The Role of a Sugar Molecule on HIV-infected Cells in Evading the Immune System

Approximately 38 million people are living with HIV, and many people living with HIV do not have adequate access to treatment, care, and there is no cure yet as well. A new study by researchers at the Wistar Institute showed how key features on the surface of HIV-infected cells allow the disease to evade detection from our immune systems. More promisingly they showed how these features can be disabled as well. In this new study, researchers looked at a type of sugar molecule called celiac acid on the surface of HIV-infected cells.  

Sialic acid sugars bind with receptors called siglecs on the surface of disease-fighting immune cells and act as inhibitors to the cell signaling immune response. The researchers hypothesized that the HIV-infected cells were covering themselves with these sugars to use this interaction to their advantage and remain undetected to the body's immune surveillance. After finding out that this was the case they investigated whether they could “manipulate this connection” to make the immune cells more effective at killing HIV-infected cells. They first used an enzyme called sialidase to remove sialic acid that was causing the immune inhibition. However, this caused the immune cells to indiscriminately attack cells. Then they developed a sialidase conjugate linked to HIV antibodies that only targeted sialic acid on HIV cells.  Consequently the HIV-infected cells had the sialic acid removed and were attacked by immune cells while the healthy cells were not.

 

The selective manner of this process allowed the immune cells to become “super killers” for HIV-infected cells. By removing sialic acid from the surfaces of HIV-infected cells, the cells actually become more susceptible to being attacked which has been a crucial research need in the HIV field. It was noted that this approach could be tested in combination with broadly neutralizing antibody therapies currently being studied in clinical trials. Even more promising the researchers noted that the approach may have clinical application in treating other infectious diseases that evade the immune system like hepatitis and COVID. The researchers are now investigating other sugars molecules on HIV cells that may play a similar role to sialic acid.

 

https://www.sciencedaily.com/releases/2021/11/211111154224.htm

Declan Downing (7)