Department of Dermatology University Muenster - Germany

Transgenic mouse model
In this sub-project we are trying to establish an animal model for polymorphic light eruption (PLE). Since there are human data that PLE may be due to an alteration of the migration behaviour of Langerhans cells we are trying to generate transgenic mice in which the migration pattern of Langerhans cells is altered. High overexpression of the costimulatory molecule CD40 ligand (CD40L) in the epidermis activates Langerhans cells which ultimately leave the skin. These mice develop spontaneously an inflammatory skin phenotype and systemic autoimmunity. We have generated a transgenic mouse which overexpresses CD40L at lower levels in the epidermis. These mice do not develop a spontaneous inflammatory skin phenotype. We are testing whether we can induce an inflammatory reaction by chronic UVB and UVA exposure, respectively. In turn we are using mice which are deficient in the expression of CD40. It is known that due to the lack of the expression of this costimulatory molecule Langerhans cells do not emigrate out of the skin. These mice will be exposed chronically to both UVA and UVB and we will determine whether these mice will develop an inflammatory skin phenotype resembling PLE.