CD4lymfosyyttejä

CD4-lymfosyytit, also known as T-helper-solut, are a type of white blood cell crucial for the immune system's function. They are a subtype of T-lymphocytes, characterized by the presence of a CD4 protein on their cell surface. These cells play a central role in orchestrating the immune response by helping to activate and direct other immune cells, such as B-cells and cytotoxic T-cells.

Upon encountering an antigen, a CD4-lymfosyytti becomes activated and can differentiate into various subtypes, each with specific functions. For example, Th1 cells are important for cell-mediated immunity against intracellular pathogens, while Th2 cells are involved in humoral immunity and defense against extracellular parasites. Th17 cells contribute to immunity against extracellular bacteria and fungi, and regulatory T cells (Tregs) help to suppress immune responses and maintain self-tolerance, preventing autoimmune diseases.

The number of CD4-lymfosyytit in the blood is a key indicator of immune system health. In conditions like HIV/AIDS, the human immunodeficiency virus (HIV) primarily targets and destroys CD4-lymfosyytit, leading to a severely weakened immune system and increased susceptibility to opportunistic infections. Monitoring CD4 counts is therefore essential in the management of HIV infection and other immunodeficiency disorders. Research continues to explore the complex roles of CD4-lymfosyytit in various physiological and pathological processes.