Immunological memory in humans

Specificity and memory are the defining characteristics of adaptive immune responses. Vaccines are predicated on the existence of immune memory, and the robustness of immune memory is a primary determinant of vaccine efficacy. How is immune memory maintained? Much progress has been made in this area over the past several years, and new human studies have added key insights into the longevity of B and T cell immune memory in the absence of antigen. (C) 2004 Elsevier Ltd. All rights reserved.