The mention of HIV usually evokes a sense of dread in people as the condition is perceived as that deadly disease that has no cure. What if an HIV vaccine that could potentially kill the virus is being developed?
Following the emergence of HIV in 1984, scientists have worked tirelessly to find a cure. In fact, the US department of health and human services was positive about finding a cure within two years, but all efforts to completely overcome the tricky virus have proved abortive.
The only headway made was the production of Anti-Retro-viral drugs to counter the effects of the virus. But the drugs only help to lessen the viral load in individuals such that it is almost untraceable in the blood. Anti-retro-viral drugs must be taken daily at specific times to prevent the virus from replicating in the body. Once a dosage is skipped, the virus might become resistant to the drugs and all previous efforts will be defeated.
Taking frequent medication can be quite burdensome. Aside from having a strict adherence policy, it also has side effects such as cardiovascular diseases, bleeding problems, loss of bone mass, diarrhea, nausea, mood swings, and diabetes. In the bid to find a lasting cure, scientists have intensified their efforts towards making the ultimate “HIV breakthrough”. One of such cases is the Scripps Experimental HIV vaccine.
What makes HIV very difficult to kill is the rate at which it mutates. The virus can change its form to avoid being targeted by antibodies. It further embeds itself within the DNA of T helper cells and becomes latent while a person is taking ART.
Once the medication is stopped, the virus can become active and lead to AIDS. The Scripps research published in the immunity journal is built around broadly neutralizing antibodies (bnAbs), these antibodies are produced by the B cells.
They can bind to the virus and subsequently render it obsolete. bnAbs is a rarity in the blood. Some few infected people produce these antibodies but in very few amounts and usually at a later stage of infection, when it is too late.
Research On HIV Vaccine
The research team developed a vaccine based on HIV protein. The viral protein binds to immune cells through the CD4 receptors and breaks into host cells. They engineered virus mimicking proteins that bore a resemblance to the actual HIV protein. These proteins can stimulate numerous B cells to produce antibodies that can attack the virus when vaccination occurs.
Immunology tests were then carried out to test if the curated proteins can bind to the normal circulating B cells. They tested blood samples from HIV infected people and discovered that the immunogens bind perfectly to the targeted antibodies.
The team then infused the immunogens with glycan which shields the CD4 receptors from antibody attack. This was necessary to detect antibodies that can attack the binding site and get through its shield as well. To obtain a diverse result, they used proteins with different HIV strains.
To check if the proteins can stimulate B cells into producing the rare and special antibodies that can attack and penetrate the virus, the team inoculated 12 rabbits with the designated immunogens carrying glycan shields.
Five of the rabbits produced antibodies that can attack and penetrate different strains of HIV. They also identified two special bnAbs, E70 and IC2, produced by the rabbits. While E70 grabs one of the glycan shields and blocks the CD4 receptor, IC2, on the other hand, hits the interface of the protein which is vulnerable.
The binding of the IC2 renders the virus obsolete. It also neutralized 87% of 208 HIV isolates.
This research goes a long way in suggesting that a potential cure for HIV is well on the way. The researchers are still testing the vaccine in animal models and will eventually begin to test the potency of the vaccine in humans.
Another similar research carried out by scientists at Fred Hutchinson Cancer research center, Seattle, made use of Anti-idiotypic antibodies, which are proteins that can attach to other antibodies. These proteins were first discovered in 1960.
The scientists engineered anti – ids that can attach to special bnAbs that counter HIV protein. The purpose behind their research is to use the protein as a bait to induce B cells into making the rare bnAbs that can fight HIV.
They believe that when this piece of protein is injected into the body it can lure out bnAbs such as VRCO1 that can wad off the virus. The researchers have already created a series of proteins and are currently testing them in mice.
In both types of research, we find that one key medium to producing a successful HIV vaccine is to stimulate the body to produce HIV fighting antibodies which are very rare. The immunogens are antibody specific and will mostly latch onto these special breeds of antibodies that can prevent the viral protein from initiating entry into the host cells by blocking the binding site.