1. Dr. Shaikh Mujeeb Ahmed Assistant Professor AlMaarefa College
IMMUNITY
HMIM BLOCK 224
Dr. Shaikh Mujeeb Ahmed
Assistant Professor
AlMaarefa College

2. Objectives General overview of the immune system
Different components of innate & acquired immunity.
Phases of immune response.

3. What is Immunity ?
Immunity is the body’s ability to resist or eliminate potentially harmful foreign materials or abnormal cells.

4. What are the types of immunity
Innate (natural) immunity
Acquired (adaptive) immunity

5. What is meant by innate immunity ?
Nonspecific responses
Inherent (innate or built-in) defense mechanisms
Nonselective defend against foreign or abnormal material of any type, even on initial exposure to it.

6. What is it includes? Barriers Defensive cells Chemical defenses
Physical
Chemical
Defensive cells
WBCs
Macrophages
Natural killer cells (NK)
Chemical defenses
Complement system

8. Barriers
Integumentary system
Mucus membrane & lysozyme

9. Cells Langerhans cells Phagocytes Natural killer cells
Basophils and mast cells

10. Chemicals
Interferon: (are named after their ability to "interfere" with viral replication)
Complement system: (helps or “complements” the ability of antibodies and phagocytic cells to clear pathogens from an organism)
Inflammation: (biological response of vascular tissues to harmful stimuli)

11. Interferon α, β, and γ interferon By infected cells
Function by blocking viral reproduction

12. Innate Immunity
Mechanism of Action of Interferon in Preventing Viral Replication

13. Complement System Series of ~ 20 proteins Activated by microorganisms
Will coat the microorganisms
Adherence reactions
phagocytic cells have receptors for C3
Biological active fragments
produce reactive oxygen intermediates
Membrane lesions
Activate mast cells
Inactivated---specific inhibitory proteins
if complement doesn’t bind quickly then ecome inactivated

15. Acquired (adaptive) immunity
specific immune responses selectively targeted against a particular foreign material to which the body has already been exposed.
The foreign material may be an antigen or a hapten (is a small molecule that can produce an immune response only when attached to a large carrier such as a protein)

16. Immune Response Antigen
Antigen – “any substance when introduced into the body stimulates the production of an antibody”
Bacteria, fungus, parasite
Viral particles
Other foreign material
Pathogen – an Antigen which causes disease

17. Immune Response Antibodies
Antibody – “a Y-shaped protein, found on the surface of B-Cells or free in the blood, that neutralize antigen by binding specifically to it”
Also known as an Immunoglobulin
Antigen

18. Hapten Not antigenic by itself
When combines with protein it become an antigen

19. Adaptive immunity Two types
Active immunity – direct encounter with the antigen.
Passive immunity – without encounter with the antigen
Antibodies transferred from mother to the fetus.
Immunization by injecting antibodies

20. Active immunity Cell mediated immunity (T cell immunity)
Antibody mediated (humoral/ B cell) immunity

21. T and B Lymphocytes

22. Origins of B and T lymphocytes
After early childhood most new lymphocytes are derived from peripheral lymphocyte colonies rather than from bone marrow

23. Interactions between T- and B-Cells
T- memory Cell
T-supressor
Pre-T
Cell
T-Cell
T8-ctotoxic
T4-helper
Bone Marrow
Pre-B
Cell
B-Cell
Plasma Cell
B- memory Cell
IgG
IgA
IgM
IgD
IgE

24. Phases of immune mechanism
Initial phase
Entry of antigen and its contact with the specific receptor on lymphocytic membrane.
Central phase
Cooperation among different subset of lymphocytes that proliferate and differentiate to form T & B lymphocyte + memory cells
Effector phase
Inactivation of antigen by sensitized T & B lymphocytes

25. References Human physiology by Lauralee Sherwood, seventh edition
Text book physiology by Guyton &Hall,11th edition
Text book of physiology by Linda .s contanzo, third edition