# Phospho-Chitooligosaccharides below 1 kDa Inhibit HIV-1 Entry In Vitro

## TL;DR

Phosphorylated chitosan oligosaccharides may prevent HIV-1 infection by blocking virus entry into cells.

## Contribution

This study demonstrates that phosphorylated chitosan oligosaccharides inhibit HIV-1 entry in vitro.

## Key findings

- PCOSs protected cells from HIV-1-induced lytic effects and reduced p24 protein production.
- PCOSs disrupted the binding of HIV-1 gp120 to CD4 receptors on T cells.
- The protective effect of PCOSs was lost when administered after infection.

## Abstract

Despite present antiviral agents that can effectively work against HIV-1 replication, side effects and drug resistance have pushed researchers toward novel approaches. In this context, there is a continued focus on discovering new and more effective antiviral compounds, particularly those that have a natural origin. Polysaccharides are known for their numerous bioactivities, including inhibiting HIV-1 infection and replication. In the present study, phosphorylated chitosan oligosaccharides (PCOSs) were evaluated for their anti-HIV-1 potential in vitro. Treatment with PCOSs effectively protected cells from HIV-1-induced lytic effects and suppressed the production of HIV-1 p24 protein. In addition, results show that PCOSs lost their protective effect upon post-infection treatment. According to the results of ELISA, PCOSs notably disrupted the binding of HIV-1 gp120 protein to T cell surface receptor CD4, which is required for HIV-1 entry. Overall, the results point out that PCOSs might prevent HIV-1 infection at the entry stage, possibly via blocking the viral entry through disruption of virus–cell fusion. Nevertheless, the current results only present the potential of PCOSs, and further studies to elucidate its action mechanism in detail are needed to employ phosphorylation of COSs as a method to develop novel antiviral agents.