Tag Archives: HIV

How To Stop Influenza Virus

The critical, structural changes that enveloped viruses, such as HIV, Ebola and influenza, undergo before invading host cells have been revealed by scientists using nano-infrared spectroscopic imaging, according to a study led by Georgia State University and the University of Georgia. The researchers found that an antiviral compound was effective in stopping the influenza virus from entering host cells during lower pH exposure, the optimal condition for the virus to cause infection.

Enveloped viruses are among the most deadly known viruses. These viruses have an outer membrane covering their genetic material, and to invade host cells enveloped viruses must first attach to a cell and then open their membrane to release genetic material. Originally, scientists believed this mechanism was controlled by the host cell. In this study, which focused on influenza virus, the researchers examined the structural changes that occur for the virus to open and release its genetic material. They conducted the experiment in the absence of cells and instead simulated the cell environment. When influenza virus infects a person’s body, it goes from a neutral environment outside the cell to a more acidic environment (a lower pH) inside the cell. To simulate the cell environment for this study, the researchers made the environment more acidic. The researchers exposed influenza virus particles to the lower pH and monitored structural changes in the virus.

What we saw is that even without the cell, if we change the environment, the virus particle will break and release the genetic material,” said Dr. Ming Luo, a senior author of the study and professor in the Department of Chemistry at Georgia State. “So it has a proactive mechanism built into the virus particle. Once the virus particle finds that the environment has changed, it will itself release the material. It doesn’t need the help of the cell membrane. It has to find a sweet spot to release the genetic material, and that sweet spot happens to have a low pH.”

The researchers used nano-infrared spectroscopy, a microscopic imaging system, to observe how influenza virus particles change when their environment changes. During his work at Georgia State, Dr. Yohannes Abate, now at the University of Georgia, adapted the imaging technology to have a new, unique function that allowed them to study virus particles in more detail.

The findings are published in the journal PLoS One.

Source: https://news.gsu.edu/

Universal Antibody Drug for HIV

A research team led by scientists at AIDS Institute and Department of Microbiology, Li Ka Shing Faculty of Medicine of The University of Hong Kong (HKU) invents a universal antibody drug against HIV/AIDS. By engineering a tandem bi-specific broadly neutralizing antibody, the team found that this novel antibody drug is universally effective not only against all genetically divergent global HIV-1 strains tested but also promoting the elimination of latently infected cells in a humanized mouse model. The new findings are now published in the Journal of Clinical Investigation, one of the world’s leading biomedical journals.

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AIDS remains an incurable disease. In the world, HIV/AIDS has resulted in estimated 40 million deaths while 36.9 million people are still living with the virus.  To end the HIV/AIDS pandemic, it is important to discover either an effective vaccine or a therapeutic cure. There are, however, two major scientific challenges: the tremendous HIV-1 diversity and the antiviral drug-unreachable latency. Since it is extremely difficult to develop an appropriate immunogen to elicit broadly neutralizing antibodies (bnAbs) against genetically divergent HIV-1 subtypes, developing existing bnAbs as passive immunization becomes a useful approach for HIV-1 prophylaxis and immunotherapy.

Previous studies have investigated the potency, breadth and crystal structure of many bnAbs including their combination both in vitro and in vivo. Naturally occurring HIV-1 resistant strains, however, are readily found against these so-called bnAbs and result in the failure of durable viral suppression in bnAb-based monotherapy. To improve HIV-1 neutralization breadth and potency, bispecific bnAb, which blocks two essential steps of HIV-1 entry into target cells, have been engineered and show promising efficacy in animal models. Before the publication, tandem bi-specific bnAb has not been previously investigated in vivo against HIV-1 infection.

Source: https://www.med.hku.hk/