Anti-MHC Class II antibody [MRC OX-6] (ab23990)


  • Product name
    Anti-MHC Class II antibody [MRC OX-6]
    See all MHC Class II primary antibodies
  • Description
    Mouse monoclonal [MRC OX-6] to MHC Class II
  • Host species
  • Specificity
    This antibody recognises a monomorphic determinant of the rat I-A antigen present on B lymphocytes, dendritic cells, some macrophages and certain epithelial cells. The antibody cross-reacts with certain mouse strains of MHC haplotypes k and s and analysis of recombinant strains showed that the determinants mapped to the I-A region of the mouse MHC.
  • Tested applications
    Suitable for: WB, ICC, IHC-P, ICC/IF, Flow Cyt, IHC-Fr, IHC (PFA fixed)more details
  • Species reactivity
    Reacts with: Rat
    Predicted to work with: Mouse
  • Immunogen

    Thymocyte membrane glycoprotein (Rat).

  • Positive control
    • This antibody gave a positive result in IHC in the following FFPE tissue: Rat normal spleen.
  • General notes

    This antibody clone is manufactured by Abcam.

    If you require this antibody in a particular buffer formulation or a particular conjugate for your experiments, please contact or you can find further information here.


  • Form
  • Storage instructions
    Shipped at 4°C. Store at +4°C short term (1-2 weeks). Upon delivery aliquot. Store at -20°C long term.
  • Storage buffer
    pH: 7.4
    Preservative: 0.02% Sodium azide
    Constituents: PBS, 6.97% L-Arginine
  • Concentration information loading...
  • Purity
    Immunogen affinity purified
  • Clonality
  • Clone number
    MRC OX-6
  • Myeloma
  • Isotype
  • Research areas


Our Abpromise guarantee covers the use of ab23990 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

Application Abreviews Notes
WB Use at an assay dependent concentration. Predicted molecular weight: 29 kDa.
ICC Use at an assay dependent concentration.
IHC-P Use at an assay dependent concentration.
ICC/IF Use at an assay dependent concentration.
Flow Cyt Use 10µl for 106 cells.

ab170190 - Mouse monoclonal IgG1, is suitable for use as an isotype control with this antibody.

IHC-Fr Use at an assay dependent concentration.
IHC (PFA fixed) 1/100.


