Nicotinic environment affects the differentiation and functional maturation of monocytes derived dendritic cells (DCs)

Differentiation of tissue monocytes into DCs is a critical phase in the development of a competent immune system. We show that in a nicotinic environment, while human monocytes differentiate into DCs (henceforth called nicDCs) with a typical morphology, they display unique phenotype and cytokine profile that adversely affect their function. Despite an increased capacity for receptor-dependent antigen uptake, nicDCs do not express CD1a and fail to fully up-regulate MHCs, molecules essential for their antigen-presenting function. Additionally, in response to bacterial antigen LPS, maturing nicDCs hardly express the chemotactic cytokine receptor 7 required for their entry into lymphatic vessels. Furthermore, in parallel with their differential expression of costimulatory molecules CD80 and CD86 and lack of IL-12, nicDCs display profoundly reduced Th1 promoting capacity. These findings thus indicate that nicotine impedes the development of cell-mediated immunity by skewing DC differentiation. These effects of nicotinic environment on DC differentiation may contribute to the increased risks of respiratory tract infection and various cancers in smokers. (C) 2004 Elsevier B.V. All rights reserved.