Expression of cutaneous lymphocyte-associated antigen by CD8+ T cells specific for a skin-tropic virus

Virus-specific CD8(+) T cells traffic to infected tissues to promote clearance of infection. We used herpes simplex virus type 2 (HSV-2) as a model system to investigate CD8(+) T cell trafficking to the skin in humans. Using human leukocyte antigen (HLA) class I tetramers, we observed that HSV-specific CD8(+) T cells in the peripheral blood expressed high levels of cutaneous lymphocyte-associated antigen (CLA). In contrast, CD8(+) T cells specific for non-skin-tropic herpesviruses lacked CLA expression. CLA-positive HSV-2-specific CD8(+) T cells had the characteristics of central memory cells, expressing CCR7, CD62L, and CD28, and they proliferated briskly in response to antigen. CLA is related to a functional E-selectin ligand, and both E-selectin and CLA-positive cells were detected in HSV-2-infected skin. HSV-2-specific T cells adhered to cells transfected with E-selectin. A higher proportion of HSV-specific CD8(+) T cells recovered from herpes lesions express CLA compared with blood, consistent with a role for CLA in skin homing. To our knowledge, this is the first report of expression of tissue-specific adhesion-associated molecules by virus-specific CD8(+) T cells. The evaluation of vaccines for skin and mucosal pathogens should include study of the induction of appropriate tissue-specific homing molecules.