LILRB5 Antibody

Antibody Characterization and Applications

The AF3065 antibody (R&D Systems) is a goat polyclonal antibody targeting human LILRB5/CD85c/LIR-8. Key features include:

• Target Epitope: Extracellular domain (Arg18-His456) of LILRB5 .

• Molecular Weight: Detects ~64 kDa protein in western blot .

• Applications:

  • Flow cytometry (e.g., detecting LILRB5 on human peripheral blood monocytes) .

  • Western blot (e.g., identifying LILRB5 in bone marrow lysates) .

  • Co-immunoprecipitation (e.g., confirming LILRB5–HLA class I interactions) .

Ligand Specificity

LILRB5 binds HLA class I free heavy chains (FHCs), unlike other LILRs that require β2-microglobulin (β2m)-associated HLA I . Key interactions include:

Cellular Expression

• Primary Sites: Monocytes, dendritic cells (DCs), and CD8+ T cells .

• Regulation:

  • Upregulated in monocyte-derived DCs after Mycobacterium bovis exposure .

  • Induced on cytotoxic T cells during mycobacterial infection .

Inhibitory Signaling

• LILRB5 contains immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that suppress immune activation .

• Mechanism: Binds HLA class I FHCs to inhibit antigen presentation and T cell activation .

Pro-Inflammatory Effects

• CD8+ T Cell Proliferation: Crosslinking LILRB5 with antibodies enhances cytotoxic T cell proliferation (p = 0.0049) .

• Mycobacterial Response:

  • Facilitates recognition of Mycobacterium tuberculosis .

  • May counteract immune evasion by pathogens .

Key Studies Using LILRB5 Antibodies

1. HLA-Class I Interaction (Zhang et al., 2015):

   • Demonstrated LILRB5 binds HLA-B27 FHCs using AF3065 for FACS and co-IP .

2. Mycobacterial Immunity (PMC, 2016):

   • Identified LILRB5 upregulation in DCs post-BCG vaccination .

3. T Cell Modulation (Frontiers, 2021):

   • Linked LILRB5 ligation to CD8+ T cell proliferation during infection .

Technical Considerations

• Cross-Reactivity: ~20% with recombinant human LILRB1 .

• Storage: Stable at -70°C; reconstituted aliquots viable for 6 months .

• Limitations:

  • Variable detection on lymphocytes (e.g., T cells vs. monocytes) .

  • Heat-killed mycobacteria reduce ligand binding affinity .

Therapeutic Implications

LILRB5 antibodies are being explored for:

• Cancer: Blocking immunosuppressive interactions in myeloid-derived suppressor cells (MDSCs) .

• Infectious Diseases: Enhancing anti-mycobacterial CD8+ T cell responses .