ABCB9 Antibody

Introduction to ABCB9 and Its Antibody

ABCB9 (UniProt ID: Q9NP78) is an ATP-dependent transporter that translocates cytosolic peptides into lysosomes for degradation, with roles in antigen presentation and lysosomal function . Antibodies against ABCB9 are primarily used to study its expression, localization, and biological roles in diseases such as cancer . These antibodies are typically polyclonal, raised in rabbits, and validated for applications including Western blot (WB), immunohistochemistry (IHC), and immunoprecipitation (IP) .

Table 1: Comparison of Select ABCB9 Antibodies

• Host/Isotype: All commercial ABCB9 antibodies are rabbit-derived IgG .

• Dilution Ranges:

  • WB: 1:500–1:2000

  • IHC: 1:50–1:500

(A) Functional Insights

• ABCB9 transports peptides 6–59 amino acids long, favoring hydrophobic/aromatic residues .

• Linked to MHC class I/II antigen presentation pathways due to lysosomal localization in dendritic cells .

(C) Technical Challenges

• A polyclonal ABCB9 antibody (Abcam 86222) showed cross-reactivity with an unidentified 84 kDa protein in ABCB9-knockout cells, highlighting specificity risks .

Critical Considerations for Use

• Validation Requirements:

  • Include knockout controls (e.g., ABCB9-deficient cell lysates) to confirm specificity .

  • Optimize antigen retrieval methods (e.g., TE buffer pH 9.0 for IHC) .

• Molecular Weight Discrepancies: Observed bands may migrate at 72 kDa (vs predicted 84 kDa) due to post-translational modifications .

Future Research Directions

• Investigate ABCB9’s role in chemotherapy resistance, given its homology to multidrug resistance (MDR) transporters .

• Develop monoclonal antibodies to address polyclonal cross-reactivity limitations .