An association between infection control and how well antiviral T cells respond to diverse HIV sequences has been discovered by SFU professor Mark Brockman and co-authors from the University of KwaZulu-Natal in South Africa.
The immune system is the body's best defense in fighting diseases like HIV and cancer. Now, an international team of researchers is harnessing the immune system to reveal new clues that may help in efforts to produce an HIV vaccine.
AIDS/HIV
"AIDS is an epidemic disease, a potentially preventable, deadly infection for which there is no cure, no vaccine, and it is not under control." - National Commission on AIDS, 1993.
Advertisement
‘HIV adapts to the human immune system by altering its sequence to evade helpful antiviral T cells.’
Tweet it Now
"So to develop an effective HIV vaccine, we need to generate host immune responses that the virus cannot easily evade," he says.
Brockman's team has developed new laboratory-based methods for identifying antiviral T cells and assessing their ability to recognize diverse HIV sequences.
![Quiz on HIV / AIDS]( "Quiz on HIV / AIDS")
Statistics tell us that the world HIV+ population has risen drastically from 8 million in 1990 to a whopping 33 million in 2007! Even more alarming is the fact that young people (below the age of 25) account for half of these infections! This is adequate proof for the lack of awareness among the general public even in these modern times. So take our quiz and brush up on the essential facts of HIV/
"T cells are white blood cells that can recognize foreign particles called peptide antigens," says Brockman. "There are two major types of T cells--those that 'help' other cells of the immune system, and those that kill infected cells and tumours."
Identifying the T cells that attack HIV antigens sounds simple, but Brockman says three biological factors are critical to a T cell-mediated immune response. And in HIV infection, all three are highly genetically diverse.
He explains that for a T cell to recognize a peptide antigen, the antigen must first be presented on the cell surface by human leukocyte antigen proteins (HLA), which are are inherited.
And since many thousands of possible HLA variants exist in the human population, every person responds differently to infection. In addition, since HIV is highly diverse and evolves constantly during untreated infection, the peptide antigen sequence also changes.
Matching T cells against the HLA variants and HIV peptide antigens expressed in an individual is a critical step in the routine research process. But, says Brockman, "our understanding of T cell responses will be incomplete until we know more about the antiviral activity of individual T cells that contribute to this response."
It is estimated that a person's T cell "repertoire" is made up of a possible 20-100 million unique lineages of cells that can be distinguished by their T cell receptors (TCR), of which only a few will be important in responding to a specific antigen.
So to reduce the study's complexity, the team examined two highly related HLA variants (B81 and B42) that recognize the same HIV peptide antigen (TL9) but are associated with different clinical outcomes following infection.
By looking at how well individual T cells recognized TL9 and diverse TL9 sequence variants that occur in circulating HIV strains, the researchers found that T cells from people who expressed HLA B81 recognized more TL9 variants compared to T cells from people who expressed HLA B42.
Notably, a group of T cells in some B42-expressing individuals displayed a greater ability to recognize TL9 sequence variants. The presence of these T cells was associated with better control of HIV infection.
This study demonstrates that individual T cells differ widely in their ability to recognize peptide variants and suggests that these differences may be clinically significant in the context of a diverse or rapidly evolving pathogen such as HIV.
Much work needs to be done to create an effective vaccine. However, says Brockman, "Comprehensive methods to assess the ability of T cells to recognize diverse HIV sequences, such as those reported in this study, provide critical information to help design and test new vaccine strategies."
Source: Eurekalert
Quiz on HIV / AIDS
Statistics tell us that the world HIV+ population has risen drastically from 8 million in 1990 to a whopping 33 million in 2007! Even more alarming is the fact that young people (below the age of 25) account for half of these infections! This is adequate proof for the lack of awareness among the general public even in these modern times. So take our quiz and brush up on the essential facts of HIV/
Advertisement
"T cells are white blood cells that can recognize foreign particles called peptide antigens," says Brockman. "There are two major types of T cells--those that 'help' other cells of the immune system, and those that kill infected cells and tumours."
Identifying the T cells that attack HIV antigens sounds simple, but Brockman says three biological factors are critical to a T cell-mediated immune response. And in HIV infection, all three are highly genetically diverse.
He explains that for a T cell to recognize a peptide antigen, the antigen must first be presented on the cell surface by human leukocyte antigen proteins (HLA), which are are inherited.
And since many thousands of possible HLA variants exist in the human population, every person responds differently to infection. In addition, since HIV is highly diverse and evolves constantly during untreated infection, the peptide antigen sequence also changes.
Matching T cells against the HLA variants and HIV peptide antigens expressed in an individual is a critical step in the routine research process. But, says Brockman, "our understanding of T cell responses will be incomplete until we know more about the antiviral activity of individual T cells that contribute to this response."
It is estimated that a person's T cell "repertoire" is made up of a possible 20-100 million unique lineages of cells that can be distinguished by their T cell receptors (TCR), of which only a few will be important in responding to a specific antigen.
So to reduce the study's complexity, the team examined two highly related HLA variants (B81 and B42) that recognize the same HIV peptide antigen (TL9) but are associated with different clinical outcomes following infection.
By looking at how well individual T cells recognized TL9 and diverse TL9 sequence variants that occur in circulating HIV strains, the researchers found that T cells from people who expressed HLA B81 recognized more TL9 variants compared to T cells from people who expressed HLA B42.
Notably, a group of T cells in some B42-expressing individuals displayed a greater ability to recognize TL9 sequence variants. The presence of these T cells was associated with better control of HIV infection.
This study demonstrates that individual T cells differ widely in their ability to recognize peptide variants and suggests that these differences may be clinically significant in the context of a diverse or rapidly evolving pathogen such as HIV.
Much work needs to be done to create an effective vaccine. However, says Brockman, "Comprehensive methods to assess the ability of T cells to recognize diverse HIV sequences, such as those reported in this study, provide critical information to help design and test new vaccine strategies."
Source: Eurekalert
Surgery Kills More Than HIV, TB, Malaria Combined: Study
Every year, million people die worldwide after surgery than from HIV, TB, and malaria combined, finds a new study.
Advertisement
Advertisement
|
Advertisement
Recommended Reading
Latest AIDS/HIV News
In India, annual HIV infections and AIDS-related deaths continue to drop. Between 2010 and 2021, new HIV infections dropped by 46%.
Globally, all countries have promised to end AIDS by 2030, for which it is essential to safeguard individuals living with HIV to complete HIV care services.
How can you prevent HIV while breastfeeding? A monthly vaginal ring containing the antiretroviral drug dapivirine safely prevents HIV infection while breastfeeding.
Union Minister of State for Health Bharti Pravin Pawar had said that the government is providing free lifelong antiretroviral (ARV) medicines for people living with HIV.
Dr. Korosi said the goal to end AIDS by 2030 is badly off track, as inequalities, discrimination, and disregard for human rights are hampering our progress.