What is the role of antibodies in type 2 hypersensitivity reactions?

What is the role of antibodies in type 2 hypersensitivity reactions?

• A. They bind to antigens and activate T-cells
• B. They form immune complexes that deposit in tissues
• C. They activate mast cells and release histamine
• D. They bind to self-antigens, leading to tissue destruction

Answer: (D)

In type 2 hypersensitivity reactions, the primary role of antibodies is to bind to specific self-antigens on the surface of cells. This interaction can trigger a series of immunological responses that ultimately lead to tissue damage or destruction. When antibodies, typically of the IgG or IgM class, bind to these self-antigens, they can initiate complement activation or attract immune cells that contribute to inflammation. This process can result in various pathological effects, including opsonization (marking cells for destruction), antibody-dependent cell-mediated cytotoxicity (ADCC), or complement-mediated lysis of the target cells. Consequently, the presence of these antibodies leads to an attack against the body’s own tissues, which is characteristic of type 2 hypersensitivity. Conditions such as autoimmune hemolytic anemia or Goodpasture's syndrome exemplify this mechanism, where the immune system mistakenly targets self-components, causing tissue damage and functional impairment. This understanding emphasizes the crucial role antibodies play in mediating destructive immune responses in type 2 hypersensitivity.

In type 2 hypersensitivity reactions, the primary role of antibodies is to bind to specific self-antigens on the surface of cells. This interaction can trigger a series of immunological responses that ultimately lead to tissue damage or destruction.

When antibodies, typically of the IgG or IgM class, bind to these self-antigens, they can initiate complement activation or attract immune cells that contribute to inflammation. This process can result in various pathological effects, including opsonization (marking cells for destruction), antibody-dependent cell-mediated cytotoxicity (ADCC), or complement-mediated lysis of the target cells.

Consequently, the presence of these antibodies leads to an attack against the body’s own tissues, which is characteristic of type 2 hypersensitivity. Conditions such as autoimmune hemolytic anemia or Goodpasture's syndrome exemplify this mechanism, where the immune system mistakenly targets self-components, causing tissue damage and functional impairment.

This understanding emphasizes the crucial role antibodies play in mediating destructive immune responses in type 2 hypersensitivity.