Week 3 - Adaptive Immunity

Capacity of the immune system to successfully defend the body against a potentially infectious agent

Lymphocytes

• B cells - T cells

Stem cells in bone marrow

Any substance that the body recognises as foreign, or non-self

• Anti-body mediated immunity - Cell-meditated immunity

• This response activates B-cells that then proliferate and produce: - Plasma cells - Memory cells • Involves the activation of B cells and secretion of antibodies when in contact with a pathogen. • Produces antibodies to destroy microbes

• Destroys infected cells - Immune response that does not involve antibodies.

• B cells • Plasma • Memory

• T cells - Memory-T cells

Fight bacteria and viruses by making Y-shaped proteins called antibodies, which are specific to each pathogen and are able to lock onto the surface of an invading cell and mark it for destruction by other immune cells

Produce antibodies which circulate in the blood and other body fluids which target bacteria and their toxins and prepare them for destruction, also target viruses before they enter body cells

Persist in the body for months - years and can react with the same antigen again if it enters the body at a later date

Destroy cells that harbour viruses or bacteria and cancer cells and parasites. They fight intracellular pathogens

Specifically produced to the microbe

In the bone marrow

In infected cells

Response of the immune system the first time it is exposed to a particular antigen. There is a lag period 5 – 7 days in which there’s no increase in the level of antibodies in the blood.

Due to increased numbers of specific memory cells which are more easily stimulated to produce plasma cells which produce antibodies. The memory cells provide immunological memory.

Causes the many memory cells to rapidly produce new plasma cells & large numbers of antibodies within a few days. Possessing memory cells & the capacity to produce a rapid secondary response means that a person is immune to that specific antigen.

• igG • igA • igM • igE

• Protect against bacteria, neutralise toxins and viruses, trigger complement, make phagocytosis more effective. • The longest-lasting of the antibodies in the blood • Can cross the placenta so foetus and new-born get some protection from mother.

• Most common antibody in secretions and on mucus membranes • Bind antigens before they invade tissues and prevent microbes adhering to mucus membranes - especially in respiratory system • Most abundant antibody in the body

• Breast milk • Saliva • Tears