1. The Immune System
Dr. Jena Hamra

2. Immune System 3 major functions 2 types of immune responses
Protects body from disease
Bacteria, viruses, fungi, parasites
ANTIGEN: Anything that causes immune response
Remove dead or damaged tissue
Recognizes and removes abnormal cells
2 types of immune responses
Innate immunity
Nonspecific, immediate
Acquired immunity
Specific, can take several days

3. Anatomy of the Immune System
Lymphoid tissues
Primary
Bone marrow
Thymus gland
Secondary
Spleen
Lymph nodes
Diffuse tissues
Tonsils
GALT

5. Cells of the Immune System
Leukocytes
Eosinophils
Basophils/Mast cells
Neutrophils
Monocytes/Macrophages
Lymphocytes
Dendritic cells

6. Cell Function GRANULOCYTES Eosinophils Basophils Neutrophils
Fight parasites
Allergic reactions
Basophils
Release histamine, heparin
Neutrophils
Ingest and digest bacteria
Most abundant WBC in blood
Release pyrogens, mediators of inflammation

7. Cell Function Lymphocytes Monocytes Dendritic cells Secrete antibodies
Memory cells
Cytotoxic cells
Monocytes
Macrophages in tissue
Primary scavengers
Bacteria, tissue
Antigen presenting cells
Dendritic cells
Recognize, capture antigen

9. Innate Immunity Nonspecific response Physical barriers Phagocytes Skin
Mucous membranes
Ciliated epithelium
Phagocytes
Macrophages and neutrophils
Phagocytosis
Receptor mediated
Extravasation and diapedesis

11. Chemical Mediators Inflammation Acute phase proteins
Cytokines from macrophages
Chemotaxis
Increase capillary permeability
Fever
Acute phase proteins
Produced by liver
Released early in immune response
Opsonins, antiprotease

12. Chemical Mediators Histamine Interleukins
Located in granules of mast cells and basophils
Initiates inflammatory response
Increase capillary permeability
Edema
Vasodilation
Increased local blood flow
Interleukins
Interleukin-1
Secreted by activated macrophages
Stimulates acute phase protein synthesis
Induces fever
Stimulates cytokine release

13. Chemical Mediators Bradykinin Complement proteins Vasodilator
Stimulates pain receptors
Complement proteins
Cascade
Formation of membrane attack complex
Lipid soluble molecules
Insert into pathogen membrane, form pores
Cell lysis

15. Acquired Immunity Selective reaction to a specific antigen
Mediated by lymphocytes
Membrane receptors specific for particular ligand
Same specificity = clones
Clonal expansion
First exposure to antigen
Cells divide = new clones
Produces effector cells and memory cells
Second exposure to antigen
Activation of memory cells

17. Lymphocyte Cytokines
Required for activation and normal immune response
Interleukins
Clonal expansion and differentiation
Interferons
Alpha and beta: activate pathways against viral infection
Gamma: Activates macrophages

18. Lymphocyte Subtypes B lymphocytes T lymphocytes Secrete antibodies
Helper T cells (CD4): Secrete cytokines required for development of immune response
Cytotoxic T cells (CD8): Attack and destroy foreign cells
Natural killer cells: Attack and destroy virally infected or cancer cells

19. Antibody Secretion (Humoral Immunity
B cells
Activated B cells  Plasma cells
Plasma cells secrete antibodies
Primary and secondary antibody response
Primary: Slower and and weaker
IgM
Secondary: Faster, more antibodies produced
IgG

21. Antibodies IgG IgM IgA IgE IgD 75%, Secondary response
Primary antibody response
IgA
Secretory: saliva, tears
IgE
Allergic responses
IgD
Cell surface receptor on B lymphocytes

22. Antibody Structure Y shaped proteins 2 heavy chains, 2 light chains
Fab region: antigen binding sites

23. Antibody Function Opsonins Make antigens clump
Coat antigens, facilitate phagocytosis
Make antigens clump
Activate other immune cells
Cytotoxic T cells
Phagocytic cells
B lymphocytes
Activate complement
Activate mast cells

25. Cellular Immunity T lymphocytes T cell receptor
Mature in thymus
Require antigen presenting cells
Cytotoxic T cells
Helper T cells
T cell receptor
Required for recognition of antigen
Major histocompatibility complexes
Required for antigen presentation
CD4 recognize MHC II
CD8 recognize MHC I