In this article, we hope to analyze T-cells and HIV.
What are T-cells?
T-cells are a type of white blood cell that circulate around our bodies, scanning for cellular abnormalities and infections.
What is the role of T-cells in the immune system?
T-cells are essential for human immunity. The devastating effects of a lower than normal number of just one type of T-cell are all too evident in HIV/AIDS. There are several different kinds of T-cell; broadly speaking they can be divided into two different types, killer T-cells and helper T-cells. Killer T-cells have ‘X-ray vision’ as they are able to see inside our bodies own cells simply by scanning their surface. This mechanism allows killer T-cells to hunt down and destroy cells that are infected with germs or that have become cancerous. The other main type of T-cells are called helper T-cells. Helper T-cells orchestrate an immune response and play important roles in all arms of immunity.
It is important to study T-cells because:
Almost every aspect of the adaptive immune response is controlled, in some way, by T cells. These multifunctional cells have the ability to:
• Scan the intracellular environment for foreign invaders
• Directly kill virally or bacterially infected cells
• Naturally eradicate cancer cells
• Activate and help other immune cells that ingest germs or that make anti-infection molecules called antibodies
• Remember a germ that they encountered decades ago
Reasons why HIV has been such a difficult medical challenge
However, to comprehend the reasoning, you must first familiarize yourself with how HIV works.
HIV is a retrovirus, meaning that once it enters the body it infects T cells in the immune system and changes their genetic makeup, so that rather than protect the body as they are meant to, they now create more HIV. This eventually kills the body’s T cells in the process.
Once a patient’s T cell count drops to a certain number, he is considered as having AIDS. At this point, his immune system is no longer able to protect him against otherwise harmless infections and viruses.
The T cell count or CD4 count is like a snapshot of how well your immune system is functioning. CD4 cells (also known as CD4+ T cells) are white blood cells that fight infection. The more you have, the better. These are the cells that the HIV virus kills. As HIV infection progresses, the number of these cells declines. When the CD4 count drops below 200 due to advanced HIV disease, a person is diagnosed with AIDS. A normal range for CD4 cells is about 500-1,500. Usually, the CD4 cell count increases as the HIV virus is controlled with effective HIV treatment.