Feline Langerhans cells migrate from skin and vaginal mucosa to regional lymph nodes during experimental contact sensitization with fluorescein isothiocyanate

Recently, feline Langerhans cells (LC) were immunophenotypically characterized as CD1a+, CD4+, CD18+, CD53+ and MHC II+ cells. In mice, these cells are known to internalize antigens and to migrate to the lymph nodes (LN). In the cat, we have investigated the migration of LC from the skin and vaginal mucosa to regional LN in response to chemical exposure (fluorescein isothiocyanate). Three days after the administration of a FITC solution on the posterior limb of two male cats and in the vagina of one female, a biopsy was carried out on the draining LN of the sensitized zones. Immunostaining with monoclonal antibodies anti-CD79, anti-CD8, and antibodies recognizing LC was performed on cytospins and frozen sections of LN and showed that a majority of FITC+ cells displayed a LC immunophenotype and were localized in T-cell areas, but not in follicular areas. These results are the first evidence of migration of feline LC from skin and vaginal mucosa to the regional LN.