Stable TatIII cell lines, TatIII gene products, and assay methods

Abstract

This invention describes stable tat.sub.III cell lines. It is disclosed that by transfecting a preselected tat.sub.III cell line with a vector containing a sufficient amount of the HTLV-III LTR responsive to tat.sub.III gene products for trans-activation and an enhancer upstream of the tat.sub.III responsive segment, it is possible to express high levels of the tat.sub.III gene products. By including a preselected heterologous gene on this vector, it is also possible to express high levels of a desired gene product. A substantially pure protein comprising 86 amino acids and having an apparent molecular weight of about 14,000 dalton and exhibiting trans-activating activity is also disclosed. This protein and polypeptides having trans-activating ability, which is also disclosed, can be used to produce high levels of a desired gene product. A method of detecting the presence of HTLV-III/LAV virus in an individual is also disclosed and comprises the step of: (a) incubating whole blood or lymphocytes from the invididual to be tested with tat.sub.III cell lines of the present invention in a culture medium; and (b) screening for cytopathic effects on the cells is also disclosed. A method of screening for a compound that inhibits trans-activation of the tat.sub.III gene product is also disclosed and comprises the steps of: (1) transacting a tat.sub.III cell line of the present invention with a vector containing a gene that expresses a selectable marker and whose expression is under the control of an HTLV-III LTR; (2) transfecting the same type of tat.sub.III cell lines as in step (1) with the selectable gene chosen in step (1) but under the control of a different regulatory sequence; (3) thereafter, adding a preselected compound to each of the cell lines in increasing concentrations; and (4) measuring the expression of the selectable gene product to determine whether the compound effects the tat.sub.III function without being toxic to the cell.

Dependencies are inferred from the claim text.