Direct visualization of HIV-enhancing endogenous amyloid fibrils in human semen

Area of Science:

• * Virology and Biochemistry
• * Human Reproductive Health

Background:

• * Naturally occurring semen proteins, prostatic acid phosphatase (PAP) and semenogelins, can form amyloid fibrils in vitro.
• * These amyloid fibrils are known to enhance HIV infection.
• * The in vivo presence and role of amyloid fibrils in human semen were previously unconfirmed.

Purpose of the Study:

• * To directly visualize and characterize amyloid fibrils in human ejaculates.
• * To determine if naturally occurring amyloid fibrils in semen interact with HIV.
• * To assess the impact of these fibrils on HIV infectivity.

Main Methods:

• * Advanced confocal and electron microscopy techniques were employed for direct imaging.
• * Human semen samples were analyzed for the presence of amyloid aggregates.
• * Interactions between detected fibrils and HIV particles were investigated.

Main Results:

• * Amyloid aggregates were detected in all analyzed human semen samples.
• * These aggregates were found to partially comprise prostatic acid phosphatase (PAP) fragments.
• * The identified amyloid fibrils interact with HIV particles and significantly increase viral infectivity.

Conclusions:

• * Human semen naturally contains amyloid fibrils.
• * These naturally occurring amyloid fibrils, including PAP fragments, play a role in promoting HIV sexual transmission.
• * The findings highlight a novel mechanism exploited by HIV for propagation.