HUMAN T-CELL LEUKEMIA-VIRUS TYPE-1 TAX PROTEIN INDUCES THE EXPRESSIONOF LYMPHOCYTE CHEMOATTRACTANT SDF-1 PBSF/

We investigated the mechanism of lymphocyte infiltration into tissues infected with human T-cell leukemia virus type 1 (HTLV-1). The cytokin e SDF-1/PBSF is a highly efficient chemoattractant for lymphocytes. Re verse transcription-PCR analysis showed that among various human T-cel l lines, those infected with HTLV-1 selectively expressed the SDF-1 ge ne. Expression of the viral protein Tax in a human T-cell line induced the expression of the SDF-1 gene, indicating that the constitutive ex pression of SDF-1 in virus-infected cell lines is at least in part med iated by Tax. HTLV-1-infected T-cell lines also expressed CXCR-4, a re ceptor for SDF-1. Moreover, chemotaxis assay showed that a HTLV-1-infe cted cell line migrated toward synthetic SDF-1. Thus, HTLV-1-infected cells are themselves responders for SDF-1. Our results suggest that SD F-1 induced by Tax may alter the distribution of HTLV-1-infected cells in vivo; hence it may contribute to their infiltration into affected tissues in HTLV-1-associated inflammatory diseases. (C) 1998 Academic Press.