Objectives: We examined the effect and time of addition of beta-chemokines on human immunodeficiency virus type 1 (HIV-1) replication, binding, and uncoating in human macrophages and measured CCR5 receptor expression during virus binding and uncoating.
Methods: Macrophages were treated with beta-chemokines before infection, at infection, or postinfection, and virus replication was determined by p24 antigen level. Binding and uncoating of 35[S]-methionine-labeled HIV-1 was measured. CCR5 expression was determined by flow cytometry.
Results: The beta-chemokines potently inhibited virus replication. The strongest inhibition occurred when cultures were pretreated and maintained with beta-chemokines. Beta-chemokines also caused strong inhibition of viral uncoating and a considerable decrease in CCR5 expression during uncoating.
Conclusions: CCR5 receptors appear to be internalized and recycled to the cell surfaces during HIV entry. The down-regulation of CCR5 expression by beta-chemokines during virus uncoating probably accounts for the reduction in virus uncoating (entry) and hence in virus replication.