Olea europaea pollen lipids activate invariant natural killer T cells by upregulating CD1d expression on dendritic cells - 29/04/13
Corresponding author: Eduardo Martínez-Naves, PhD, Unidad de Inmunología, Facultad de Medicina, Universidad Complutense, Avda Complutense s/n, 28040 Madrid, Spain.Abstract |
Background |
Invariant natural killer T (iNKT) cells recognize lipids presented by CD1d and have been implicated in the pathogenesis of allergic asthma. Recognition of plant pollen lipids by iNKT cells and their role in allergic responses are poorly defined.
Objective |
Our goal was to investigate whether iNKT cells can be activated by monocyte-derived dendritic cells (DCs) exposed to lipid antigens from Olea europaea.
Methods |
DCs generated in vitro were exposed to O europaea pollen grains or lipids isolated from them. Expression of lipid-presenting molecules (CD1), as well as maturation markers (HLA-DR, HLA-I, CD86, and CD80 molecules), on DCs was analyzed. iNKT cell activation after coculture with DCs was evaluated based on expansion, cytokine production, and cytotoxicity tests.
Results |
DCs upregulated CD1d and CD86 expression and downregulated CD1a expression after exposure to a whole extract of olive pollen lipids. CD1d and CD1a were regulated at the transcriptional level in a peroxisome proliferator-activated receptor γ activation–dependent manner. Polar lipids, diacylglycerols, free fatty acids, and triacylglycerols isolated from pollen grains upregulate CD1d. The increase in CD1d expression on the DC cell surface induced by polar lipids was not regulated at the RNA level. iNKT cells efficiently recognize DCs treated with the different lipids isolated from olive pollen grains.
Conclusions |
Lipids from O europaea pollen upregulate CD1d and CD86 molecules on DCs, which are then able to activate iNKT cells through a CD1d-dependent pathway.
Le texte complet de cet article est disponible en PDF.Key words : Pollen lipids, Olea europaea, dendritic cells, invariant natural killer T cells, CD1d, peroxisome proliferator-activated receptor γ
Abbreviations used : DC, FFA, iDC, iNKT, PPARγ
Plan
| Supported by grants from Spanish Ministerio de Sanidad (reference FIS-PI080125) and Universidad Complutense de Madrid (reference 920631, to E.M.-N.). B.A.-G. is the recipient of a predoctoral fellowship from Universidad Complutense de Madrid. |
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| Disclosure of potential conflict of interest: B. Abós-Gracia, M. G. del Moral, J. López-Relaño, V. Viana-Huete, and E. Martinez-Naves have received one or more grants from and support for travel from the Spanish Ministry of Health. The rest of the authors declare that they have no relevant conflicts of interest. |
Vol 131 - N° 5
P. 1393 - mai 2013 Retour au numéro
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