Exploiting albumin as a mucosal vaccine chaperone for robust generation of lung-resident memory T cells.

Tissue-resident memory T cells (TRMs) can profoundly enhance mucosal immunity, but parameters governing TRM induction by vaccination remain poorly understood. Here, we describe an approach exploiting natural albumin transport across the airway epithelium to enhance mucosal TRM generation by vaccination. Pulmonary immunization with albumin-binding amphiphile conjugates of peptide antigens and CpG adjuvant (amph-vaccines) increased vaccine accumulation in the lung and mediastinal lymph nodes (MLNs). Amph-vaccines prolonged antigen presentation in MLNs over 2 weeks, leading to 25-fold increased lung-resident T cell responses over traditional immunization and enhanced protection from viral or tumor challenge. Mimicking such prolonged exposure through repeated administration of soluble vaccine revealed that persistence of both antigen and adjuvant was critical for optimal TRM induction, mediated through T cell priming in MLNs after prime, and directly in the lung tissue after boost. Thus, vaccine persistence strongly promotes TRM induction, and amph-conjugates may provide a practical approach to achieve such kinetics in mucosal vaccines.