The immune system is the body’s best defense in battling diseases like HIV and cancer. Presently, an international team of analysts is bridling the immune system to reveal new clues that may help in efforts to produce an HIV vaccine.
SFU professor Mark Brockman and co-authors from the University of KwaZulu-Natal in South Africa have recognized an association between infection control and how well antiviral T cells respond to diverse HIV sequences.
Brockman explains that HIV adapts to the human immune system by altering its sequence to evade helpful antiviral T cells.
“So to develop an effective HIV vaccine, we need to generate host immune responses that the virus cannot easily evade,” he says.
Brockman’s group has grown new laboratory-based method for distinguishing antiviral T cells and surveying their ability to recognize diverse HIV sequences.
“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.”
Distinguishing the T cells that attack HIV antigens sounds simple, yet Brockman says three biological factors are critical to a T cell-mediated immune reaction. Also, in HIV infection, all three are highly genetically diverse.
He explains that for a T cell to perceive a peptide antigen, the antigen should initially be displayed on the cell surface by human leukocyte antigen proteins (HLA), which are inherited.
And, since many thousands of possible HLA variants exist in the human population, each individual reacts differently to infection. Furthermore, since HIV is very different andevolves constantly during untreated infection, the peptide antigen sequence also changes.
Coordinating T cells against the HLA variations and HIV peptide antigens expressed in a critical step in the routine research process Yet, 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 evaluated that an person’s T cell “repertoire” is comprised of a conceivable 20-100 million unique lineages of cells that can be recognized by their T cell receptors (TCR), of which just a few of will be important in responding to a specific antigen.
So to decrease the study’s complexity, the team analyzed two exceedingly related HLA variations (B81 and B42) that perceive a similar HIV peptide antigen (TL9) however are related with various clinical outcomes following infection.
By seeing how well individual T cells perceived TL9 and diverse TL9 sequence variations that occur in circulating HIV strains, the specialists found that T cells from people who expressed HLA B81 recognized more TL9 variants compared to T cells from people who expressed HLA B42.
Strikingly, a gathering of T cells in some B42-communicating people showed a more prominent capacity to perceive TL9 sequence variants. The presence of these T cells was associated with better control of HIV infection.
This study exhibits that individual T cells contrast generally in their capacity to perceive peptide variations and suggests that these differences may be clinically significant in the context of a diverse or rapidly evolving pathogen such as HIV.
Much work should be done to make a successful antibody. Be that as it may, says Brockman, “Complete techniques to evaluate the capacity of T cells to perceive assorted HIV arrangements, for example, those announced in this examination, give basic data to encourage plan and test new antibody procedures.”
