Sensitivity of pseudotypes to the entry inhibitor HNG-105. Pseudotypes were incubated for 1 h. at 37°C with the gp120-targeted short peptide HNG-105 and then the mixture was added to HOS-CD4-CCR5 cells. Pseudotypes containing BR, BR(N283T) and BS Env were significantly more sensitive than those with SPL, SB, Bv1v3 or Bv1v2. DS17 and DS17(N283T) did not differ between them and showed similar sensitivity to HNG-105 than BR, BR(N283T) and BS. Data from a representative experiment repeated at least 3 times with similar results are shown.