Which statement about foreign antigens is true?

Which statement about foreign antigens is true?

• A. They are quickly recognized as self
• B. They may induce an autoimmune reaction
• C. They are only produced by viral infections
• D. They cause the body to respond only once

Answer: (B)

The statement regarding foreign antigens inducing an autoimmune reaction is accurate. Foreign antigens are substances that are recognized by the immune system as non-self, such as proteins from pathogens (bacteria, viruses, fungi) or allergens from environmental sources. In some cases, the immune system may mistakenly target the body's own tissues as foreign due to similarities between self-antigens and foreign antigens or due to aberrant immune responses. This misrecognition can lead to autoimmune diseases, where the body's immune response damages its own cells and tissues. The other statements do not hold true in the context of foreign antigens. They are not quickly recognized as self; rather, they are typically identified by the immune system as invaders that need to be attacked. Additionally, foreign antigens are not exclusively produced by viral infections, as they can originate from various sources, including bacteria, allergens, and other microorganisms. Lastly, foreign antigens can lead to a robust immune response that is not limited to a single occurrence; the immune system can respond multiple times to the same antigen, especially in cases where memory cells are involved, allowing for more efficient responses upon re-exposure.

The statement regarding foreign antigens inducing an autoimmune reaction is accurate. Foreign antigens are substances that are recognized by the immune system as non-self, such as proteins from pathogens (bacteria, viruses, fungi) or allergens from environmental sources. In some cases, the immune system may mistakenly target the body's own tissues as foreign due to similarities between self-antigens and foreign antigens or due to aberrant immune responses. This misrecognition can lead to autoimmune diseases, where the body's immune response damages its own cells and tissues.

The other statements do not hold true in the context of foreign antigens. They are not quickly recognized as self; rather, they are typically identified by the immune system as invaders that need to be attacked. Additionally, foreign antigens are not exclusively produced by viral infections, as they can originate from various sources, including bacteria, allergens, and other microorganisms. Lastly, foreign antigens can lead to a robust immune response that is not limited to a single occurrence; the immune system can respond multiple times to the same antigen, especially in cases where memory cells are involved, allowing for more efficient responses upon re-exposure.