The role of CD4+ T cells in the induction of contact hypersensitivity to mercury in a murine model.

Abstract

BACKGROUND: The exact immunopathogenesis of contact hypersensitivity (CH) to mercury remains unclear. OBJECTIVE: The aim of the present study was to assess the role of CD4+ T cells in mercury-induced CH in mice. METHODS: Splenic CD4+ T cells obtained from nonsensitized and mercury-sensitized Balb/c mice were adoptively transferred to groups I and II of the syngeneic recipients, respectively. All recipients were ear-challenged with mercury. The next experiments were to transfer nonsensitized CD4+ T cells to group A of the recipients, whereas mercury-sensitized CD4+ T cells were transferred to groups B and C. Groups A and B were ear-challenged with mercury, whereas group C was ear-challenged with chromium. The ear swelling 24 hours and 48 hours after challenge was used to assess CH. RESULTS: The results of the present study showed that mercury-sensitized but not nonsensitized CD4+ T cells could transfer CH in mice. Furthermore, mercury-sensitized CD4+ T cells could transfer the induction of CH only in the recipients that were challenged with mercury, but not those that were challenged with chromium. CONCLUSION: The results of the present study suggest that mercury-induced CH may be mediated by mercury-specific CD4+ T cells.