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. Author manuscript; available in PMC: 2015 Jun 1.

Published in final edited form as: Int J Biochem Cell Biol. 2014 Mar 22;51:10–18. doi: 10.1016/j.biocel.2014.03.008

Fig. 6 — (A) The viral gp120 binding to the CD4 receptor on the host T cells, initiates a cascade of events including Conformational change, recruitment of CCR5 and/or CXCR4 co-receptor that results in the fusion of HIV-1 host cell membrane and subsequent entry of HIV-1 RNA genome into host cells. Blockage of the gp120-CD4 interaction by CD4 aptamer may inhibit HIV infection. (B) Karpas 299 cells were pre-incubated with aptamers at a concentration of 10 μM for 30 min. Cells were washed and subsequently incubated with FITC-labeled gp120 for 30 mins, and bound gp120 was detected by flow cytometry. All four CD4-binding DNA aptamers reduced gp120 binding to CD4-positive cells. The DNA library was included as a negative control. (C) Karpas 299 cells were incubated with 10 μM streptavidin-conjugated aptamer #1-62 polymers or 10 μM monomeric aptamer #1-62 and tested in our gp120 binding assay. Whereas monomeric aptamer #1-62 reduced gp120 to 47.4% of control levels, gp120 binding was reduced to 31.1% in the presence of tetrameric aptamer #1-62. (D) Karpas 299 cells were incubated with increasing concentrations (1 to 20 μM) of tetrameric aptamer #1-62 and FITC-labeled gp120 was added at 30 min post. At 10 μM, only 30% of cells bound gp120. (E) Karpas 299 cells were incubated first with gp120-FITC for 30 minutes and then the indicated concentrations of tetrameric aptamer #1-62 were added. Gp120 binding was disrupted in a dose-dependent manner.

Fig. 6 — (A) The viral gp120 binding to the CD4 receptor on the host T cells, initiates a cascade of events including Conformational change, recruitment of CCR5 and/or CXCR4 co-receptor that results in the fusion of HIV-1 host cell membrane and subsequent entry of HIV-1 RNA genome into host cells. Blockage of the gp120-CD4 interaction by CD4 aptamer may inhibit HIV infection. (B) Karpas 299 cells were pre-incubated with aptamers at a concentration of 10 μM for 30 min. Cells were washed and subsequently incubated with FITC-labeled gp120 for 30 mins, and bound gp120 was detected by flow cytometry. All four CD4-binding DNA aptamers reduced gp120 binding to CD4-positive cells. The DNA library was included as a negative control. (C) Karpas 299 cells were incubated with 10 μM streptavidin-conjugated aptamer #1-62 polymers or 10 μM monomeric aptamer #1-62 and tested in our gp120 binding assay. Whereas monomeric aptamer #1-62 reduced gp120 to 47.4% of control levels, gp120 binding was reduced to 31.1% in the presence of tetrameric aptamer #1-62. (D) Karpas 299 cells were incubated with increasing concentrations (1 to 20 μM) of tetrameric aptamer #1-62 and FITC-labeled gp120 was added at 30 min post. At 10 μM, only 30% of cells bound gp120. (E) Karpas 299 cells were incubated first with gp120-FITC for 30 minutes and then the indicated concentrations of tetrameric aptamer #1-62 were added. Gp120 binding was disrupted in a dose-dependent manner.