Understanding how the HIV virus evades immune surveillance

About 36 million people have died from AIDS-related illnesses and approximately 38 million people globally are living with HIV.

Dr. Jonathan Cook, a resident physician specializing in medical microbiology at the University of Toronto, is investigating key proteins on the HIV virus that are crucial to developing an effective vaccine.

“These proteins are so interesting because they are necessary for a virus to infect a human,” said Cook. “By blocking their function, we can avert the kinds of infections that you see routinely.”

He and Adree Khondker in the lab of Prof. Jeffrey E. Lee from the Temerty Faculty of Medicine published a paper in Communications Biology that reveals new information on how the HIV virus interacts with immune systems.

Using the CMFC beamline at the Canadian Light Source at the University of Saskatchewan, the research team analyzed the outer proteins on the HIV virus. They discovered that an area of one protein acts as a decoy — diverting the immune system’s response towards a false target.

This tactic allows the virus to successfully infect human cells and to cause disease.

“The immune system recognizes this sequence on the virus, which is usually a good thing. But, in this situation, the antibodies that the immune system makes don’t protect you from infection,” Cook said.

With the help of the CLS, the researchers confirmed that this decoy area on the HIV protein shapeshifts to entice an ineffective immune response.

Read more on the CLS website

Image: Micrographs of crystals from this project that were diffracted at CLS

Insights into coronavirus proteins using SAXS

A collaboration led by researchers from the European Molecular Biology Laboratory (EMBL) used small angle X-ray scattering (SAXS) at the European XFEL and obtained interesting data on samples containing coronavirus spike proteins including proteins of the isolated receptor biding domain. The results can, for example, help investigate how antibodies bind to the virus. This gives researchers a new tool that may improve understanding of our bodies’ immune response to coronavirus and help to develop medical strategies to overcome COVID-19

SAXS is a powerful technique as it allows researchers to gain insights into protein shape and function at the micro- and nanoscales. The technique has proven to be extremely useful in investigating macromolecular structures such as proteins, especially because it removes the need to crystallize these samples. This means researchers can study the sample in its native form under physiological conditions under which biological reactions occur.

Read more on the European XFEL website

Image: Seen here, the instrument SPB/SFX, where the SAXS experiment was carried out. Using this instrument researchers can study the three-dimensional structures of biological objects. Examples are biological molecules including crystals of macromolecules and macromolecular complexes as well as viruses, organelles, and cells.

Credit: European XFEL / Jan Hosan