Possibility for Future AIDS Vaccine

HIV is a virus that attacks the immune system and weakens your ability to fight incoming infections and diseases. The Human Immunodeficiency Virus currently has no cure but there are currently treatments which are able to help people with the virus to live a prolonged, healthy life. Since there is no cure for HIV, the best way to approach preventing the spread of the virus is by vaccination; enabling the body to fight off the virus before it attacks the immune system. 

Researchers in the USA have been working on developing a vaccine capable of inducing "broadly neutralizing" antibodies that can prevent HIV infections. This new vaccine technique aims to immunize people with a series of different engineered HIV proteins as immunogens to "teach" the immune system to produce broadly neutralizing antibodies against HIV. This in turn, will prepare the immune system to fight off an incoming virus which carries similar proteins to the HIV proteins.

The group of researchers have found that the right precursor ("germline") cells for one kind of HIV broadly neutralizing antibody which is  present in most people, and have described the design of an HIV vaccine germline-targeting immunogen capable of binding those B cells. 

"We found that almost everybody has these broadly neutralizing antibody precursors, and that a precisely engineered protein can bind to these cells that have potential to develop into HIV broadly neutralizing antibody-producing cells, even in the presence of competition from other immune cells," said the study's lead author, William Schief, TSRI professor and director, Vaccine Design of the IAVI Neutralizing Antibody Center at TSRI, in whose lab the engineered HIV vaccine protein was developed.

The human immune system  consists of a large variety of variating precursor B cells so that it is able to respond to a large variety of pathogens (viruses and bacteria). However, this also means that the precursor B cells able to recognize a specific feature on a virus surface are exceedingly rare within the total pool of B cells.  

Our immune system is able to track and hunt down pathogens which carry markers (the proteins on the surface of the virus) for the HIV virus. This advance in research has lead to a phase 1 trial being initiated to clinical trial to test a nanoparticle version of the engineered HIV vaccine protein, the "eOD-GT8 60mer."

"The goal of the clinical study will be to test the safety and the ability of this engineered protein to elicit the desired immune response in humans that would look like the start of broadly neutralizing antibody development," Schief said. "Data from this new study was also important for designing the clinical trial, including the size and the methods of analysis."

In June 2015, researchers from TSRI, IAVI and The Rockefeller University reported that the eOD-GT8 60mer produced antibody responses in mice that showed some of the traits necessary to recognize and inhibit HIV. If the eOD-GT8 60mer performs similarly in humans, additional boost immunogens are thought to be needed to ultimately induce broadly neutralizing antibodies that can block HIV.

This new research has provided a new technique for researchers to determine if other new vaccine proteins can bind their intended precursor B cells. This technique is essential in manufacturing targeted and effective vaccines against HIV and AIDs. 

This research was published in the March 25, 2016 issue of Science, published by AAAS. The paper, by J.G. Jardine at Scripps Research Institute in La Jolla, CA, and colleagues was titled, "HIV-1 broadly neutralizing antibody precursor B cells revealed by germline-targeting immunogen."

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References:

The Scripps Research Institute. "New findings in humans provide encouraging foundation for upcoming AIDS vaccine clinical trial." ScienceDaily. ScienceDaily, 24 March 2016. 

https://www.sciencedaily.com/releases/2016/03/160324150047.htm