anti-TIGIT) · FX3 (FOXP3) · KK3 (CD73).

For Research Use Only. Not for diagnostic or therapeutic use.