Therapeutic application of T cell receptor mimic peptides or cDNA in the treatment of T cell-mediated skin diseases.

An 8-amino acid peptide encoding a sequence of the transmembrane region of the T cell receptor alpha chain (TCR-alpha) was shown to inhibit T cell function by preventing functional assembly of the T cell receptor (mimic peptide). To avoid systemic immunosuppression by peptide application in vivo, we used a topical application of the peptide. In the system of murine contact sensitivity, topical application of the peptide inhibited the elicitation of contact sensitivity following application of a contact allergen in sensitized animals. Alternatively, when naked DNA encoding the peptide sequence was injected into skin before application of a contact allergen to sensitized animals, local immunosuppression was also observed. To investigate the effects of this peptide in humans, patients with psoriasis, atopic eczema, lichen planus, or contact dermatitis were treated topically with mimic peptide or control peptide. All patients except for one reported a marked improvement or cure of their skin disease following application of the TCR-alpha peptide, but not controls. These data indicate that TCR-alpha peptide or cDNA treatment might be a proper treatment for human T cell-mediated dermatoses substituting for corticosteroids.