Understanding Immune Tolerance: Discriminating Self from Non-Self

The video introduces immune tolerance as a mechanism that helps the immune system differentiate between self and non-self antigens. It explains how the generation of diversity in immune cells can lead to receptors that target host cells, and tolerance prevents this.

Immune tolerance allows the immune system to discriminate between self and non-self. The presenter references work by Bernett and Peter in the 1960s, for which they won the Nobel Prize. Developing B and T cells undergo testing to ensure non-responsiveness to host structures.

The video introduces the danger hypothesis, which suggests that the immune system evaluates new encounters based on their potential danger to the host rather than simply distinguishing between self and non-self. Cell death, whether from natural processes or damage, releases danger signals that can activate the immune system.

A robust self-tolerance can have unintended consequences, such as the immune system ignoring cancerous cells that express self-structures. Dysfunctional tolerance is the root cause of autoimmune diseases. Failure in tolerance can lead to hypersensitivity and immune deficiencies.

Simply, tolerance differentiates between self and non-self, acting on the latter to activate the immune system and neutralize harmful structures while avoiding interaction with self structures to prevent autoimmune diseases.