HIV vaccine design has made breakthrough progress
A team of researchers from The Scripps Research Institute (TSRI) has designed a new immunogen based on the structures of the envelope glycoprotein from a common HIV subtype, HIV-C. This immunogen may aid in developing a vaccine that fights against multiple strains of HIV.
The human immunodeficiency virus (HIV) is the cause of acquired immunodeficiency syndrome (AIDS), a condition in which a compromised immune system allows life-threatening opportunistic infections and cancers to thrive. According to estimates, HIV affected about 36.7 million people around the world in 2015, killing more than 1 million people in the same year.
The treatment of HIV has improved greatly due to the use of antiretroviral (ARV) drugs. However, these drugs do not cure people of HIV or AIDS and people have to take them for a lifetime. Once a person with HIV stops taking the drugs, the virus can become active again. Additionally, long-term use of ARVs has side effects, such as diarrhea, fatigue, skin rashes, and trouble sleeping.
Despite advances in our understanding of HIV infection, it is still difficult to find a powerful drug or vaccine for HIV. Firstly, HIV is severely species restricted: only humans and chimpanzees have shown to be susceptible to infection. This limits the use of animal models in HIV research. Secondly, HIV mutates too rapidly for the immune system to combat, because its genetic material is RNA rather than DNA. Currently, there are many different strains of HIV circulating around the world. HIV clade A (HIV-A), HIV clade B (HIV-B), and HIV clade C (HIV-C) are among the most prevalent threats.
A successful vaccine needs to protect against multiple strains. Therefore, it is important to identify a set of immunogens that could elicit immune responses against various HIV strains. TSRI researchers focused on HIV envelope glycoprotein (Env), because this viral protein plays a vital role in the ability of HIV to enter host cells and is the sole antibody target on the surface of HIV.
Env structures of HIV-A, B, and G have been solved, and scientists have generated mimics of these Env structures, which elicit neutralizing antibodies. However, Env structure of HIV-C has not yet been obtained. In this study, TSRI researchers generated a stabilized, soluble HIV-C Env (16055 NFL) and determined its crystal structure.
The study is published 16 May 2017 in Immunity.