Currently, there are no such medications which can completely treat deadly diseases like HIV. Human’s immune system can be classified as the best body defense mechanism to fight diseases like cancer and HIV. The researchers are currently studying and working on the immune system in order to develop some effective vaccines for HIV. SFU professor Mark Brockman and co-authors from the University of KwaZulu-Natal in South Africa observed an amazing link between the manifestation control and the response of T cells to different HIV sequences.
Brockman found out that HIV is capable of altering its sequence so that it can easily adapt to the immune system while escaping from beneficial T cells. He said: “So to develop an effective HIV vaccine, we need to generate host immune responses that the virus cannot easily evade.” Brockman and his team are working on discovering new laboratory methods to identify and study the function and ability of T cells more carefully.
“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 tumors.”
One of an easy task for the researchers is to identify the T cells which have the ability to attack HIV antigens but Brockman explained that there are three important factors which play an important role in the cell-mediated response of the T cells.
In the case of HIV, all of these three biological factors vary highly genetically. For the T cells, first, the antigen must be present on the human cell surface. This process is directed by human leukocyte antigen proteins (HLA). These antigen proteins are inherited. There is a great variety of HLA in human populace thus each and every person reacts differently to infections.
One of the most significant and hard steps was to match the T cells with HIV peptide antigens and HLA variants expressed differently in every person. Brockman explained, “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.”
According to the research, a person’s T cells –repertoire- is a complex substance made up of 20 to 100 unique combinations of cells that can only be identified by its T cell receptors (TCR). Only some of these are successful in responding to the specific antigens. So to make the things easier researchers choose two HLA variants (B81 and B42). Both of these HLA variants attacks the same TL9 peptide antigen, however, both of them are the result of different clinical trials.
The researchers worked to know which T cells are more effective in recognizing TL9 and other HIV strains. As per the analysis, People who expressed HLA B81 were able to identify more TL9 variants than B42. The T cells showing HLA B81 variant are more able to control the HIV infection. Each and every person’s body is different in terms of many factors including the ability of the T cells to recognize peptide variants.
Due to this great diversity, it is easy for the pathogens like HIV to develop. The researchers say that much more work is still needed in order to produce an effective vaccine for HIV. 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.”