|Cell-Mediated Immune Response|
- T cells formed in the blood marrow circulate in the blood circulatory system until it reaches the thymus glands.
- In thymus glands, T cells differentiate to form T helper cells and T cytotoxic cells, each with a unique type of T cell receptor on its surface.
- Mature T helper cell circulates in the blood circulatory system until it reaches an antigen representing cell (APC).
- If antigen-MHC complex on APC is complementary with the T cell receptor on the T helper cell, the T cell binds to the APC.
- T helper cell that binds with APC secretes interleukin 1.
- Interleukin 1 stimulates production of interleukin 2.
- Interleukin 2 stimulates the division of T helper cells and T cytotoxic cells to produce clones of effector T helper & effector T cytotoxic cells respectively and memory cells.
- Circulating T cytotoxic cells bind with complementary antigen-MHC complex on infected cells.
- Effector T cytotoxic cells release perforin that perforated the infected cells to stimulate autolysis.
- Effector cytotoxic T cells attacks other infected cells, as infected cell perform autolysis.
- Memory T cells respond for a second invasion of the same pathogen by actively dividing to form effector T cells.
Humoral Immune Response:
- B cells are formed and mature in bone marrow.
- Mature B cells synthesize antibodies, which attach to the 2 tips acting as receptors.
- B cells with complimentary antibody phagocytosise the free complimentary antigens encountered.
- Antigen is cut into smaller pieces and presented as the antigen-MHC complex on it's plasma membrane.
- T helper cell with complimentary T cell receptor binds to antigen-MHC complex.
- T helper cell secretes interleukin 2.
- Interleukin 2 stimulates B cell to divide and, form clones of effector B cells and memory cells.
- Effector B cells produce large quantity of free antibodies with same specific configuration.
- Antibodies destroys antigen by precipitation, antitoxins and agglutination.
Interesting how our immune system works, right?
The only problem is, it's only interesting when you need not memorize it for finals!