Question

Immune responses often display "exquisite specificity." However, cross-reactions can occur. Describe the classic example that includes rheumatic fever.

Answer 1

Cross-reactivity in immune responses can result in autoimmune diseases such as rheumatic fever, where antibodies against Streptococcus bacterial proteins mistakenly attack heart tissues.

Step-by-step explanation:

Immune responses display exquisite specificity, but cross-reactions do occur, such as in the case of rheumatic fever. This autoimmune reaction follows infection with Streptococcus bacteria, causing antibodies to the pathogen's M protein to cross-react with heart myosin. This immune response, initially protective, turns damaging as it attacks the heart instead, leading to severe complications when mistakenly targeting the body's own tissues.