Abstract:
HTLV-I is a human retrovirus associated with Adult T-cell leukemia and a viral-encoded protein, tax, is the potential transforming agent of this virus. The focus of this dissertation is the characterization of this very important viral regulatory protein. In the first part of the thesis a molecular biological approach was used to produce large quantities of a portion of tax. The C-terminal sequences of the tax protein were subcloned in the expression vector pJLA16. The expressed protein was purified and used to raise a rabbit polyclonal antiserum. This antiserum was shown to specifically recognize tax by both immunofluorescence and by radioimmunoprecipitation assay. The bacterially expressed protein was also used as an antigen for serologic studies to identify tax antibodies in HTLV-I positive human sera. These studies showed that the recombinant peptide is immunoreactive with approx 62% of sera from HTLV-I infected individuals (asymptomatic or leukemic). In the second part of the thesis, tax antibodies, raised against the recombinant peptide, were used to examine the expression of the tax protein during in vitro infection of human lymphocytes to determine any critical link between early tax expression and establishment of transformation by HTLV-I. HTLV-I infections of human lymphocytes were performed either with cell-free virions or by co-cultivation. The results obtained indicate that infection by cell free virions does not result in transformation of cells. Viral entry of virions particles into infected lymphocytes was shown to occur, but no expression of viral protein was detected and the cells did not become immortalized. Infections of lymphocytes by co-cultivation resulted in the transformation of lymphocytes 62% of the time. Tax expression in infected lymphocytes was detectable as early as 2 wk from infection, and increased with time in culture. However, expression of tax alone, the putative transforming agent of HTLV-I, is not sufficient to cause transformation, since at least three of the infected lymphocytes samples expressing tax, at early times during infection, failed to become immortalized. Four HTLV-I transformed cell lines were established in the course of these infection studies. These cell lines show the characteristic phenotype of HTLV-I transformed cells T3+, T4+, T8- and Tac+. They all contain at least one integrated copy or more of the proviral genome, and express viral mRNAs and proteins. (Full text available from University Microfilms International, Ann Arbor, MI, as Order No. AAD91-01323).
Keywords: Cell Transformation, Viral Gene Products, tax/*ANALYSIS/GENETICS/IMMUNOLOGY Human HTLV-I/*ANALYSIS Lymphocytes/MICROBIOLOGY THESIS 910930
M9190733
AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.
Important note: Information in this article was accurate in 1991. The state of the art may have changed since the publication date.
