Figure 5.

The human immunodeficiency virus 1 (HIV-1) envelope glycoprotein gp120 inhibits the adenosine deaminase (ADA)-induced costimulatory effect. (a) Proliferation of unstimulated (white columns), 1 ng/ml anti-CD3-stimulated (grey columns) or 1 ng/ml anti-CD3 plus 4 μm ADA-stimulated (black columns) T cells obtained from a healthy donor was determined in the absence or presence of 100 nm HIV-1 gp120 (gp120) or 100 nm HIV-1 Gag (gag) as a control. [³H]Thymidine incorporation was measured after 6 days of culture and expressed as the stimulation index (SI), calculated as the ratio of [3H] thymidine incorporated in stimulated T cells versus non-stimulated T cells. One representative experiment of nine with different donors is shown and data are the mean ± standard deviation of triplicates. (b) Cytokine secretion of T cells stimulated with 1 ng/ml anti-CD3 (light grey columns), or with 1 ng/ml anti-CD3 plus 4 μm ADA in the absence of gp120 (black columns) or in the presence of 100 nm gp120 (dark grey columns) was determined as indicated in the Materials and methods. One representative experiment of five with different donors is shown and data are the mean ± standard deviation of triplicates. *P < 0·05; **P< 0·01; ***P < 0·001; ns, not significant, by paired Student’s t-test.