immunity with cells and organs of the immune system. an insight on the mechanism of antigen presentation to the immune system and a little introduction to organ transplant.google and slideshare helped a lot in making this presentation

1. IMMUNITY
Dr. DUR-E-ZAHRA
MPHIL HAEMATOLOGY SCHOLAR

2. LEARNING OBJECTIVES
• Normal immune response
• Cells and tissues of immune system
• Overview lymphocyte activation and adaptive immune
response
• Human leucocyte antigen system

3. Definition
The capability of human body to resist almost all types of
organisms or toxins that tend to damage the tissues and organs
is called immunity

4. Types of immunity
Innate immunity Acquired Immunity

6. Innate Immunity
• Inborn immunity
• Naturally present
• Non specific
• without prior sensitization to a specific antigen

8. ACQUIRED IMMUNITY
• The immunity which is formed in response to invasion by any foreign
ANTIGEN
• Cell mediated and Humoral(antibody mediated) immunity
• It is the acquired or adaptive immunity which we call as a NORMAL
IMMUNE RESPONSE

9. Basis of normal immune response
• Antigen enters the body
• The immune system recognizes it as non-self
• Prepares to destroy it before it destroys the body

10. Cells of innate immunity
• Macrophages
• Neutrophils
• Natural Killer cells
• Dendritic cells (link b/w innate and adaptive immunity)
inflammation

11. CELLS OF ACQUIRED IMMUNITY
• Key role players are LYMPHOCYTES
• B-Lymphocyte (Humoral immunity)
• T-Lymphocyte (Cell mediated immunity) CD8+, CD4+

12. HUMORAL IMMUNITY
• Is brought about by antibodies produced by B cells
• Structure is made of heavy and light chains
• Function is brought by
a) direct attack on invader
b) activation of complement system

13. Cell Mediated Immunity
(cytotoxic T-cells)
• Matured in thymus
• Important defense against intracellular pathogens and tumor surveillance
• Interact with MHC I proteins
 secretion of cytokines
 production of cytotoxic granules
 destruction of infected cells by Fas/FasL interactions

14. Cell Mediated Immunity
(Helper T cells)
• Also called CD4 +
• Interact with MHC II proteins
• Th-1 or Th-2 on the basis of production of different
cytokines against intracellular and large extracellular
organisms respectively

15. Tissues of the immune system
• The cells of acquired immunity i.e Lymphocytes are present
in lymph nodes but also in the
• Lymphoid tissues i.e spleen,GIT ,thymus and bone marrow

16. T cell Activation
• It is the process by which a specific clone of the T-
cells becomes activated to differentiate and
proliferate against a specific antigen after coming in
contact with an ANTIGEN PRESENTING
CELL in the lymphoid tissue.

17. ANTIGEN PRESENTING CELLS
• Antigen-presenting cells (APCs) are the immune cells that
mediate the cellular immune response by processing and
presenting antigens for recognition by lymphocytes.
• Classical APCs include dendritic cells, macrophages,
Langerhans cells and B cells

19. Major Histocompatibility Complex (MHC)
• MHC is a group of genes which expresses proteins on
the surface of all nucleated cells and platelets
• It plays a role in antigen presentation to T-Lymphocyte

20. Types of MHC
•MHC I Cytotoxic T cells
(located on all nucleated cells and platelets)
•MHC II Helper T cells
(located on antigen presenting cells)

23. Naïve T-cell in Lymph node

32. Major Histocompatibility Complex (MHC)
• “Histo” means “tissue”
• “compatibility” means “getting along” or “agreeable”
• Discovery occurred during Transplantation Experiments
on mice

33. Human Leukocyte Antigen (HLA) System
• The major histocompatibility complex (MHC) in humans is
known as Human Leukocyte Antigen (HLA) and is present on
short arm of chromosome 6
• The MHC is divided into three categories
1.class I
2.class II
3.class III

35. Structure of MHC proteins

36. Role Of HLA Complex
• Organ transplantation
• Regulation of immune system
• Association of diseases with HLA

37. •Thank you very much for your
presence and time.
•Qs?