The immune system

Phagocytes ingest foreign materials eg microbes

Non cellular components of blood can transfer immunity (in the serum)

Cells in the bone marrow, thymus and lymphatic system, spleen and blood that function to protect us.

Anything causing an immune response.

Any disease causing micro organism.

Non reactivity of the immune system, usually refers to self but may include foreign tissue in organ transplants.

A failure of tolerance, the immune system reacts to itself.

Molecules released by pathogens and infected tissues to attract the cells of the immune system.

Signalling molecules released by a cell to cause a response in another cell.

Protection that is always present. Includes phagocytic macrophages and dendritic cells.

Protection that arises by an immune response, including humoral immunity producing antibodies and cellular immunity.

• -Present in vertebrates
• -non specific
• -immediate
• -cellular and humoral
• -no memory
• -receptors directly encoded in DNA

• -absent in invertebrates
• -specific (targets specific pathogen)
• -delayed response (5-7 days)
• -cellular and humoral
• -memory: response faster/improved on second exposure
• -receptors produced by DNA rearrangement in developing cells