Anti-CD74 Rabbit Polyclonal Antibody for WB, IF/ICC, IHC-P, ELISA - P04233

Core Product Specifications and Parameters

Biological Background: CD74 Function and Localization

• CD74, also known as HLA class II histocompatibility antigen gamma chain or invariant chain (Ii), is a critical chaperone in MHC class II antigen processing and presentation. It serves as a cell surface receptor for macrophage migration inhibitory factor (MIF).
• The protein binds to the peptide-binding site of MHC class II alpha/beta heterodimers, forming an alpha-beta-CLIP complex that prevents premature peptide loading until HLA-DM facilitates CLIP release in the endosome.
• CD74 stabilizes the conformation of mature cathepsin L (CTSL) by binding to its active site, acting as a chaperone to maintain a pool of active enzyme in endocytic compartments and the extracellular space of antigen-presenting cells.
• The p41 isoform of CD74 demonstrates antiviral activity by blocking endosomal entry of Ebola virus and coronaviruses, including SARS-CoV-2, through disruption of cathepsin-mediated viral glycoprotein processing. Related references: PMID:32855215
• Subcellularly, CD74 is found at the cell membrane, endoplasmic reticulum, Golgi apparatus, trans-Golgi network, endosomes, and lysosomes; it is also secreted.
• In B cells, two major isoforms represent approximately 10% and 70% of total CD74 expression, respectively.
• Post-translational modifications include phosphorylation, glycosylation, proteoglycan attachment, and disulfide bond formation, as indicated by UniProt annotation.

Experimental Guidance and Technical Tips

• The immunogen corresponds to amino acids 73-232 of human CD74 (NP_004346.1), covering the CLIP region; verify sequence conservation if using in species other than human and rat.
• For Western blot (WB), the predicted molecular weight is 34 kDa, but glycosylation and isoform variants may cause band shifts; validate detection in your experimental system.
• In immunohistochemistry-paraffin (IHC-P), consider optimizing antigen retrieval protocols, as CD74 localizes to multiple intracellular compartments.
• For immunofluorescence/immunocytochemistry (IF/ICC), permeabilization conditions should be tested due to the combined membrane and intracellular localization of CD74.
• When using ELISA, note that CD74 can be secreted; suitable sample preparation and assay validation are recommended.

CamelBio: Your One-Stop Sourcing Bridge

CamelBio is a specialized one-stop partner for IVD raw materials, offering validated antibody pairs, optimized monoclonal/polyclonal antibodies, bulk ancillary reagents, and rare target sourcing solutions. This anti-CD74 polyclonal antibody supports research in immunology, infectious disease, and cancer biology, and CamelBio can assist in scaling your projects from discovery through to clinical application with flexible supply and technical support.