1. kidney

3. IMMUNITY
Dr Farzana Salman

4. Immunity
The ability of the body to resist all types of organisms or toxins that tend to damage the tissues and organs is called immunity.
Innate immunity
Acquired immunity

5. INNATE IMUNITY Prior to exposure to pathogen. Non specific
Does not improve after exposure to antigen
No memory

6. Innate Immunity
Phagocytosis of bacteria and other invaders by WBC and cells of tissue macrophage system.
Destruction of swallowed organisms by acid secretions of stomach and digestive enzymes.
Resistance of skin to invasion by organisms .
Chemical compounds present in blood
Lysozyme
Basic polypeptides
Complement complex.

7. Acquired Immunity Specific immunity Develops after exposure to antigen
Improves on repeated exposure
Memory cells are formed

8. Acquired Immunity Humoral / B- cell immunity
B lymphocytes
Antibodies
Cell mediated immunity / T cell immunity
T lymphocytes
Activated T lymphocyte

9. Antigens Molecules that react with antibodies . Nonself
Molecular weight = or greater
Epitopes – regularly recurring molecular groups on the surface of large molecules.

10. Preprocessing of T/B Lymphocytes
Pluripotent hematopoietic stem cell
Lymphoid progenitor cells
Thymus ---- T lymphocytes
Liver and bone marrow---- B lymphocytes

11. Clones of Lymphoytes
All different lymphocytes that are capable of forming one specific antibody or T cell are called clones of lymphocytes.

12. Mechanism for activating a clone of lymphocytes.
Role of macrophages in the activation process.
Antibodies formation
Memory cells

14. ANTIBODIES Immunoglobulins Molecular weight = 160,000- 970,000
20% of plasma proteins
Heavy and light chains

18. Affinity Constant
Ka = Concentration of bound antibody –antigen / Concentration of antibody x Concentration of antigen.

20. Classes of Antibodies
IgM
IgG
IgA
IgD
IgE

21. IgG – bivalent
75% antibodies in a normal person
Predominant in secondary response
Cross the placenta
Activate compliment system
Proinflammatory and antiinflamatory

22. IgE --- Involved in Allergy
Serum IgE levels are increased in parasitic infestations
IgM—10 binding sites
Main antibody formed during primary response.
Activate compliment system

23. IgA--- Main antibody in secretions such as colostrum,saliva,tears,respiratory ,intestinal and genital secretions.
IgD– No known antibody function
Act as antigen receptor . Present on surface of many B lymphocytes.

24. Mechanism of Action of Antibodies
Direct attack on invader
Activation of Complement system.

25. Direct Action of Antibodies
Agglutination
Precipitation
Neutralization
Lysis

26. Agglutination

27. Complement system For Antibody Action
20 proteins (enzyme precursors)
Principal actors in this system are 11 proteins
C1 to C9
B and D

28. Classic pathway
Alternative pathway

29. Classical Pathway of compliment system

30. C3b---Opsonization and phagocytosis
C5b Lytic complex
Agglutination
Neutralization of viruses
C5a---- Chemotaxis
C3a,C4a,C5a---- Activation of mast cells and basophils
Inflammatory effects

31. Alternate Pathway
Polysaccharides of invading organisms combine with Factor B and D.
This complex activates C3 to C3a and C3b
Onwards reactions are same as in classic pathway