T-cell receptor Vpexpression innormalhumanskin

Theskin-associated immunesystem isthe first line ofdefense against pathogenic attack fromtheenvi- ronment andissimultaneously tolerant tolocalized autoanti- gensandtoantigens ofthenormal microbial flora. TheT-cell receptor (TCR)repertoire ofskinlymphocytes maytherefore beinfluenced bytheskinmicroenvironment. We studied the expression ofTCR E-chain variable region (Vp) genesin normal skin byapolymerase chain reaction-based comparative method. Whencomparing theamplification ofVpgenesin peripheral blood andnormal skin, wefound that TCRVpl,-7, -14, and-16wereoften highly expressed inskinrelative to peripheral blood, whereas Vp5.1 wasoften highly expressed in peripheral blood mononuclear cells butnotinskin. These results demonstrate that theTCRrepertoire ofskinlympho- cytes isnotdetermined byrandomsampling ofperipheral blood mononuclear cells butmaybemolded bytheinteraction withself antigens and/or thenormalmicrobial flora inthe microenvironment oftheskin. Epithelial organs, suchasintestine andskin, comprise an essential part oftheperipheral immune system. These tissues areexposed toavariety ofenvironmental antigens while supporting adiverse microbial flora. This dual demand onthe immunesystem mayrequire special adaptations oftheresi- dentTlymphocytes tofulfill these functions. Suchaspecial- izedadaptation isfoundinmurine skinandepithelia of