Anti-SIGLEC3/CD33 Rabbit Polyclonal Antibody for WB, IHC-P, IF/ICC, ELISA - P20138

Core Product Specifications and Parameters

Biological Background: SIGLEC3/CD33 Function and Localization

• CD33 (Siglec-3, p67, gp67) is a single-pass type I membrane protein and a member of the sialic acid-binding immunoglobulin-like lectin (Siglec) family, characterized by an N-terminal V-set Ig-like domain and a cytoplasmic tail containing two immunoreceptor tyrosine-based inhibitory motifs (ITIMs).
• It functions as an inhibitory receptor; upon engagement of sialic acid ligands or C1q, the ITIMs are phosphorylated by Src-like kinases such as LCK, leading to recruitment of tyrosine phosphatases PTPN6/SHP-1 and PTPN11/SHP-2, which downregulate immune signaling (PubMed:10887109, 10556798, 10206955). Related references: PMID:10887109, PMID:10556798, PMID:10206955
• Preferentially binds alpha-2,3- and alpha-2,6-linked sialic acids, with higher avidity for alpha-2,6-linked glycans (PubMed:7718872). Related references: PMID:7718872
• The repressive effect of CD33 on monocyte activation involves phosphoinositide 3-kinase (PI3K) signaling (PubMed:15597323). Related references: PMID:15597323
• Subcellularly, CD33 localizes to the plasma membrane and peroxisomes.
• Expressed specifically on cells of monocytic/myeloid lineage, including monocytes, macrophages, and granulocytes; in the central nervous system, it is predominantly found on microglial cells.
• Keywords highlight its roles in cell adhesion, immune regulation, and alternative splicing, with documented glycoprotein and phosphoprotein modifications.

Experimental Guidance and Technical Tips

• The immunogen corresponds to amino acids 49-259 of human CD33 (extracellular domain), which includes the sialic acid-binding V-set Ig domain. This design targets the native conformation, making it suitable for detecting surface-expressed CD33 in flow cytometry-like applications (IF/ICC) and immunohistochemistry (IHC-P).
• For Western blot (WB), the expected protein weight is ~40 kDa, but due to glycosylation, the observed band may appear at a higher molecular weight. It is advisable to run a reducing gel and validate with appropriate positive controls (e.g., myeloid cell lines like HL-60 or THP-1).
• When using this polyclonal antibody in immunoprecipitation or ELISA, consider that the polyclonal nature may enhance sensitivity but could also increase background; optimization of blocking and wash conditions is recommended.
• Cross-reactivity with mouse and rat implies conserved epitopes; however, sequence alignment should be checked for specific experimental contexts, and validation in the relevant species is essential.
• For IHC-P, antigen retrieval methods (e.g., citrate buffer, pH 6.0) and tissue fixation conditions should be optimized, as epitope accessibility may vary.
• This antibody is suitable as a capture or detection component in sandwich ELISA if paired with a matched antibody; users should verify its performance in their specific buffer systems.

CamelBio: Your One-Stop Sourcing Bridge

CamelBio provides a comprehensive range of IVD raw materials, including validated antibody pairs, optimized monoclonal and polyclonal antibodies, and bulk ancillary reagents, to support diagnostic manufacturers and research laboratories. Our one-stop sourcing covers critical targets like CD33 for immune monitoring and oncology assay development. Additionally, we offer rare-target raw-material sourcing, technical services, and consulting, streamlining your path from concept to clinic.