FIG. 4.

HS chain removal abrogates the anti-HIV activity of the syndecan-Fc hybrid molecule. (A) Blood-derived CD4⁺ T lymphocytes (0.5 × 10⁶ cells) were exposed to JR-CSF (1 ng of p24) and untreated syndecan-1-Fc, heparinase-treated syndecan-1-Fc, or control Fc (5 μg/ml) for 1 day at 37°C and washed. The amount of virus released was monitored by measuring amounts of p24 capsid protein in cell supernatants by ELISA. (B) The same experiment as in panel A was performed except that the Δ3HS-syndecan-1-Fc, which is devoid of its HS chains after mutagenesis of its three glycosaminoglycan attachment sites, was tested for anti-HIV-1 activity. The points are median values, and error bars represent standard errors of triplicates. The P values were calculated using a one-sided t test assuming equal variances.