Question

Despite the immune system's ability to recognize and respond to various proteins or antigens, why do self-antigens remain untargeted by the immune system?

A) Self-antigens exhibit structural features that make them invisible to immune cells, preventing recognition.

B) The immune system is inherently programmed to distinguish between self and non-self, sparing self-antigens from attack.

C) Self-antigens lack specific markers recognized by the immune system, ensuring their non-reactivity.

D) Immune cells possess a specialized mechanism that actively suppresses responses to self-antigens, preventing immune attack on the body's own tissues.

Answer 1

The immune system has specialized mechanisms to actively suppress immune responses to self-antigens, preventing immune attack on the body's own tissues. These mechanisms involve the selection for weakly self-binding cells during T and B lymphocyte maturation, as well as populations of T cells that suppress the immune response to self-antigens and inhibit the secretion of immune factors. These mechanisms of immune tolerance protect the body from autoimmune diseases.

Step-by-step explanation:

The immune system is able to recognize and respond to various proteins or antigens, including self-antigens, which are normally present in the body. However, self-antigens remain untargeted by the immune system due to specialized mechanisms that actively suppress immune responses to them. These mechanisms help prevent the immune system from attacking the body's own tissues, which could lead to autoimmune diseases.

One of the primary mechanisms of immune tolerance is the selection for weakly self-binding cells during T and B lymphocyte maturation. Additionally, there are populations of T cells that suppress the immune response to self-antigens and inhibit the secretion of immune factors that would stimulate an immune attack on self-antigens. This suppression of immune responses to harmless macromolecules is highly regulated and prevents processes that could be damaging to the host.

These mechanisms of immune tolerance allow the immune system to focus on targeting non-self antigens, such as those found on pathogens, while avoiding unnecessary and potentially harmful immune responses against self-antigens.