The murine (C3H/He) epidermal Ia+ dendritic cells (Ia+DECs) and Thy-1+ dendritic cells (Thy-1+DECs) in contact hypersensitivity and aging.

The contact sensitivity evaluated by the ear swelling test and the dynamic changes of epidermal Ia+ dendritic cells (Ia+DECs) and Thy-1+ dendritic cells (Thy-1+DECs) were studied in trinitrochlorobenzene (TNCB) sensitized different age group C3H/He mice after challenge. A significant increase of ear swelling was observed between 6 h and 10 days of both 8-10 week (wk) and 40-48 wk groups; the ear swelling indices of 8-10 wk group were significantly higher than those of 40-48 wk group from 18 h to 5 days. A significant decrease of the densities of Ia+DECs from 18 h to 48 h, followed by a gradual increase reaching significant increase of the densities of Ia+DECs from 5 days to 21 days in both 8-10 wk and 40-48 wk groups, was observed; the densities of Thy-1+DECs significantly decreased from 18-48 h, followed by a gradual increase reaching a significant increase from 5 days to 21 days in both 8-10 wk and 40-48 wk groups. In the normal control groups, a significant decline of both Ia+DECs and Thy-1+DECs in the 40-48 wk group was observed. Results suggest that contact allergy may be diminished in aged mice. On the other hand, like Ia+DECs, Thy-1+DECs seem to be involved in the process of contact allergy.