Final answer:
The correct answer is a) Benefits include enhanced immune response; costs include autoimmunity. Antibody cross-reactivity can bolster the immune response by recognizing similar pathogens, but may also lead to autoimmune diseases if antibodies target the body's own tissues.
Step-by-step explanation:
The benefits and costs of antibody cross-reactivity include a mix of enhanced immune protection but also the potential for detrimental autoimmune responses. The correct option for the benefits and costs of antibody cross-reactivity is: a) Benefits include enhanced immune response; costs include autoimmunity.
Antibodies are fundamental to the adaptive immune system's ability to recognize a wide array of pathogens. They are specific and versatile enough to develop an immense variety of receptors, estimated at around 100 trillion, to target nearly any pathogen.
One significant advantage of cross-reactivity is that antibodies can recognize and neutralize similar pathogens, providing an enhanced immune response without the need for prior exposure to each specific pathogen. For example, antibodies developed against one strain of Gram-negative bacteria may cross-react and offer protection against related strains.
However, there are drawbacks. Antibodies that cross-react with self-antigens can cause the immune system to mistakenly attack the body's own cells, leading to autoimmunity. A well-known example of an autoimmune disorder is systemic lupus erythematosus (SLE), where antibodies initially targeting microorganism nucleic acids cross-react with the person's own DNA.
This phenomenon of cross-reactivity underscores the fine balance the immune system must maintain between being sufficiently aggressive against pathogens while avoiding harm to the host organism.