TUMOR-NECROSIS-FACTOR RECEPTOR EXPRESSION IN HIV-1-INFECTED CD4-CELLS( T)

We investigated whether HIV-1 can regulate tumor necrosis factor recep tor (TNFR) expression in SupT-1, a CD4+ T-cell line. The cells were in fected with HIV-1 containing 1,000 cpm RT activity, as early as day 3 after infection and all along the culture the supernatant level of cor e protein p24 was > 250 pg/ml, and on days 6 and 9 after infection, p2 4 was found in 10 % of the cells as determined by indirect immunofluor escence assay. The cells were growing without loss of viability. The s tudy of TNFR expression was based on a microassay for measurement of b inding of I-125-TNF alpha to cells, in which free and cell-bound ligan d separation was performed by centrifugation through oil. Scatchard an alysis of TNF alpha binding on days 6 and 9 after infection revealed a 90 % increase in the expression of high-affinity membrane receptors i n HIV + SupT-1 culture compared with uninfected cells (mean +/- S.D. = 501 +/- 148.5 vs. 263 +/- 77.8 receptors/cell, n = 9, P < 0.001) with no change in dissociation constants (mean +/- S.D. = 4.36 +/- 1.06 vs . 4.00 +/- 1.12 X 10-(10) M).