IDENTIFICATION OF HTLV-I-PRODUCING OR HTLV-II-PRODUCING CELLS BY COCULTIVATION WITH BHK-21-CELLS STABLY TRANSFECTED WITH A LTR-LACZ GENE CONSTRUCT

The Syrian Hamster kidney cell line (BHK-21) was stably transfected wi th a plasmid vector containing the lacZ bacterial gene under the contr ol of a HTLV-I-LTR promoter. In these cells termed pA18G-BHK-21, this lacZ construct is inducible by the tax protein produced by a tax expre ssion vector. It was also shown that beta-galactosidase synthesis was detected within 48 h after cocultivation of pA18G-BHK-21 cells with HT LV-I (HUT-102, MT2, C91/PL, 2060) or HTLV-II (MoT strain) -producing c ells. The number of positive cells was directly related to the number of HTLV-I or -II-infected cells seeded. In addition, the LTR transacti vation observed in coculture with HTLV-I-infected cells was specifical ly inhibited by sera containing antibodies directed against HTLV-I pro teins, but not, or only weakly, by sera containing HTLV-II antibodies. Conversely, beta-galactosidase expression induced by HTLV-II-infected cells was inhibited by sera of HTLV-II-infected individuals, but not, or only weakly, by HTLV-I-positive sera. Irrespective of the inducer cell, sera from uninfected people did not inhibit LTR-driven expressio n of the lacZ gene in pA18G-BHK-21 cells cocultivated with HTLV-produc ing cells. This assay may thus be employed profitably for the detectio n and quantification of both HTLV-producing cells and HTLV-specific an tibodies.