A ‘Super’ Receptor That Helps Kill HIV Infected Cells


Source: Monash University

Summary: Researchers have discovered a unique set of “super” receptors on immune cells capable of killing HIV across genetically diverse populations, making them a potential candidate for immunotherapy treatments.


While treatments for HIV mean that the disease is no longer largely fatal, the world still lacks a true therapy that can eradicate the virus across a globally and genetically different population. Upon HIV infection, CD4 T cells, which are an important part of our protective immune system, can be depleted and drop dramatically in numbers, leading to a weak immune system with the progression of the disease to AIDS. These CD4 T cells can remain low even when the disease is kept in check with antiretroviral therapy (ART), which is currently provided to more than half of people living with HIV globally. ART lowers the risk of mortality but does not eradicate the virus. Researchers from the Monash University have discovered a unique set of “super” receptors on immune cells capable of killing HIV across genetically diverse populations, making them a potential candidate for immunotherapy treatments. The study findings were published in the journal Science Immunology.

CD4+ T cells

CD4+ T cells, or helper T cells, in HIV controllers, can interact with various HLA class II molecules presenting the same “piece” of HIV. These CD4+ T cells display cell-killing activity to suppress HIV. Credit: Vanette Tran

The team found that HIV controllers are able to retain CD4 T cells of a higher quality, and are able to detect and react to minute amounts of virus, therefore representing a great opportunity to study their potential role in HIV infection. Tcell receptors recognize virus or bacteria fragments bound to a specialized molecule called Human Leukocyte Antigen (HLA). HLA molecules are like fingerprints: every person has a specific combination of HLA molecules, which help the immune system recognize foreign invaders like bacteria or viruses. Australian Synchrotron, effectively a giant microscope is used to study the binding of this super T-cell receptor in complex with the HIV antigen. This revealed another remarkable feature of those killer CD4 T cells: their ability to recognize HIV fragment in genetically diverse individuals.

A co-lead author of the study, Dr. Carine Farenc said, “The likelihood of finding the exact same T cell receptor in different individuals is extremely low, like winning the lottery, and is likely playing a role in the control of HIV.”


More Information: M. Galperin et al, “CD4+ T cell-mediated HLA class II cross-restriction in HIV controllers,” Science Immunology (2018). immunology.sciencemag.org/look … 6/sciimmunol.aat0687 


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