Mapping the Interaction of Human Albumin with the Invariant Chain

Abstract

Albumin hitchhiking has been applied in the vaccine development by conjugating peptides or adjuvants to an amphipathic lipid that can bind to albumin and thus deliver immunogens and adjuvants to lymph nodes. While many studies have shown that albumin hitchhiking can boost immune responses by increasing antigen-specific CD8+ T cells and enhancing cytolytic activity, the receptor that mediates albumin-hitchhiking to the lymph node had not previously been identified. Our group hypothesized that antigen-presenting cells have a cell-surface receptor for albumin that may function as albumin-hitchhiking receptor and present albumin to B cells, and the lab recently identified the invariant chain (CD74) as the albumin-hitchhiking receptor. To further elucidate the functionality of interaction between these two proteins, I used an immunoprecipitation/western blot approach to validate the HSA-CD74 interaction and identify HSA domain II as the potential determinant of HSA-CD74 interaction.