Out of four to six patients tested for each compartment, approximately one-third typically responded to Poly(I:C) by up-regulating Trappin-2/Elafin. Trappin-2/Elafin is a known antibacterial

molecule that has been shown to be effective against both Gram-positive and Gram-negative bacteria.39 R428 As we demonstrated that a synthetic dsRNA analog Poly(I:C) enhances Trappin-2/Elafin production/secretion from FRT epithelial cells, we investigated whether Trappin-2/Elafin could have direct antiviral activity. Because HIV-1 is an important sexually transmitted pathogen, we tested the activity of rTrappin-2/Elafin against HIV-1 X4/T-tropic IIIB and R5/M-tropic BaL. HIV-1 IIIB and BaL were incubated with rTrappin-2/Elafin at 0·01, 0·1, 1 or 10 ng/ml for 1 hr at 37°. TZM-bl indicator cells were plated the previous day at 25 000 cells per well and grown to 70–80% confluence. The virus–Trappin-2/Elafin mixture was added to the TZM cells and incubated for 48 hr at 37°. At the end of the incubation period, Beta-Glo substrate was added to the cells and viral infection was quantified in relative light units using a luminometer. The data were expressed as per cent of control with the virus-only control set at 100%. As shown in Fig. 3, rTrappin-2/Elafin

significantly inhibited both IIIB and BaL at all the concentrations Selumetinib tested, achieving up to 80% inhibition of IIIB and up to 60% inhibition of BaL. We demonstrated, by ELISA, that the biological concentrations of Trappin-2/Elafin secreted by epithelial P-type ATPase cells, both constitutively and upon Poly(I:C) stimulation, ranged between 0·25 and 9 ng/ml. Therefore, the concentrations of Trappin-2/Elafin showing anti-HIV-1 activity were in the range of physiological levels of this molecule that are secreted by the FRT epithelial cells. Because the inhibitory activity was observed as a result of pre-incubation of HIV-1 with rTrappin-2/Elafin, we believe that the effect of Trappin-2/Elafin on viral infection was direct. Viability studies were conducted in parallel to demonstrate that the inhibitory activity observed

was not caused by the toxic effect of rTrappin-2/Elafin on the TZM cells (data not shown). Anti-HIV factors have been shown to inhibit HIV by multiple mechanisms, including through direct interaction with HIV, by blocking cell-surface receptors (CXCR4, CCR5) and by affecting postinfection steps.40,52,53 To demonstrate whether rTrappin-2/Elafin might also have indirect effects on HIV-1 infection by blocking any cell-surface receptors or molecules, we pre-incubated the TZM cells with 0·1 and 1 ng/ml of rTrappin-2/Elafin for 1 hr at 37°. Following incubation, cells were washed repeatedly with 1 × PBS before the addition of HIV-1 IIIB and BaL after which the cells were incubated for 48 hr and infectivity assessed.