At the end of 2013, there were 35 million people around the world living with the human immunodeficiency virus (HIV), many of them struggling with acquired immunodeficiency syndrome (AIDS) and the devastating effects of that illness. The World Health Organization reports that 1.5 million people died from AIDS during 2013 and that a total of 78 million people have been infected with HIV since the start of the epidemic decades ago. Rates of HIV/AIDS infection are still highest in sub-Saharan Africa, which home to about 71 percent of all adult cases of HIV/AIDS, but the disease has proliferated to points across the globe.
All of this means that whenever a step forward in the fight against AIDS occurs, it’s big news all over the world. That’s a big reason why medical and health news outlets have been buzzing about the recent successful clinical trial of VRC01, a monoclonal antibody demonstrated as having effectiveness in attacking HIV and slowing down the progression of related illnesses. According to news reports, VRC01 was able to attack and destroy HIV in an early Phase 1 clinical trial conducted at the Medical University of South Carolina and involving 23 HIV-infected individuals taking medication over the course of three weeks.
There are limits to the findings of this recent clinical trial. Patients who were already on antiretroviral therapy (ART) did not see much effect from the administration of VRC01, although many of those patients had their condition under control because of ART. However, in the case of six patients who were untreated, VRC01 was found to noticeably lower levels of HIV in an infected person’s blood by itself. Medical experts are hopeful that the successful development of VRC01 and similar antibodies would enable extensive use of cell-mediated immune defense techniques such as antibody-dependent cell-mediated cytotoxicity (ADCC), which involves binding antibodies to antigens found on the surface of infected cells in a way that encourages immune system cells to destroy the infection.
Proteins like VRC01 are referred to as broadly neutralizing antibodies (bNAbs), a type of broad spectrum antibody which is effective in treating against infections of viruses with high mutation rates, such as HIV as well as influenza. It’s thought that VRC01 and other bNAbs useful in treating HIV-infected patients is capable of identifying the envelope spike of a single HIV viral agent to inhibit or neutralize its effects. Research published in September from scientists working at the California Institute of Technology reported that a different bNAb known as 8ANC195 was capable of targeting an epitope, or position on an antigen to which an antibody can bind itself, which no other bNAb was capable of targeting.
In recent months, there has been a great deal of scientific research which has focused on the use of bNAbs to treat HIV, typically as part of a combination therapy which supply a variety of antibody compounds to an infected patient to attack the virus at multiple points. Often, bNAbs are derived from patients who have been infected with HIV but possess immune systems which have shown some ability to fight back against the virus. There are many strains of HIV, but part of what makes bNAbs such an effective treatment is their effectiveness against a wide range of viral strains; for instance, 3BNC117, another bNAb, recently demonstrated the ability to neutralize 195 HIV strains of a total of 237 total strains. In other research, VRC01 has shown effectiveness in combating 182 different strains of HIV.
The medical world has been able to create a number of retroviral medications and combination therapies which have made HIV/AIDS a much more manageable condition for infected patients. However, the fight against AIDS has run up against a behavioral issue: HIV is still regularly transmitted through unprotected sexual intercourse, and it’s difficult to get people to stop doing that, especially if they don’t know or believe that they are infected. An article on the top medical discoveries of 2015, published by The New Yorker, discussed a clinical trial pursued at a Parisian hospital where individuals took an antiviral medication before and after engaging in unprotected sex. Rates of HIV transmission were noticeably lower in the group receiving the antiviral medication versus those who had received a placebo.
Some scientists have also investigated the use of immunotherapy, typically used for the treatment of cancer patients, as a potential treatment for those suffering from HIV/AIDS. Cancer and HIV are somewhat similar in how they replicate as well as their ability to persist in patients despite therapy. Adoptive T cell therapies, in which treated T cells are administered to an infected patient to promote immune system functioning, has been looked at as a potential measure for treating HIV in patients. In 2016, a study will be conducted at the University of North Carolina to explore the effects in HIV patients of adoptive T cell therapy used in conjunction with Vorinostat, a cancer drug designed to provoke the accumulation of antigen proteins for easier targeting.
Gene editing tools may also be part of the solution that rids HIV/AIDS from the human race for good. The discovery of clustered regularly-interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (Cas) has given scientists hope that they’ll be able to efficiently edit genomes with a high degree of precision and flexibility. CRISPR sequences are expressed in bacteria and match viral DNA in a way that defends against those viruses. Cas is a related immune defense mechanism that works with CRISPR to slice through a virus’s DNA and eliminate it. Medical researchers working at the University of Massachusetts Medical School are applying CRISPR/Cas gene editing techniques to cut HIV DNA out of infected cells. Scientists are hoping to make the Cas genome cutting tool more precise so as to target HIV and avoid the negative effects of snipping non-diseased portions of DNA; challenges remain in identifying latent HIV residing in infected cells which may later become active.
There are other behavioral issues which have caused problems in the fight to eliminate HIV/AIDS, including getting infected patients to engage in safer behaviors or even undergo a course of treatment. About two-thirds of the estimated 1.2 million Americans living with HIV/AIDS are not in treatment for their disease and a disproportionate amount of this population is made up of African-American and Latino men. According to a recent report issued by the Centers for Disease Control and Prevention, Baton Rouge, Miami and New Orleans rank highest among American metropolitan areas in terms of new diagnoses of HIV/AIDS, but numbers were increasing for every city reporting statistics. Even when insurance is able to cover costs for low-income or impoverished patients, there are still many HIV-infected patients who fall out of their treatment plan.