A series of [Leu5]enkephalin-relatedglycoconjugates with an ester-, ether-, or amide-type linkage were synthesized and evaluated for antiviral activity againstHIV-1 in a cell-culture system using peripheral blood lymphocytes. All tested glycoconjugates exhibited a certain antiviral activity which was significantly higher than the activity of the parent peptide compound itself. These results indicate