  • Function
    Binds peptides derived from antigens that access the endocytic route of antigen presenting cells (APC) and presents them on the cell surface for recognition by the CD4 T-cells. The peptide binding cleft accomodates peptides of 10-30 residues. The peptides presented by MHC class II molecules are generated mostly by degradation of proteins that access the endocytic route, where they are processed by lysosomal proteases and other hydrolases. Exogenous antigens that have been endocytosed by the APC are thus readily available for presentation via MHC II molecules, and for this reason this antigen presentation pathway is usually referred to as exogenous. As membrane proteins on their way to degradation in lysosomes as part of their normal turn-over are also contained in the endosomal/lysosomal compartments, exogenous antigens must compete with those derived from endogenous components. Autophagy is also a source of endogenous peptides, autophagosomes constitutively fuse with MHC class II loading compartments. In addition to APCs, other cells of the gastrointestinal tract, such as epithelial cells, express MHC class II molecules and CD74 and act as APCs, which is an unusual trait of the GI tract. To produce a MHC class II molecule that presents an antigen, three MHC class II molecules (heterodimers of an alpha and a beta chain) associate with a CD74 trimer in the ER to form an heterononamer. Soon after the entry of this complex into the endosomal/lysosomal system where antigen processing occurs, CD74 undergoes a sequential degradation by various proteases, including CTSS and CTSL, leaving a small fragment termed CLIP (class-II-associated invariant chain peptide). The removal of CLIP is facilitated by HLA-DM via direct binding to the alpha-beta-CLIP complex so that CLIP is released. HLA-DM stabilizes MHC class II molecules until primary high affinity antigenic peptides are bound. The MHC II molecule bound to a peptide is then transported to the cell membrane surface. In B cells, the interaction between HLA-DM and MHC class II molecules is regulated by HLA-DO. Primary dendritic cells (DCs) also to express HLA-DO. Lysosomal miroenvironment has been implicated in the regulation of antigen loading into MHC II molecules, increased acidification produces increased proteolysis and efficient peptide loading.
  • Sequence similarities
    Belongs to the MHC class II family.
    Contains 1 Ig-like C1-type (immunoglobulin-like) domain.
  • Cellular localization
    Cell membrane. Endoplasmic reticulum membrane. Golgi apparatus > trans-Golgi network membrane. Endosome membrane. Lysosome membrane. The MHC class II complex transits through a number of intracellular compartments in the endocytic pathway until it reaches the cell membrane for antigen presentation.
  • Information by UniProt
  • Database links
  • Alternative names
    • D6S221E antibody
    • DMA antibody
    • DMB antibody
    • DP beta 1 antibody
    • DP beta 1 chain antibody
    • DP(W4) beta chain antibody
    • DPB 1 antibody
    • DPB1 antibody
    • DPB1_HUMAN antibody
    • DRB antibody
    • H2Ea antibody
    • HLA class II histocompatibility antigen antibody
    • HLA class II histocompatibility antigen DM beta chain antibody
    • HLA class II histocompatibility antigen, DP beta 1 chain antibody
    • HLA class II histocompatibility antigen, DP(W4) beta chain antibody
    • HLA DMB antibody
    • HLA DP1A antibody
    • HLA DPB1 antibody
    • HLA SB alpha chain antibody
    • HLA-A antibody
    • HLA-A histocompatibility type antibody
    • HLA-DP antibody
    • HLA-DP histocompatibility type, beta-1 subunit antibody
    • HLA-DP1B antibody
    • HLA-DPB antibody
    • HLA-DPB1 antibody
    • HLADM antibody
    • HLADP1B antibody
    • HLASB antibody
    • HLASB histocompatibility type antibody
    • Human MHC class II HLA SB alpha antibody
    • LA class II histocompatibility antigen DP alpha 1 chain antibody
    • Major histocompatibility complex class II antibody
    • Major histocompatibility complex class II DP alpha 1 antibody
    • Major histocompatibility complex class II DP beta 1 antibody
    • Major histocompatibility complex, class I, A antibody
    • MHC class II antigen DMB antibody
    • MHC class II antigen DPB1 antibody
    • MHC class II DP3 alpha antibody
    • MHC class II DPA1 antibody
    • MHC class II HLA-DP-beta-1 antibody
    • MHC DPB1 antibody
    • MHC HLA DPB1 antibody
    • PLT1 antibody
    • Primed lymphocyte test 1 antibody
    • RING6 antibody
    • RING7 antibody
    see all


  • Immunohistochemistical detection of MHC Class II using antibody ab23990 on PFA-fixed rat spleen tissue sections. Antibody diluted at 1/100 and incubated for2 hours in  TBS/BSA/Tween/azide. Secondary antibody: anti mouse IgG conjugated to biotin (1/100). After dissection of spleen from PFA-perfused specimen it was sampled and further immersion-fixed for two Hrs. After subsequent immersion in 30% Sucrose, specimens were snap-frozen. Before immunostaining, the 8 micron sections were placed in a 60 degree C oven for 60 mins to enhance adhesion. The submitted image shows white pulp (PALS) and a small area of red pulp (RP-upper left). The Periarteriolar Sheath (PALS) with it's Central Arteriole/artery (CA)shows many positive cells (B-lymphocytes and Macrophages) and negative lymphocytes (T-cells?). The Marginal Sinus (MS) is clearly seen between the PALS and the Marginal Zone (MZ). There is a clear Germinal Centre (GS) in this image. Lymphoid tissue is not my

    See Abreview

  • ab23990 staining MHC Class II in Rat spleen tissue by Immunohistochemistry (Frozen sections). The sections were fixed in PFA prior to blocking with 10% serum for 20 minutes at 24°C. The primary antibody was diluted 1/100 in PBS and incubated with the sample for 16 hours at 4°C. An Alexa Fluor® 488-conjugated donkey anti-mouse polyclonal was used as the secondary antibody, diluted 1/1000 for 1 hour at room temperature. Counterstained with Hoechst 33258 (blue) for 10 minutes at room temperature

