Introduction to the immune system

Anmerkungen:

• Immunity: Resistance to diseases Immune system: Cells, tissues and mediators Coordinated Reactions: Immune response

Anmerkungen:

• Defence against infections Recognise and respond to foreign proteins Defence against tumours Antibodies are highly specific reagents for detecting any class of antigens

1. Implications

   Anmerkungen:

   • Without immune system, it increases susceptibility to infections, vaccination boosts immune defence Barrier to transplantation and gene therapy Immune evasion, immunotherapy Immunological approach for lab used in clinical and research 

Anmerkungen:

• Hypersensitivity/T cell mediatd diseases

Anmerkungen:

• Innate Immunity vs Adaptive immunity

1. Innate immunity

   Anmerkungen:

   • Dendritic Cell Mast Cell Macrophage Natural Killer cell Complement Proteins Granulocytes
   1. Flowchart

      Anmerkungen:

      • Toll-like receptors leads to production of cytokines: ROS (reactive oxygen species) and it leads to killing to microbes The N-formyl methionyl receptors allows increase in adhesion of blood/microbes and it aids in migration into tissues Mannose receptors increases phagocytosis of microbes to phagosome and leads to killing of microbes.
      1. Outcomes
         1. Possible Defects

            Anmerkungen:

            • Congenital defects (i.e immunity defects) Acquired defects: like irradiation and chemotherapy Evasion by Microbes: Resistance to phagocytosis and the immune system
2. Adaptive Immunity

   Anmerkungen:

   • B Cells (generate antibodies) T Cells and the daughter T cells.
   1. Flowchart

      Anmerkungen:

      • 2 possible scenarios: Humoral immunity or cell mediated immunity THe antigen can react with B lymphocytes or macrophages and hence it produces reaction within the B lymphocyte to "memorize" and to secrete antibodies The T-helper cell, makes memory and help to kill cells.
   2. Properties

      Anmerkungen:

      • Specific receptor/co receptor expression Generation of cells with long life span due to ability to 'clone' Selective proliferation and differentaition of antigen specific lymphocytes Elimination of self reactive cells by clonal detection : Tolerance.
   3. B-Cells

      Anmerkungen:

      • Recognise through Anitbody binding, to eliminate extracellular pathogens. It then activate the cell to divide and release more antibody antibody then cirulates to bind to surface of bugs then it alerts/primes the organism is foreign and it allows the complement to bind and destroy cell and block pathogen and neutralize toxins.
   4. T-Cells

      Anmerkungen:

      • It phagocytosed microbes in macrophages intracellular microbes replicate within the cells and the T-cells recognise small parts on the surface of HOST cells
      1. CD8

         Anmerkungen:

         • Peptides on MHC class 1 Peptides from inside cells Kill cells
      2. CD4

         Anmerkungen:

         • Peptides on MHC class II Peptides from outside Leads to help.
3. Mechanisms

   Anmerkungen:

   • As time passes, the innate immunity will switch to adaptive immunity and back and forth if needed.
4. Comparison

   Anmerkungen:

   • Specificity: Innate has class shared by class of microbes, not that specific Adaptive immunity recognise specific microbial antigens or nonmicrobial antigens Receptors: Innate immunty, react to receptors encoded in the germline Adaptive: Encoded by genes, highly sophisticated Distribution: Innate immunity: Nonclonal Adaptive immunity: Clonal