The equine herpesvirus 2 E1 open reading frame encodes a functional chemokine receptor

Several herpesviruses contain open reading frames (ORFs) that encode potent ial homologs of eucaryotic genes. Equine herpesvirus 2 (EHV-2) is a gammahe rpesvirus related to other lymphotropic herpesviruses such as herpesvirus s aimiri and Epstein-Barr virus. The E1 ORF of EHV-2, a G protein-coupled rec eptor homolog, shows 31 to 47% amino acid identity with known CC chemokine receptors. To investigate whether E1 may encode a functional receptor, we c loned the E1 ORF and expressed it in stably transfected cell lines. We repo rt here the identification of the CC chemokine eotaxin as a functional liga nd for the EHV-2 E1 receptor. Chemokines are likely to play a role in the r egulation of immune functions in equine hosts during EHV-2 infection and, v ia interaction with E1, may affect viral replication and/or escape from imm une responses.