Final answer:
T cells, also known as T lymphocytes, are a type of white blood cell that play a critical role in the immune system. They can be categorized into subsets such as killer T cells, helper T cells, regulatory T cells, and memory T cells. Flow cytometry is commonly used to quantify the concentration of T cells in a patient's blood and assess their immune status.
Step-by-step explanation:
T cells, also known as T lymphocytes, are a type of white blood cell that plays a crucial role in the immune system. They are responsible for recognizing and destroying cells infected with pathogens or cancerous cells. T cells can be further categorized into different subsets, such as killer T cells, helper T cells, regulatory T cells, and memory T cells.
For example, killer T cells (also known as cytotoxic T cells) specifically target and destroy cells that are infected with viruses or cancerous. They do this by releasing toxic proteins that induce cell death in the target cells. On the other hand, helper T cells release cytokines that control the immune response and coordinate the activities of other immune cells.
To quantify the concentration of T cells in a patient's blood, flow cytometry is commonly used. This technique involves labeling T cells with specific molecules, such as CD4 or CD8, and analyzing their fluorescence using a flow cytometer. The results can provide valuable information about the patient's immune status and help guide treatment decisions.