dpt physiolgy

1. Immunity

2. Immunity
• Ability to resist almost all kinds of organisms
or toxins that tend to damage the tissues and
organs.

3. Innate immunity
• Non-specific
• Activate immediately after antigen exposure
• Results from general processes like,
– Phagocytosis (by WBC and tissue macrophage system)
– Destruction of swallowed organisms (by acid sec. of
stomach and digestive enzymes)
– Resistance of skin to foreign organisms
– Chemicals in blood that destroy foreign organisms
• Lysozymesdissolve
• Polypeptidesinactivate gram + bacteria
• Complement complexdestroy bacteria
• Lymphocytesrecognise and destroy

4. Acquired ( adaptive) immunity
• Specific
• Body ability to develop powerful specific immunity against
individual invading agents like bacteria, toxins, virus and
foreign particles
• Activated only after antigen exposure
• Antigens i.e. protiens or large polysaccharides in foreign
particles initiate acquired immunity
• Forms antibodies and/or activated lymphocytes that attack
and destroy the invading organism
• Immunization (via vaccines) also develops acquired
immunity

5. Types of acquired immunity
1. Humoral immunity or B-cell immunity
2. Cell mediated immunity or T-cell immunity

6. Humoral immunity:
• Develops circulating antibodies in blood plasma that
attack invading agents
• B lymphocytes produce antibodies
Cell mediated immunity:
• Forms large number of activated T lymphocytes
specifically in lymph nodes and other lymphoid
tissues to destroy foreign agents

7. T and B lymphocytes
• T lymphocytes are preprocessed in Thymus
• T lymphocytes form activated T lymphocytes
• B lymphocytes are preprocessed in liver and bone
marrow
• B lymphocytes form antibodies
• Processing of B and T lymphocytes occurs in other
organs because stem cells are unable to form activated
T cells or antibodies directly.
• Helper T cellssecrete lymphokinesactivate b cells
to produce antibodies
• Memory cells

8. Processing of lymphocytes
• T cells are processed in thymus
• B cells are processed in liver and bone marrow
– B lymphocytelymphoblastplasmablastplasma
cells antibodies
– Some of the lymphoblast gets reconverted into B
lymphocyte to make memory cells
– Memory cells circulated and settled in lymphoid tissue
and remain dormant
– If exposure to same antigen 2nd timepatent and rapid
response.

9. • Antibodies produced by B lymphocytes have
antigen binding sites

11. • IgG
• IgA
• IgM
• IgE
• IgD

12. Passive immunity
• Directly infusing antibodies, activated T cells
or both obtained it from the blood of
someone else or from other animal. Such
transfusion of antibodies or T lymphocytes is
known as passive immunity

13. Thank you…