Figure 1

Expression of Tax, HBZ-SI, HLA-A*02, ICAM-1 and Fas by HTLV-1 infected primary CD4 ⁺cells. (A-D) Upregulation of HLA-A*02, ICAM-1 and Fas occurs subsequent to the appearance of detectable levels of intracellular Tax protein. Purified CD4⁺ cells from four infected individuals (2 AC, circular symbols; 2 HAM, triangular symbols; two of which were HLA-A*02⁺) were cultured for 0-24 h. Surface molecules were stained with antibodies specific for HLA-A*02, ICAM-1, Fas, and CD4. Subsequently, cells were stained intracellularly with a Tax-specific antibody and analysed by flow cytometry. Values are expressed either as the percentage of CD4⁺ cells within the positive gate or as median fluorescence intensity on CD4⁺ T cells. (E-F) Expression of HBZ-SI and Tax mRNA by infected cells. CD8 depleted PBMC from six donors (2 AC, circular symbols; 4 HAM/TSP, triangular symbols) were incubated for 16 h to allow for Tax expression and ICAM-1 upregulation. Cells were subsequently sorted on the basis of ICAM-1 expression separating Tax⁺ (ICAM-1⁺) from Tax⁻ (ICAM-1^-/low) cells. Exact copy numbers of HBZ-SI mRNA and Tax mRNA were quantified and expressed as number of copies per infected cell in each fraction. Statistics: ICAM⁺ vs. ICAM-1^low/−, Wilcoxon matched pairs test, two tailed. See Additional file 6 for donor characteristics.