Adjuvant Depot Effect: Chemotaxis & Immune Cell Recruitment

Every injected vaccine starts as a physical depot of antigen at the injection site, and what happens to that depot over the next hours determines how strong the resulting immune priming will be. This simulator models antigen particles diffusing and decaying from an intramuscular depot under real Brownian-motion and first-order-clearance dynamics, and shows how an adjuvant slows both processes — the mechanistic "depot effect" behind why adjuvanted vaccines work better than antigen alone. Innate immune cells are recruited from the local vasculature and chemotax up the antigen gradient toward the depot; cells that capture enough antigen become primed and traffic toward the draining lymph node, where adaptive immune priming actually begins. Adjust adjuvant strength, antigen dose and chemotactic sensitivity and watch how a stronger, longer-lived depot signal recruits more cells and builds a bigger cumulative priming signal.