1. INTRODUCTION TO THE IMMUNE SYSTEM

2. Innate and adaptive immunity

3. The course of a typical antibody response: The adaptive response takes 7-14 days to develop and mount a specific, protective immune response

4. An infection, and the response to it can be divided into stages and involves soluble mediators and cells of the immune system

5. Circulating lymphocytes encounter antigen in peripheral lymph nodes
The adaptive immune response develops
in the lymphoid tissues
Circulating lymphocytes encounter antigen in peripheral lymph nodes
Sentinel cells in the periphery
pick up pathogens and transport them
to the draining lymph node

6. The immune response is dynamic, involving cells re-circulating from the tissues via the lymphatics and blood system
Innate immunity acts locally in the infected tissue,
Adaptive immune responses develop in the lymphoid tissues,
Effector cells multiply and migrate back to tissue.

7. Cellular components of the immune system

8. Myeloid cells in innate and adaptive immunity

9. Phagocytic cells
Polymorphonuclear
neutrophils
Blood monocytes

10. Phagocytosis

11. The mononuclear phagocyte system

12. Mobilisation of defensive components of innate immunity

13. Macrophages and acute inflammation

14. B cells need T cell “help” to make antibody
Lymphocytes mediate adaptive (pathogen specific) immunity: each cell has a unique antigen receptor
B cells need T cell “help” to make antibody

15. Innate and adaptive (acquired) immunity are integrated

16. SUMMARY
The response to an initial infection occurs in three phases: innate, early induced, adaptive.

17. Cells of the innate immune system:, macrophages, granulocytes, natural killer cells, immature B cells
Release of soluble components to opsinise phagocytosis
Release of toxic granules to kill micro-organisms, parasites or virally infected cells
Release of soluble mediators to attract other leukocytes to site of inflammation
Removal of dead or dying cells
Transfer of infectious or toxic material to lymph nodes to initiate adaptive immune response

18. Cells of the adaptive immune system: Dendritic cells, T and B lymphocytes,
Lymphocytes are generated with unique antigen receptors on their surface.
Dendritic cells (and macrophages) present antigen to lymphocytes and provide activating signals
Lymphocytes undergo clonal expansion and migrate back to area of infection as effector cells.
T cytotoxic cells selectively kill virally infected cells
T helper cells selectively help B cells produce large amounts of high affinity specific antibody.
After infection, memory lymphocytes provide protective immunity

19. Natural killer cells kill virally infected cells
Virally induced
structures
IFN-g released by infected cell “primes”other cells to kill it