1These authors contribute equally.
Effects of phthalate esters on the sensitization phase of contact hypersensitivity induced by fluorescein isothiocyanate
Article first published online: 2 NOV 2006
Clinical & Experimental Allergy
Volume 36, Issue 11, pages 1462–1468, November 2006
How to Cite
Imai, Y., Kondo, A., Iizuka, H., Maruyama, T. and Kurohane, K. (2006), Effects of phthalate esters on the sensitization phase of contact hypersensitivity induced by fluorescein isothiocyanate. Clinical & Experimental Allergy, 36: 1462–1468. doi: 10.1111/j.1365-2222.2006.02574.x
- Issue published online: 2 NOV 2006
- Article first published online: 2 NOV 2006
- Submitted 23 June 2005; revised 25 July 2006; accepted 11 August 2006
- contact sensitivity;
- DC trafficking;
- di-butyl phthalate;
- draining lymph nodes;
Background Many different types of phthalate ester are used as plasticizers and are thus found in the air. There have been several studies that suggest an association between allergies and phthalate esters. We previously found that di-butyl phthalate (DBP) has an adjuvant effect in a mouse contact hypersensitivity model, in which fluorescein isothiocyanate (FITC) is involved as an immunogenic hapten.
Objective We examined whether other phthalate esters enhance the process of sensitization to FITC by facilitating the trafficking of FITC-presenting dendritic cells or macrophages from skin sites to draining lymph nodes.
Methods Mice were epicutaneously sensitized with FITC dissolved in acetone containing a phthalate ester. Sensitization was evaluated as ear swelling after a challenge with FITC. Draining lymph node cells obtained 24 h after skin sensitization were examined for FITC fluorescence by means of flow cytometry. FITC-positive cells were characterized with anti-CD11c and anti-CD11b by three-colour flow cytometry.
Results When mice were sensitized with FITC in acetone containing DBP or di-n-propyl phthalate (DPP), strong enhancement of the ear-swelling response was observed. Di-methyl phthalate (DMP) and di-ethyl phthalate (DEP) were less effective but produced some enhancement. Consistent enhancement was not observed with di-(2-ethylhexyl) phthalate or di-isononyl phthalate. Upon sensitization in the presence of DBP or DPP, the number of FITC-positive dendritic cells (total CD11c+ as well as CD11c+/CD11b+) was increased in draining lymph nodes. As to the other four phthalate esters, there was no significant increase in the FITC-positive cell number in the draining lymph nodes.
Conclusion During the process of sensitization to FITC, DBP, and DPP exert strong adjuvant effects that are associated with enhancement of trafficking of antigen-presenting dendritic cells from the skin to draining lymph nodes.