Recently, it has been shown that human ejaculate enhances human immunodeficiency virus 1 (HIV-1) infectivity.\r\nEnhancement of infectivity is conceived to be mediated by amyloid filaments from peptides that are proteolytically\r\nreleased from prostatic acid phosphatase (PAP), termed Semen-derived Enhancer of Virus Infection (SEVI). The aim\r\nof this study was to test the range of HIV-1 infectivity enhancing properties of a large number of individual semen\r\nsamples (n = 47) in a TZM-bl reporter cell HIV infection system. We find that semen overall increased infectivity to\r\n156% of the control experiment without semen, albeit with great inter- and intraindividual variability (range -53%-\r\n363%). Using transmission electron microscopy, we provide evidence for SEVI fibrils in fresh human semen for the\r\nfirst time. Moreover, we confirm that the infectivity enhancing property can be inhibited by the major green tea\r\ningredient epigallocatechin-3-gallate (EGCG) at non-toxic concentrations. The median inhibition of infection by\r\ntreatment with 0.4 mM EGCG was 70.6% (p < 0.0001) in our cohort. Yet, there were substantial variations of\r\ninhibition and in a minority of samples, infectivity enhancement was not inhibited by EGCG treatment at all. Thus,\r\ntopical application of EGCG may be a feasible additional measure to prevent the sexual transmission of HIV.\r\nHowever, the reasons for the variability in the efficacy of the abrogation of semen-mediated enhancement of HIV-1\r\ninfectivity and EGCG efficacy have to be elucidated before therapeutic trials can be conducted.
Loading....