Read the following articles. Based on the lectures, write an essay explaining how HIV affects the immune system andevaluating the role of science in finding treatments for people with HIV/AIDS. Take into consideration social, economic and ethical aspects.
Essay: 300-400 words, with references, in computer (do not copy from internet).
Criteria Evaluated: Criterion A and Criterion B.
Understanding HIV infection: HIV? AIDS?
Adapted from: Terence Higgins Trust. 2007. HIV and AIDS: understanding HIV Infection. 5th edition. Available at http://www.tht.org.uk/informationresources/hivandaids/
What is HIV and AIDS?
HIV stands for Human Immunodeficiency Virus. It is a viral infection that attacks the human body’s immune system. Initially a person may show no symptoms of HIV infection as their immune system manages to control it. However, in most cases, the immune system will require help from anti-HIV drugs to keep the HIV infection under control. These drugs do not completely rid the body of HIV infection. AIDS (Acquired Immune Deficiency Syndrome) as a term is now very rarely used. It is more usual to talk of late-stage or advanced HIV infection. AIDS is not a single disease or condition, it is a term that is used to describe the point when a person’s immune system can no longer cope, because of damage caused by HIV and specific illnesses start to appear. People do not actually die from AIDS; they die from the cancers, pneumonia or other conditions that may take hold when their immune system has been weakened by HIV.
How does HIV affect the body?
After a while, HIV will begin to weaken the body’s immune system, which usually fights off any infections. HIV reproduces even in someone who may be feeling well. If their immune system is working well, the virus may only reproduce a little. But if their immune system is weakened through illness, the virus can reproduce itself much more easily. Research shows that people with higher levels of HIV in their bodies have a greater risk of becoming ill than people with less HIV in their bodies.
As the HIV reproduces itself, the person is more vulnerable to other infections. Normally many of these infections would be controlled by an effective immune system, but in someone with HIV and a weakened immune system they can become more serious and in some cases fatal. These illnesses are often called ‘opportunistic infections’.
Using anti-HIV treatments can slow this process down. They do not clear the body of HIV infection but do help control the amount of virus. If the HIV is controlled, the person’s immune system is better able to deal with any other infections.
How effective is anti-HIV treatment?
Taking a combination of anti-HIV drugs (combination therapy) can successfully reduce the level of HIV in the blood, and in many cases have a dramatic effect in improving the health and life expectancy of someone with HIV. However, the longer term effects of these treatments and for how long they remain effective is still unknown.
Is there now a cure for HIV?
At present there is no cure for HIV infection. Drug combinations do not completely eliminate HIV from the body; they at best control it. There is still no vaccine to prevent people becoming infected with HIV.
Taken from: http://www.dailyfinance.com/2010/07/08/scientists-discover-antibodies-that-could-help-create-aids-vacci/
AIDS AntibodiesU.S. government scientists have discovered two potent human antibodies that can stop more than 90% of known global HIV strains from infecting human cells, the National Institute of Health announced Thursday.
The scientists first discovered the two naturally occurring, powerful antibodies in the blood of an HIV-infected individual. Scientists found that the antibodies, called VRC01 and VRC02, not only neutralize more HIV strains, but they do so with greater strength than previously known antibodies.
So far, scientists have found the HIV virus extremely tricky to work with for the purpose of creating a vaccine. It has been difficult to find individual antibodies that can neutralize HIV strains anywhere in the world because the virus continuously changes to evade recognition by the immune system. Which also explains why so many HIV strains exist worldwide. Last year, the most promising vaccine trial to date managed to help only less than a third of the individuals.
Still, scientists were able to identify a few areas on HIV's surface that remain nearly constant across all variants. One such area is called the CD4 binding site. VRC01 and VRC02 block HIV infection by attaching to the CD4 binding site, preventing the virus from latching onto immune cells.
Still in the Lab
With this knowledge, researchers have begun the difficult work of designing a possible vaccine that could teach the human immune system to make its own antibodies similar to VRC01 that might prevent infection by the vast majority of HIV strains worldwide. So far, their work has been done only in cells in a laboratory.
"The discovery of these exceptionally broadly neutralizing antibodies to HIV and the structural analysis that explains how they work are exciting advances that will accelerate our efforts to find a preventive HIV vaccine for global use," Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health said in a statement.
"The discoveries we have made may overcome the limitations that have long stymied antibody-based HIV vaccine design," Dr. Peter D. Kwong, one of the NIAID scientists who led the research, added.
Not only that, the method used to find these antibodies could be applied to isolate therapeutic antibodies for other infectious diseases as well.
The U.S. HIV/AIDS epidemic began in 1981, according to the NIAID, and 566,000 people in the U.S. have died of AIDS since. At the end of 2006, an estimated 1.1 million people in the U.S. were living with diagnosed or undiagnosed HIV/AIDS, and over 56,000 new infections were recorded. Globally, 33 million people have lived with HIV/AIDS, and 2 million died of related illnesses in 2007. And since its discovery, 25 million people have died of AIDS worldwide. Although drugs can help control the disease, there's still no vaccine for it.
NIAID Describes Challenges, Prospects For An HIV Vaccine
Taken from: http://www.sciencedaily.com/releases/2008/08/080827195736.htm
ScienceDaily (Aug. 27, 2008) — Events of the past year in HIV vaccine research have led some to question whether an effective HIV vaccine will ever be developed. In the August 28 edition of the New England Journal of Medicine, officials from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, examine the extraordinarily challenging properties of the virus that have made a vaccine elusive and outline the scientific questions that, if answered, could lead to an effective HIV vaccine.
In recent years, the most extensively studied HIV vaccines have aimed to mobilize immune cells called T cells (or T-lymphocytes, a specific type of lymphocytes), write Anthony S. Fauci, M.D., NIAID director, and Margaret I. Johnston, Ph.D., director of the Vaccine Research Program in NIAID's Division of AIDS.
T-cell vaccines are not expected to prevent HIV infection. Rather, they could potentially reduce the level of virus (but not eliminate it) following infection, limit the number of immune cells that HIV destroys, and thus delay the progression to AIDS. There is no evidence yet that T-cell HIV vaccines work in humans, however.
If the vaccines ultimately do, their effectiveness may vary greatly depending on the genetic make-up of each individual, given that T-cell immunity is dependent on genetic factors. Furthermore, because the virus would persist in the blood of vaccinated individuals, T-cell vaccines would likely generate only transient "herd immunity"--that is, population-wide protection from disease conferred by vaccination of a percentage of the community.
In response to the failure last September of a T-cell vaccine for which many people had high hopes, the HIV vaccine field has undergone a self-reexamination and has determined that the balance between fundamental discovery research and product development should shift toward discovery. In particular, future research must intensify the study of broadly neutralizing antibodies to HIV, why most HIV-infected people do not make them, and the design of novel strategies to induce them with a vaccine.
Also, studying the earliest stages of HIV infection may shed light on ways to manipulate innate and mucosal immune responses to widen the window of opportunity for viral eradication, to prevent the virus from advancing to gut-associated lymphoid tissue, or both.
The authors conclude with cautious optimism that an effective HIV vaccine will be developed, but will depend on the significant growth of scientific understanding of HIV disease and human responses to the virus.