[The role of the HTLV-I virus in transformation of T lymphocytes]

HTLV-I virus is as etiological agent of adult T-cell leukemia (ATL). The virus encodes Tax regulatory protein, which induces malignant transformation of the T lymphocytes. Tax increases the expression of cell protooncogenes as well as lymphokines, among others IL-2 and its receptor. This protein induces autocrine proliferation of T lymphocytes, which is probably the main cause of their transformation. Tax represses the human beta-polymerase gene enzyme involved in host cell DNA repair, and then irreversible damage is effected in the T lymphocyte genome. Moreover, this regulatory protein cooperates with Rex phosphoprotein, stabilizing cell mRNA, which originate as the result of Tax protein activity. The regulatory proteins of HTLV-I virus influence the transcription of some cell genes and their products and in this way induce malignant transformation.