The adaptive immune system is a subsystem of the overall immune system that is composed of highly specialized, systemic cells and processes that eliminate or prevent pathogen growth. Adaptive immunity creates immunological memory after an initial response to a specific pathogen, and leads to an enhanced response to subsequent encounters with that pathogen. This process of acquired immunity is the basis of vaccination.

Introduction to Adaptive Immunity
HUMORAL IMMUNITY
CELL-MEDIATED IMMUNITY
IMMUNODEFICIENCY