¹Departamento de Inmunología y Oncología, Centro Nacional de Biotecnología, Universidad Autónoma, Madrid, Spain

Correspondence: Dr Carlos Ardavín, Departamento de Inmunología y Oncología, Centro Nacional de Biotecnología, Universidad Autónoma, Madrid 28049, Spain. E-mail: ardavin@cnb.csic.es

Received 10 February 2008; Accepted 20 February 2008; Published online 25 March 2008.

Abstract

Monocytes have been classically considered essential elements in relation with innate immune responses against pathogens, and inflammatory processes caused by external aggressions, infection and autoimmune disease. However, although their potential to differentiate into dendritic cells (DCs) was discovered 14 years ago, their functional relevance with regard to adaptive immune responses has only been uncovered very recently. Studies performed over the last years have revealed that monocyte-derived DCs play an important role in innate and adaptive immunity, due to their microbicidal potential, capacity to stimulate CD4⁺ and CD8⁺ T-cell responses and ability to regulate Immunoglobulin production by B cells. In addition, monocyte-derived DCs not only constitute a subset of DCs formed at inflammatory foci, as previously thought, but also comprise different subsets of DCs located in antigen capture areas, such as the skin and the intestinal, respiratory and reproductive tracts.