Siglec-1 RNAi interference and competitive inhibition by a GM3 glycan mimetic inhibits HIV-1 VLP internalization by MDMs.

(A) MDMs were transfected with 60 nM control or Siglec-1 siRNA on day 8 after plating. Cell lysates were harvested and analyzed by Western blotting for Siglec-1 and actin expression. (B) MDMs were transfected with either control or Siglec-1 siRNA and 5 days later incubated with 400 ng of HIV-1 Gag-EGFP VLPs for 2 hr. Cells were washed and cell lysate p24 concentration determined by ELISA. (C) MDMs were pre-treated at RT with lactose or 3’-sialyllactose for 1 hour. Subsequently, MDMs were incubated with 400 ng of HIV-1 Gag-EGFP VLPs in the presence of compound for an additional hour. MDMs were then washed, cell lysates harvested and cell-associated p24 measured by ELISA. Error bars represent standard deviation; asterisks depict significant differences as measured by unpaired t-test.