Abstract
Development of contact hypersensitivity in mice depends on the migration of Langerhans cells from the epidermis to regional lymph nodes. Since ICAM-1 and LFA-1 play important roles in leukocyte migration, we sought to determine whether in vivo administration of anti-ICAM-1 and anti-LFA-1 antibodies would inhibit contact sensitization-induced migration of epidermal Langerhans cells to regional lymph nodes. Twenty-four hours after contact sensitization of mice with FITC, a brightly FITC-stained Ia + population of dendritic cells capable of stimulating a FITC-specific Ia-restricted T-cell hybridoma was readily detected in their draining lymph nodes. Animals treated with anti-Ia mAb, which depletes Ia + cells in lymph nodes and spleen but not Ia + Langerhans cells in the epidermis, had normal numbers of FITC-bearing Ia + cells capable of stimulating the T-cell hybridoma. Dendritic lymph node cells from mice treated with anti-ICAM-1 and anti-LFA- 1 mAb were devoid of brightly FITC-stained cells and cells capable of stimulating the FITC-specific T-cell hybridoma. The combination of anti-ICAM-1 and anti-LFA-1 mAb completely inhibited the induction of contact hypersensitivity to FITC. Animals treated with anti-ICAM-1 or anti-LFA-1 monoclonal antibodies alone had significantly reduced (by 79 and 36%, respectively) numbers of brightly stained cells capable of stimulating the hybridomas. These data suggest that the adhesion molecules, ICAM-1 and LFA-1, play a significant role in contact hypersensitivity-induced migration of Langerhans cells to regional lymph nodes. The immunomodulatory effects of anti-adhesion molecule antibodies in vivo may be in part due to their effects on antigen-presenting cell migration.
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