HLSC 2462U Lecture Notes - Lecture 6: Type Iv Hypersensitivity, Mast Cell, Blood Transfusion
Document Summary
Hypersensitivity alters response to an antigen that causes damage to the host. Mechanism that causes the disease (4 types) Autoimmunity response when own cells are under attack by autoantibodies or autoreactive t cells. When the immune response is not strong enough to protect the host, the host is immune deficient. Reactions require sensitization against an antigen that allows primary and secondary responses. Secondary response disease symptoms appear after that, 2 types, can be immediate or delayed. Delayed hypersensitivity reactions occurs hours to days after exposure. Antigen specific ige and products of mast cells. Most are environmental allergies (pollen, food, animals) Allergies are not just ige reactions and vice-versa. Short life span in the blood due to fc receptors on mast cells in which they degranulate to release histamine. Secondary exposure needs enough ige to sensitize mast cells: ige binds to fc receptors on mast cells, mast cell degranulates and releases histamine. Cells express antigens (tissue specific) placed on plasma membrane.
