Problem: Semen is the primary medium for sexual transmission of HIV-1 and contains high concentrations of TGF-β1, but its role in regulating HIV-mediated immune activation is unclear.
Method of study: TGF-β1 and sCD14 were compared in blood plasma (BP) and seminal plasma (SP) from HIV-uninfected and infected, antiretroviral therapy (ART)-naive and ART-treated men and in THP-1 cells following exposure to HIV-1. The relationship between TGF-β1 and sCD14 was determined by Spearman correlation.
Results: Active and latent forms of TGF-β1 were compartmentalized between BP and SP. Highest active TGF-β1 levels were present in SP of ART-naïve chronic-infected men and decreased following ART treatment. Latent TGF-β1 was upregulated in BP following HIV infection, and highest levels were observed in BP of acute-infected men. Similar expression trends were observed between latent TGF-β1 and sCD14 in BP. A significant negative correlation was observed between active TGF-β1, sCD14, and semen viral load in ART-naive men.
Conclusion: TGF-β1 is compartmentalized between blood and semen, possibly co-expressed with sCD14 by activated monocytes/macrophages in BP as a result of HIV infection. Conversion of latent TGF-β1 into its active form could contribute to regulation of viral load and immune activation in the male genital tract, but depends on the stage of infection.
Keywords: Blood plasma; HIV-1; TGF-β1; immune activation; sCD14; seminal plasma.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.