UT researchers discover weakness in HIV virus that may enable vaccine
Scientists hope for successful vaccine within next 10 years
By: Ashley Crooks
Posted: 7/24/08
Researchers at the University of Texas Health Science Center at Houston have discovered a quirk in the constantly-evolving HIV virus that they say will help them to develop an effective vaccine for the prevention of the virus in the next 10 years.
"It is a long road; the virus has been around for almost 25 years, vaccine efforts have failed again and again, but we think we have a unique solution to the problem," said Sudhir Paul, a UT medical school pathology professor who has worked to find an effective combatant to the HIV virus for the past 19 years.
Along with fellow researchers, Paul has identified one region on the surface of the virus that is mostly unchanging. He explained that this small region is critical for the virus to bind to cells; without this section, the virus would not be able to infect the cells.
The UT researchers call this small region the "Achilles heel" of HIV, which causes AIDS.
"We identified this region as a suitable target for antibodies," Paul said.
The ever-changing virus evades the antibodies created by the human immune system, preventing the body from defending itself. Antibodies that can recognize the unchanging region of the virus can block the infection, Paul said.
He said antibodies normally have a limited ability to defend against an infection because one antibody molecule blocks only one virus particle. Paul and his research team have identified abzymes, which are a form of antibody that can catalyze the breakdown of many virus particles.
The specific abzyme identified by researchers recognizes the "Achilles heel" of HIV, allowing it to attack the virus.
Researchers identified abzymes both in patients with lupus, a disease in which the body's immune system attacks organs, and in patients who have lived with HIV for long periods of time without treatment.
The researchers obtained some abzymes from HIV-positive and lupus patients and cloned them by protein engineering methods in order to procure amounts large enough for potential use in a vaccine or a topical treatment.
The researchers will use the findings to conduct clinical trials in the future, Paul said.
In clinical trials, the researchers will determine how abzymes can be used to eradicate HIV in patients who are already infected or to apply directly to the skin to prevent sexual transmission of the virus. The abzymes can also be used to develop a preventative vaccine.
Paul said he believes the creation of a vaccine is the most important application of the research because it is the only way to eradicate the virus all together. When a candidate vaccine was given to animals in test trials, an animal's immune system generated the crucial abzyme to combat the virus, Paul said.
This vaccine would be drastically different from current HIV treatments, which are used to block some parts of the virus' life cycle. Current treatments can have severe side effects, including toxicity, and 15 percent of patients are resistant to them, he said.
"Moreover, these drugs are not affordable, particularly for the third world," Paul said. "We need a cheap preventative vaccine that will take care of the virus from birth to death."
Paul said the federal government has been financially supporting the group of researchers for over a decade, but in order to move forward with the clinical trials, they will need the support of the private sector. He said when the researchers can get financial backing from a private company, development of the vaccine will follow.
"I am very optimistic that we will have a vaccine by the time I turn 65," said Paul, who is 55 years old.
Scientists hope for successful vaccine within next 10 years
By: Ashley Crooks
Posted: 7/24/08
Researchers at the University of Texas Health Science Center at Houston have discovered a quirk in the constantly-evolving HIV virus that they say will help them to develop an effective vaccine for the prevention of the virus in the next 10 years.
"It is a long road; the virus has been around for almost 25 years, vaccine efforts have failed again and again, but we think we have a unique solution to the problem," said Sudhir Paul, a UT medical school pathology professor who has worked to find an effective combatant to the HIV virus for the past 19 years.
Along with fellow researchers, Paul has identified one region on the surface of the virus that is mostly unchanging. He explained that this small region is critical for the virus to bind to cells; without this section, the virus would not be able to infect the cells.
The UT researchers call this small region the "Achilles heel" of HIV, which causes AIDS.
"We identified this region as a suitable target for antibodies," Paul said.
The ever-changing virus evades the antibodies created by the human immune system, preventing the body from defending itself. Antibodies that can recognize the unchanging region of the virus can block the infection, Paul said.
He said antibodies normally have a limited ability to defend against an infection because one antibody molecule blocks only one virus particle. Paul and his research team have identified abzymes, which are a form of antibody that can catalyze the breakdown of many virus particles.
The specific abzyme identified by researchers recognizes the "Achilles heel" of HIV, allowing it to attack the virus.
Researchers identified abzymes both in patients with lupus, a disease in which the body's immune system attacks organs, and in patients who have lived with HIV for long periods of time without treatment.
The researchers obtained some abzymes from HIV-positive and lupus patients and cloned them by protein engineering methods in order to procure amounts large enough for potential use in a vaccine or a topical treatment.
The researchers will use the findings to conduct clinical trials in the future, Paul said.
In clinical trials, the researchers will determine how abzymes can be used to eradicate HIV in patients who are already infected or to apply directly to the skin to prevent sexual transmission of the virus. The abzymes can also be used to develop a preventative vaccine.
Paul said he believes the creation of a vaccine is the most important application of the research because it is the only way to eradicate the virus all together. When a candidate vaccine was given to animals in test trials, an animal's immune system generated the crucial abzyme to combat the virus, Paul said.
This vaccine would be drastically different from current HIV treatments, which are used to block some parts of the virus' life cycle. Current treatments can have severe side effects, including toxicity, and 15 percent of patients are resistant to them, he said.
"Moreover, these drugs are not affordable, particularly for the third world," Paul said. "We need a cheap preventative vaccine that will take care of the virus from birth to death."
Paul said the federal government has been financially supporting the group of researchers for over a decade, but in order to move forward with the clinical trials, they will need the support of the private sector. He said when the researchers can get financial backing from a private company, development of the vaccine will follow.
"I am very optimistic that we will have a vaccine by the time I turn 65," said Paul, who is 55 years old.
