Some autoimmune disorders are thought to be caused by _________, which occurs when an infectious agent is composed of antigens with the same amino acid sequences as the body's self antigens, resulting in the immune system attacking normal tissue with the similar composition.

Some autoimmune disorders are thought to be caused by molecular mimicry, which occurs when an infectious agent is composed of antigens with the same amino acid sequences as the body's self antigens, resulting in the immune system attacking normal tissue with the similar composition.

• Autoimmune disorders occur when the body's immune system mistakenly attacks its own tissues, mistaking them for foreign invaders. Normally, the immune system has the ability to distinguish between foreign cells and its own cells. However, in molecular mimicry, the immune system recognizes a sequence of amino acids in the proteins of a pathogen that are similar to those in the body's own proteins. When the immune system tries to defend the body against this pathogen, it inadvertently attacks the body's own tissues as well.
• This case of mistaken identity can lead to inflammation and damage in various tissues and organs, depending on where the similar proteins are found in the body. Common examples of autoimmune diseases that may involve molecular mimicry include rheumatic fever (where streptococcal bacteria have similar antigens to heart, joints, and other tissues), and multiple sclerosis (where a viral infection may trigger an immune response against myelin, a component of nerve cells). Understanding molecular mimicry is an important area of research as it offers insights into the cause and possible treatments for autoimmune diseases.