• Product name

    Anti-CD74 antibody [MRC OX3]
    See all CD74 primary antibodies
  • Description

    Mouse monoclonal [MRC OX3] to CD74
  • Host species

  • Specificity

    Recognises a polymorphic determinant of rat Ia antigen (RT1.Bu) present on Lewis, Wistar and AO strain rats but not BN, DA or PVG/c strains. The antibody cross reacts with mouse strains (MHC haplotypes b and s) and analysis of recombinant mouse strains showed that the determinants mapped to the I-A region. It recognises Ia antigens on B-cells, dendritic cells and certain epithelial cells. It is particularly useful for distinguishing Ia positive cells from different rat strains, eg for recognising cells of donor origin in bone marrow reconstituted radiation chimeras.
  • Tested applications

    Suitable for: IHC-R, IHC-P, IHC-Fr, Flow Cytmore details
  • Species reactivity

    Reacts with: Mouse, Rat
  • Immunogen

    Rat thymocyte membrane glycoproteins


  • Form

  • Storage instructions

    Shipped at 4°C. Store at +4°C short term (1-2 weeks). Upon delivery aliquot. Store at -20°C or -80°C. Avoid freeze / thaw cycle.
  • Storage buffer

    Preservative: 0.09% Sodium Azide
    Constituents: 1% BSA, PBS, pH 7.4
  • Concentration information loading...
  • Purity

    Protein G purified
  • Purification notes

    Purified IgG prepared by ion exchange chromatography from tissue culture supernatant
  • Clonality

  • Clone number

    MRC OX3
  • Myeloma

  • Isotype

  • Research areas


Our Abpromise guarantee covers the use of ab22348 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
IHC-R Use at an assay dependent concentration.
IHC-P Use at an assay dependent concentration.
IHC-Fr Use at an assay dependent concentration.
Flow Cyt 1/100.

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



  • Function

    Plays a critical role in MHC class II antigen processing by stabilizing peptide-free class II alpha/beta heterodimers in a complex soon after their synthesis and directing transport of the complex from the endoplasmic reticulum to the endosomal/lysosomal system where the antigen processing and binding of antigenic peptides to MHC class II takes place. Serves as cell surface receptor for the cytokine MIF.
  • Sequence similarities

    Contains 1 thyroglobulin type-1 domain.
  • Cellular localization

    Cell membrane. Endoplasmic reticulum membrane. Golgi apparatus > trans-Golgi network. Endosome. Lysosome. Transits through a number of intracellular compartments in the endocytic pathway. It can either undergo proteolysis or reach the cell membrane.
  • Information by UniProt
  • Database links

  • Alternative names

    • CD 74 antibody
    • CD74 antibody
    • CD74 antigen (invariant polypeptide of major histocompatibility complex, class II antigen-associated) antibody
    • CD74 antigen antibody
    • CD74 molecule antibody
    • CD74 molecule, major histocompatibility complex, class II invariant chain antibody
    • CLIP antibody
    • DHLAG antibody
    • Gamma chain of class II antigens antibody
    • HG2A_HUMAN antibody
    • HLA class II histocompatibility antigen gamma chain antibody
    • HLA DR antigens associated invariant chain antibody
    • HLA DR gamma antibody
    • HLA-DR antigens-associated invariant chain antibody
    • HLA-DR-gamma antibody
    • HLADG antibody
    • HLADR antigens associated invariant chain antibody
    • Ia antigen associated invariant chain antibody
    • Ia antigen-associated invariant chain antibody
    • Ia associated invariant chain antibody
    • Ia gamma antibody
    • Ii antibody
    • Invariant polypeptide of major histocompatibility complex class II antigen associated antibody
    • la-gamma antibody
    • Major histocompatibility complex class II invariant chain antibody
    • MHC HLA DR gamma chain antibody
    • MHC HLA-DR gamma chain antibody
    • p33 antibody
    • p35 antibody
    • Protein 41 antibody
    see all


ab22348 has not yet been referenced specifically in any publications.

Customer reviews and Q&As

1-3 of 3 Abreviews or Q&A


We do not have data that answers your questions but the following paper should contain information about the production and characterization of the OX3 clone. I do not have access to the journal to confirm.

McMaster, W. R. & Williams, A. F. (1979). Identification of Ia glycoproteins in the rat thymus and purification from rat spleen. European Journal of Immunology 9,426-433.


The paper at the following link contains data for specificity of the antibody for various strains, but it does not have an explanation for the specificity.


Read More


The antibody does not require antigen retrieval. The rest of the protocol is standard, and can be found on our website at the following link.


For a secondary antibody, we have several choices. I recommend either one of our Expose kits (https://www.abcam.com/index.html?pageconfig=resource&rid=12865) or the mouse-on-mouse polymer kit I mentioned in my previous e-mail, ab127055. The Expose kit that contains HRP/DAB is ab80436

Click here (or use the following: https://www.abcam.com/index.html?datasheet=80436).

Click here (or use the following: https://www.abcam.com/index.html?datasheet=127055).

If you just want a secondary antibody, I recommend anti-mouse IgG conjugated to HRP, ab97046.

Click here (or use the following: https://www.abcam.com/index.html?datasheet=97046).

Read More


Yes, "IHC-P" refers to immunohistochemistry of formalin-fixed, paraffin-embedded tissue.

Regarding mouse reactivity, it has been confirmed that the antibody reacts with mouse strains (MHC haplotypes b and s).

If you are using a secondary antibody, anti-mouse IgG, and encounter high background due to reactivity with endogenous mouse IgG, please consider using our "mouse-on-mouse" polymer system, ab127055.

Read More

For licensing inquiries, please contact partnerships@abcam.com

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