    See Abreview

  • IHC image of MHC Class II staining in Rat normal spleen formalin fixed paraffin embedded tissue section, performed on a Leica BondTM system using the standard protocol F. The section was pre-treated using heat mediated antigen retrieval with sodium citrate buffer (pH6, epitope retrieval solution 1) for 20 mins. The section was then incubated with ab23990, 10µg/ml, for 15 mins at room temperature and detected using an HRP conjugated compact polymer system. DAB was used as the chromogen. The section was then counterstained with haematoxylin and mounted with DPX.

    For other IHC staining systems (automated and non-automated) customers should optimize variable parameters such as antigen retrieval conditions, primary antibody concentration and antibody incubation times.


This product has been referenced in:
  • Shall G  et al. Effects of Passage Number and Differentiation Protocol on the Generation of Dopaminergic Neurons from Rat Bone Marrow-Derived Mesenchymal Stem Cells. Int J Mol Sci 19:N/A (2018). Flow Cyt ; Rat . Read more (PubMed: 29498713) »
  • Nau C  et al. Tissue engineered vascularized periosteal flap enriched with MSC/EPCs for the treatment of large bone defects in rats. Int J Mol Med 39:907-917 (2017). Read more (PubMed: 28259928) »

See all 20 Publications for this product

Customer reviews and Q&As

Immunocytochemistry/ Immunofluorescence
Mouse Cell (Brain, Hypothalamus)
Yes - 0.1% Tween-20 in PBS
Brain, Hypothalamus
Blocking step
BSA as blocking agent for 40 minute(s) · Concentration: 1% · Temperature: 25°C

Miss. Chia-Li Lin

Verified customer

Submitted Nov 19 2015

Thank you for contacting us.

We do sell this specific clone to MHC II. The product number for this antibody is ab23990. It is sold at 125ug size at a concentration of 1mg/ml. These are currently in stock both in the US and at our other off...

Read More

Thank you for your enquiry.

I would like to reassure you that our antibodies have all been tested successfully and would be covered by our guarantee in the applications listed on the datasheets. Therefore, any antibody tested in the specie...

Read More
Abcam guarantees this product to work in the species/application used in this Abreview.
Rat Cultured Cells (33B)
Blocking step
Serum as blocking agent for 30 minute(s) · Concentration: 10% · Temperature: 24°C

Abcam user community

Verified customer

Submitted Jul 06 2012

Abcam guarantees this product to work in the species/application used in this Abreview.
Immunocytochemistry/ Immunofluorescence
Rat Cell (B50 Neuroblastoma Cell line)
B50 Neuroblastoma Cell line
Blocking step
Serum as blocking agent for 20 minute(s) · Concentration: 10% · Temperature: 24°C

Abcam user community

Verified customer

Submitted Jun 21 2012

Thanks again for your call last week amd for your question about this antibody. I sincerely apologize but I just received further information from the lab, and the last email I sent you contained misinformation. This antibody has actually been tested i...

Read More

Thank you for your call yesterday and for your patience while I have been in touch with the lab. I have attached a document that shows what strains have been tested with ab23990. According to the lab, we have not tested C57/Bl6, however every strain te...

Read More
Abcam guarantees this product to work in the species/application used in this Abreview.
Immunohistochemistry (Frozen sections)
Rat Tissue sections (Spleen)
Blocking step
Serum as blocking agent for 20 minute(s) · Concentration: 10% · Temperature: 24°C

Abcam user community

Verified customer

Submitted Sep 23 2011

Thank you for your patience. I have received the following explanation from the lab that will hopefully help to answer your questions: Please see below for a breakdown of rat and mouse MHC molecules. Rat MHC Class II molecules are RT1.B, RT1....

Read More

Thank you for your enquiry. Permeabilisation is normally required for intracellular Flow Cytometry as this involves whole cells. However, for immunohistochemistry (whether using fluorescence or HRP), the cells have already been sliced, so further p...

Read More

1-10 of 12 Abreviews or Q&A


Sign up