**Background of HRG Antibodies**
Histidine-rich glycoprotein (HRG), a plasma protein synthesized primarily in the liver, plays multifaceted roles in regulating immune responses, angiogenesis, coagulation, and apoptosis. Structurally, HRG contains distinct domains, including a histidine/proline-rich region, which mediates interactions with various ligands such as heparan sulfate, fibrinogen, and plasminogen. These interactions enable HRG to modulate biological processes like immune complex clearance, vascular remodeling, and antimicrobial activity.
In disease contexts, HRG exhibits dual roles. In cancer, HRG can suppress tumor progression by inhibiting excessive angiogenesis via neutralization of angiogenic factors (e.g., VEGF) or promote apoptosis in tumor cells. Conversely, HRG deficiency or dysfunction has been linked to thrombotic disorders, inflammatory diseases, and impaired pathogen clearance. HRG antibodies, developed for research and therapeutic purposes, target specific epitopes to either block or enhance HRG's activity. For instance, neutralizing HRG antibodies may augment chemotherapy efficacy by disrupting HRG-mediated survival signals in tumors. Conversely, agonist antibodies might mimic HRG's anti-angiogenic effects.
Research on HRG antibodies remains evolving, with studies exploring their potential in cancer immunotherapy, thrombosis management, and infectious disease. Challenges include optimizing specificity to avoid off-target effects and understanding context-dependent roles of HRG in different pathologies. Overall, HRG antibodies represent a promising tool to therapeutically harness HRG's regulatory functions.