Immuunireaktio

Immuunireaktio, also known as an immune response, is the body's defense mechanism against harmful substances, such as pathogens like bacteria, viruses, and fungi, as well as damaged or abnormal cells. This process is orchestrated by the immune system, which includes various cells, tissues, and organs that work together to identify and neutralize threats.

The immune response can be broadly categorized into two types: innate immunity and adaptive immunity. Innate immunity is the body's first line of defense, providing immediate but non-specific protection. It involves physical barriers like skin and mucous membranes, as well as cells and proteins that can quickly recognize and destroy pathogens. Adaptive immunity, on the other hand, is more specific and tailored to each individual. It involves lymphocytes, particularly T cells and B cells, which can recognize and remember specific pathogens, providing long-lasting protection.

The immune response typically involves several stages. Upon encountering a pathogen, immune cells called antigen-presenting cells (APCs) process the pathogen and present fragments of it on their surface using major histocompatibility complex (MHC) molecules. This allows T cells to recognize and respond to the pathogen. Activated T cells can then help other immune cells, such as B cells and macrophages, to eliminate the pathogen.

In some cases, the immune response can lead to an allergic reaction or autoimmune disease. Allergic reactions occur when the immune system overreacts to a normally harmless substance, while autoimmune diseases involve the immune system attacking the body's own tissues. Understanding the mechanisms of the immune response is crucial for developing effective treatments for various diseases and conditions.