Assistant Professor Boston Children's Hosp., Harvard Med. Sch., United States
Disclosure(s):
Novalia Pishesha, PhD: No financial relationships to disclose
Introduction/Rationale: Current treatments for autoimmunity and allergy manage symptoms rather than cure disease. We propose a curative nanobody-based approach that selectively silences pathogenic responses to specific antigens/allergens while preserving protective immunity, i.e., durable antigen-specific immune tolerance. We also developed nanobody tools to map antigen processing and T cell responses in vivo, enabling precise visualization and quantification of tolerance induction at the molecular and cellular levels.
Methods: We developed an engineering-based solution using alpaca-derived nanobodies (VHHs) that recognize all MHC class II molecules (VHH MHCII). We covalently conjugated disease- or allergen-specific peptides-derived from myelin, insulin, and citrullinated collagen, as well as the model antigen ovalbumin (OVA) and house dust mite allergen to VHH MHCII together with the anti-inflammatory drug dexamethasone (VHH MHCII-antigen-DEX).
Results: A single dose of these trimodal conjugates induced durable, antigen-specific tolerance by promoting deletion, anergy, and regulatory differentiation of antigen-specific T cells. VHH MHCII-Myelin-DEX reversed experimental autoimmune encephalomyelitis, VHH MHCII-collagen-DEX halted arthritis progression, and intranasal delivery of VHH MHCII-OVA-DEX reduced OVA-specific IgG/IgE, mast cell activation, and airway inflammation.
Conclusion: This approach imposed long-lasting tolerance in prophylactic and therapeutic settings while maintaining systemic heterotypic immunity. Complemented by newly developed anti-idiotypic nanobodies specific for myelin- and OVA-specific TCRs, functionalized for fluorescence and positron emission tomography (PET) imaging, we achieved real-time visualization of antigen processing and tolerance induction. Together, these tools reveal how APC networks orchestrate tolerance and establish a modular platform for antigen- and allergen-specific immunotherapy. The available human-specific version of VHH MHCII enables translation to a clinical setting.
