Problem: CCL20/MIP3alpha is a chemokine for immature dendritic cells as well as an antibacterial against gram-positive and gram-negative bacteria. The role of CCL20/MIP3alpha as an antiviral is unknown. In this study, we have examined the production of CCL20/MIP3alpha by epithelial cells from the upper female reproductive tract as well as its activity as an antiviral molecule.
Method of study: Primary uterine and Fallopian tube epithelial cells were treated with Poly(I:C) and CCL20/MIP3alpha mRNA and protein was measured by Realtime RT-PCR and ELISA assays. Anti-HIV activity was determined using an indicator cell line TZM-bl and quantified by using a luminometer.
Results: Primary uterine and Fallopian tube epithelial cells produce CCL20/MIP3alpha constitutively and the production is enhanced following stimulation with viral double-stranded RNA mimic Poly(I:C). Recombinant CCL20/MIP3alpha was able to inhibit both T-cell-tropic X4/IIIB and macrophage-tropic R5/BaL HIV-1 when virus was directly incubated with CCL20/MIP3alpha but not when CCL20/MIP3alpha was added to cells either prior to infection or post-infection. This suggests that the mechanism of inhibition is likely to be a direct interaction between HIV-1 and CCL20/MIP3alpha.
Conclusion: This study demonstrates that CCL20/MIP3alpha is an important endogenous anti-HIV-1 microbicide of the female reproductive tract.