The ability of human keratinocytes to present antigen to T cells is controversial and, indeed, it has been suggested that keratinocytes may promote T cell hyporesponsiveness. Furthermore, it is unclear whether keratinocytes can process antigen prior to MHC class I and class II presentation. We tested the ability of keratinocytes to induce functional responses in epitope-specific CD4 + and CD8 + memory T cells using peptides, protein and recombinant expression vectors as sources of antigen. Keratinocytes were able to efficiently process and present protein antigen to CD4 + T cells, resulting in cytokine secretion (Th1 and Th2). This interaction was dependent on keratinocyte expression of HLA class II and ICAM-1, which could be induced by IFN-c. In addition, keratinocytes could present virally encoded or exogenous peptide to CD8 + T cells, resulting in T cell cytokine production and target cell lysis. Finally, T cell lines grown using keratinocytes as stimulators showed no loss of function. These findings demonstrate that keratinocytes are able to efficiently process and present antigen to CD4 + and CD8 + memory T cells and induce functional responses. The findings have broad implications for the pathogenesis of cutaneous disease and for transcutaneous drug or vaccine delivery.

We have demonstrated that in > 40% of our vulval LS and LP patients, the NC16A domain of BP180 is a target for circulating T cells, and in vulval LS and LP there are associated autoantibodies to BP180.