Blocking pathogenic anti-donor antibody responses

About This Grant

PROJECT SUMMARY This proposal outlines a three-year training plan focused on developing antibody-based therapies that address transplant rejection driven by donor-specific antibodies (DSAs). DSAs recognize mismatched human leukocyte antigens (HLAs) on transplanted organs, leading to antibody-mediated rejection (AMR) through complement activation, inflammation and graft destruction. Among HLAs, HLA-DQ mismatches are a major driver of DSA formation and transplant rejection, yet current treatments fail to target them precisely. Current treatment strategies such as plasmapheresis and B cell depletion (e.g., Rituximab) reduce all antibodies (Abs), including DSAs, but fail to specifically target the underlying cause—mismatched HLA-DQ. Other immunosuppressants, such as calcineurin and T cell co-stimulation inhibitors, aim to reduce de novo DSA formation but are ineffective in patients with pre-existing DSAs. The key limitation is their reliance on global immunosuppression rather than precise targeting and lack of applicability to patients with pre-existing DSAs. To address these limitations, we propose a novel strategy using anti-donor HLA-DQ-specific B cell receptor (BCR) libraries to repurpose pathogenic DSAs as allograft-protective Abs. We hypothesize that we can engineer recombinant Abs (rAbs) from pathogenic DSAs into potent blocking Abs of DSA-mediated allograft damage, offering treatment for patients with or without pre-existing DSAs. In aim 1, we will first map and confirm the epitopes of anti-HLA-DQ Abs. Using a yeast displayed library, we will conduct high-throughput epitope characterization and assess cross-reactivity with different HLA-DQ alleles. Structural analysis through cryo-electron microscopy (cryo-EM) will validate these interactions. In aim 2, we will design and test Fc-silenced anti-HLA-DQ rAbs to prevent complement activation and Fc-mediated effects. We will test multiple Fc silencing modifications to achieve potent silencing. In aim 3, we will test the efficacy of anti-HLA-DQ rAbs in blocking serum DSAs. We will compare a cocktail of rAbs and bi-paratopic rAbs to determine maximal coverage of HLA-DQ polymorphic sites. We hypothesize that bi-paratopic rAbs will be more effective due to enhanced avidity. This project seeks to develop a targeted immune therapy that mitigates DSA-mediated transplant rejection, without relying on broad immunosuppression, addressing an unmet clinical need. Under the sponsorship of Drs. Habal and Koide—experts in transplant rejection and protein engineering—I will get training in key technical skills, such as single-cell sorting and single-B cell culture, and engineering Fc-silenced rAbs. With access to extensive resources available at NYULH, I will enhance my scientific expertise, develop new technical competencies, and advance my professional growth. These experiences will prepare me to transition into an independent investigator developing protein-based therapies for immune-mediated diseases.