Final answer:
Immune reactions to cattle-derived insulin occur because bovine insulin's slightly different composition can trigger the production of antibodies, leading to autoimmunity. Recombinant DNA technology has allowed the production of human insulin, reducing the risk of these reactions. Molecular mimicry is also a key concept in understanding autoimmunity related to insulin.
Step-by-step explanation:
Some people have immune reactions to insulin derived from cattle because bovine insulin, while similar to human insulin, has a slightly different composition. This difference can trigger the immune system of some patients with Type 1 diabetes to produce antibodies against the animal insulin, leading to inflammatory responses at the injection site. This reaction is a form of autoimmunity where the body's immune system reacts to a normally harmless substance.
In order to prevent these immune reactions, scientists have used recombinant DNA technology to produce human insulin in bacteria like E. coli. This technological advance means that the insulin produced is chemically identical to that produced naturally in humans, thereby greatly reducing the risk of immune reactions. It also has led to the availability of synthetic human insulin, commonly known as humulin.
The concept of molecular mimicry is important in understanding autoimmunity, where immune receptors such as antibodies and T-cell receptors bind to self-antigens that are structurally similar to pathogen antigens. This can lead to disorders like autoimmune rheumatic fever or Type 1 diabetes mellitus, which is characterized by a destructive inflammatory response against pancreatic cells producing insulin.