The immune system is responsible for recognizing and responding to foreign substances, such as bacteria, viruses, and toxins, to protect the body from infection and disease.

Adaptive immunity is responsible for recognizing and attacking specific pathogens through the production of antibodies and the activation of cytotoxic T cells.

Antibodies play a crucial role in the immune response by destroying infected cells, activating complement proteins, and neutralizing toxins.

B cells are responsible for producing antibodies, which are proteins that recognize and bind to specific antigens.

T cells play a crucial role in the immune response by destroying infected cells, activating B cells, and providing help to other immune cells.

Innate immunity is faster to respond than adaptive immunity because it does not require the activation and differentiation of immune cells.

The complement system helps antibodies bind to antigens by forming a complex that can be recognized by phagocytes.

Autoimmune diseases are characterized by the production of autoantibodies, which are antibodies that target the body's own tissues.

Rheumatoid arthritis is the most common type of autoimmune disease, affecting approximately 1% of the population.

MHC molecules present antigens to T cells, which allows the T cells to recognize and respond to the antigens.

MHC class I molecules are responsible for presenting antigens to CD8+ T cells.

Cytokines play a crucial role in the immune response by activating immune cells, suppressing immune responses, and regulating the differentiation of immune cells.

Interferon-gamma, tumor necrosis factor-alpha, and interleukin-1 are all cytokines that can activate macrophages.

The thymus is responsible for maturing T cells, which are essential for the adaptive immune response.

Neutrophils, macrophages, and dendritic cells are all phagocytes, which means they can engulf and destroy foreign particles.