Human T-Cell Leukemia Virus Type 1 Tax Protein Induces the Expression of Lymphocyte Chemoattractant SDF-1/PBSF

AbstractWe investigated the mechanism of lymphocyte infiltration into tissues infected with human T-cell leukemia virus type 1 (HTLV-1). The cytokine SDF-1/PBSF is a highly efficient chemoattractant for lymphocytes. Reverse transcription–PCR analysis showed that among various human T-cell lines, those infected with HTLV-1 selectively expressed theSDF-1gene. Expression of the viral protein Tax in a human T-cell line induced the expression of theSDF-1gene, indicating that the constitutive expression ofSDF-1in virus-infected cell lines is at least in part mediated by Tax. HTLV-1-infected T-cell lines also expressed CXCR-4, a receptor for SDF-1. Moreover, chemotaxis assay showed that a HTLV-1-infected cell line migrated toward synthetic SDF-1. Thus, HTLV-1-infected cells are themselves responders for SDF-1. Our results suggest that SDF-1 induced by Tax may alter the distribution of HTLV-1-infected cellsin vivo;hence it may contribute to their infiltration into affected tissues in HTLV-1-associated inflammatory diseases