2. By

3. “ Immunity is basically a
biological term that describes a
state of having sufficient
biological defenses to avoid
infection, disease, or other
unwanted biological invasion ”

4.  There are 2 types of Immunity
1) Innate Immunity/Inborn Immunity
2) Acquired Immunity
The acquired Immunity is of two types.
1)Humoral/B-cell immunity: In this type of immunity
The body develops circulating Antibodies which are globulin
Molecules in the blood plasma.
2)Cell Mediated/T-cells Immunity: Its achieved through
Formation of large number of activated T-lymphocytes.

5. Cell Mediated immunity is initiated by
antigens,because
Acquired immunity does not develop until after
invasion by a foreign organism or toxin,its clear
that the body must have some mechanism for
recognizing this invasion.
Each organism or toxin almost always contain one or
more different specific chemical compounds in its
makeup.
In general these are protiens or large polysaccharides
And it is they that initiate acquired immunity/cell
mediated immunity.

6. Cell mediated immunity is the product of body”s
Lymphocytes which are located most extensively
In Lymph nodes,Spleen,Thymus,GIT and
Bone marrow.
T-lymphocytes forms activated lymphocytes
That provide CMI.

7. After originating in the bone marrow the
T-lymphocytes first migrate to the thymus gland.
Here rapidly divide and develop extreme diversity for
Reacting against different specific antigen.
One thymic lymphocyte develop specific reactivity
Against one antigen .then the next lymphocyte
Develops specificity against another antigen . This
Continues until thousand of different types of thymic
lymphocytes with specific reactivity against many
Thousand of different antigen which leaves the
Thymus and spread through blood.

8. T-lymphocytes specificity
Millions of different types of preformed T-lymphocyte
Have been stored in lymph tissues,each of these is
Capable of forming only one type of T-cells with
A single type of specificity and only the specific type
Of antigen with which it can react can activate it.
Once it is activated by its antigen it reproduce wildly.
Which are realesed into lymph and then carry to the
blood
and circulated.
All the different lymphocytes that are capable of
Forming one specific T-cell are called a
Clone of lymphocytes.

9. Formation of memory cells
When a clone of T-lymphocytes are
activated by an antigen,many of newly
formed lymphocytes are preserved in
the lymphoid tissues to become
additional T-lymphocytes of that
specific clone.these preseved cells or
memory cells are derived from normal
T-Cells that have learned how to
overcome an invader by remembering
the strategy used to defeat previous
infection.

10. T-lymphocytes respond to antigens only when they
Are bound to specific molecules called MHC protiens
On the surface of antigen presenting cells in the
Lymphoid tissue.The antigens on the surface of
Antigen presenting cells binds with receptor molecules
On the surface of T-cells and destroyed.
Three major types of antigen presenting cells are
1)Macrophages
2)B-lymphocytes
3)Dendritic cells
Dendritic cells are most potent antigen presenting
Cells located through out the body.

11. The MHC protiens bind peptide fragments
Of antigenic protiens that are degraded inside
Antigen presenting cells and then transport
Them to the cells surface.
Types of MHC protiens
1)MHC I protien which present antigens to cytotoxic
T-cells
2)MHC II potiens which presents antigens to T-Helper
Cells.
The antigens on the surface of antigen presenting cells
Bind with receptor molecules on the surface of t-cells
There are as many as one lac receptors site on single
T-cell.

12. Types of T-cells
1)Helper T-cells
2)Cytotoxic T-cells
3)Suppressor T-cells

13. Mechanism of CMI
1)Entry of the foreign particles
2)Antigen presenting cells
3)Role of MHC in Antigen presenting cells
4)Action of T-cells

15. Special thanks
to