Question

Briefly discuss the role of the immune system in pathogenesis.

Answer 1

   Immune system is a protective and defence mechanism of body. It protects cells and tissue by foreign pathogens like bacteria, viruses and other antigens. Different pathways and cells are generated during embryogenesis for the development of immune system. Different types of cells like T cells, B cells, killer cells, cytokines are secreted during the activation of immune system. Additionally, different macromolecules as like, cell receptors, MHC molecules, interleukins and other peptides present on cell surface or circulates in body, involve in immune responds. Collectively immune system is very complex systems with different pathways and Many molecules/cells involve in immune system. Based on types of cells and molecules involve, it is divided into humoral immune system and cell mediated immune system

   In humoral immunity, macromolecules, antibodies, antimicrobial proteins and several peptides are circulating in extracellular fluid. As it detects specific type of antigen, it generates immune responds.

   In cell mediated immunity, several cytokines are released in responds to specific antigens by different type of cells (phagocytes, cytotoxic T lymophytes ).

In general the role of immune system in pathogenesis is as followed:

• Foreign antigen is present on the cell surface.
• It is engulfed by the process of phagocytosis and surrounded by phagocytic vesicles.
• Lysosomes helps phagocytic vesicles to fragment the antigen.
• Now macrophages helps antigen molecules to present at MHC. MHC molecules are present on the surface of cell which recognise the antigen molecules.
• This complex activates T helper cells which secretes interleukin molecules and activates B cell to secrete antibody . antobody bids to antigen and destroy it. T memory cells creates a memory for presentation of that antigen in future, hence if this antigen affects in future, it will directly generates antibody against that particular antigen.