1. Special Forces, Day II

2. B lymphocytes-humoral Immunity  Kill Ags indirectly through Abs  Less effective against viruses, transplanted tissues, & cancer  Abs (immunoglobulins) Found on B cell membrane Found on B cell membrane Secreted into blood Secreted into blood Quaternary globular protein, tetramer Quaternary globular protein, tetramer

3. Antibody Structure  Each polypeptide chain has 2 regions Variable region binds Ag (lock & key)-this makes up your individual “pool” of receptors (from genes) Variable region binds Ag (lock & key)-this makes up your individual “pool” of receptors (from genes) This region may vary from Ab to Ab, but is the same for a particular cloneThis region may vary from Ab to Ab, but is the same for a particular clone Constant region determines type (class) of Ab it is-all Abs of the same class have the same constant regions Constant region determines type (class) of Ab it is-all Abs of the same class have the same constant regions

4. Types of Abs  IgM-pentamer, 1 st made, activates complement, imp. Against viruses  IgG-most abundant circulating Ab,crosses placenta, triggers complement,main Ab in secondary immunity  IgA-found in mucus, saliva, tears, breast milk, can exit blood  IgD-who knows?  IgE-allergies, parasites

5. How Do Abs Kill Ags?

6. Classical Complement Pathway Requires activation by Ab-Ag complex Alternative complement pathway Non-specific May be triggered by membrane markers of bacteria, viruses, or protozoa No Ab-Ag complex necessary

7. http://www.cancerresearch.org/imm resp.html http://www.cancerresearch.org/imm resp.html

8. Secondary Immune Response (Immunological Memory) Secondary response-faster, more prolonged, greater magnitude Abs have greater affinity for Ag

9. Genetics of Immunity  MHC  Abs & T cell receptors 1 trillion receptors/Abs from 180 genes 1 trillion receptors/Abs from 180 genes DNA sequences are rearranged during development, PRIOR to Ag exposure DNA sequences are rearranged during development, PRIOR to Ag exposure Alternative RNA splicing also involved Alternative RNA splicing also involved Some evidence that Thelpers cause gene rearrangement which allows B cells to produce various Ab classes Some evidence that Thelpers cause gene rearrangement which allows B cells to produce various Ab classes

10. Diseases Related to Immune system  Cancer Tc & NKs patrol body-many cancer cells have mutated MHC markers Tc & NKs patrol body-many cancer cells have mutated MHC markers Some cancers have normal markers or attack NKs Some cancers have normal markers or attack NKs  Autoimmune disorders Failure to distinguish self from non-self Failure to distinguish self from non-self Arthritis-autoAbs form complexes around jointsArthritis-autoAbs form complexes around joints Diabetes-islet cells are attackedDiabetes-islet cells are attacked MS-schwann cells are attackedMS-schwann cells are attacked Lupus-attacks multiple systems in the body which may include- the skin, joints, blood, lungs, kidneys, heart, brain & nervous system.Lupus-attacks multiple systems in the body which may include- the skin, joints, blood, lungs, kidneys, heart, brain & nervous system. Allergies-Allergies- During 1 st exposure IgE binds to mast cells During 1 st exposure IgE binds to mast cells 2 nd exposure causes massive inflammation (histamine)- severe drop in blood pressure can lead to anaphylactic shock 2 nd exposure causes massive inflammation (histamine)- severe drop in blood pressure can lead to anaphylactic shock

11. Diseases cont…  Transplant rejections T cells attack due to foreign MHC markers T cells attack due to foreign MHC markers Immunosupressant drugs-usually against Th cells (cyclosporin) Immunosupressant drugs-usually against Th cells (cyclosporin)  AIDS Immunosuppressive retrovirus Immunosuppressive retrovirus Destroys Th & macrophages Destroys Th & macrophages Opportunistic, secondary infections result when immunity is sufficiently weakened Opportunistic, secondary infections result when immunity is sufficiently weakened  Stress Long term release of glucocorticosteroids from adrenal depresses inflammation, decreases # of phagocytes (inc. APCs), decreases interleukins Long term release of glucocorticosteroids from adrenal depresses inflammation, decreases # of phagocytes (inc. APCs), decreases interleukins  Aging T cells less responsive to Ag T cells less responsive to Ag

13. Let’s Review!!! WooHoo!!!