Constitutive expression of various chemokine genes in human T‐cell lines infected with human T‐cell leukemia virus type 1: Role of the viral transactivator Tax

We examined the genetic expression of 2 CXC chemokines (IL‐8, IP‐10), 5 CC chemokines (MCP‐I, MIP‐Iα, MIP‐Iβ, RANTES, 1309) and I C chemokine (SCM‐I/lymphotactin/ATAC) in various human T‐cell lines. By Northern blot analysis, HTLV‐I‐positive T‐cell lines were found to express a number of chemokine genes at variable levels and in different combinations. However, none of the chemokine genes was expressed in HTLV‐I‐negative T‐cell lines. We further confirmed secretion of 3 chemokines (IL‐8, MIP‐Iα and RANTES) by some HTLV‐I‐positive T‐cell lines. To examine the role of the HTLV‐I‐encoded transactivator Tax in the induction of these chemokine genes, we used JPX‐9 and JPX‐M, which were stably transformed with tax and non‐functional tax, respectively, under the control of a metallothionein promoter. Induction of tax in JPX‐9 with Cd2+ was accompanied by rapid induction of IL‐8, IP‐10, MIP‐Iα, MIP‐Iβ, 1309 and SCM‐I as determined by reverse transcription PCR. No such induction was seen in JPX‐M. We thus suggest that Tax is, at least in part, responsible for constitutive expression of certain chemokine genes in HTLV‐I‐infected T cells. Aberrant production of various chemokines by HTLV‐I‐infected T cells may impact on the pathophysiology of HTLV‐I‐associated diseases. © 1996 Wiley‐Liss, Inc.