Effects of pre-incubation of virus preparations or target cells with PS extracts or reference compounds on inhibition of HIV-1 infection.

Inhibition of HIV-1 infection by PS extract was enhanced by pre-incubation of virus preparations with PS extract, compared to inhibition of infection without virus pre-incubation. HIV-1 target cells pre-incubated with PS extract prior to infection did not retain HIV-1 inhibitory activity. Virus pre-incubation (green curves): Inhibitory activity of PS extract was assayed with HIV-1_LAI virus preparations pre-incubated with different concentrations of PS extract for 4 hours before adding to LC5-RIC cells. Target cell pre-incubation (black curves): LC5-RIC cells were incubated with different concentrations of inhibitors and subsequently exposed to HIV-1_LAI in fresh medium in the absence of inhibitors. No pre-incubation (blue curves): Virus and inhibitors were added simultaneously to LC5-RIC cells. The entry inhibitors Griffithsin, AMD3100 and T20 and the reverse transcriptase inhibitor Efavirenz were analyzed as reference compounds. Mean values of triplicate wells and standard deviation of the mean are indicated for each extract concentration.