ADAPTIVE IMMUNE SYSTEM

2. Adaptive immune system
• Four characteristics
_diversity-in recognizing structure of antigens
– Antigenic Specificity – ability to recognize and respond to
particular targets.
– Memory – second exposure to the same organism
produces a larger and more rapid response than occurred
at the primary exposure.
– Self/non self recognition

3. TYPES OF IMMUNITY

5. ACTIVE IMMUNITY
• EXPOSURE TO ANTIGEN
• IMMUNITY ACHIEVED BY
INJECTING ANTIGENS
• ACTIVATION OF IMMUNE
SYSTEM
• IMMUNE STATE DEVELOPS
OVER A PERIOD OF WEEKS
• IMMUNOLOGICAL MEMORY
DEVELOPS
PASSIVE IMMUNITY
• NO EXPOSURE TO ANTIGEN
• IMMUNITY ACHIEVED BY
INJECTING Ab or Ag REACTIVE
T CELLS
• NO IMMUNE SYSTEM
ACTIVATION
• IMMUNITY DEVELOPS
IMMEDIATELY
• NO IMMUNOLOGICAL
MEMORY DEVELOPS

7. cells
T -
lymphocytes
Effector T cells
Activated T
helper cells
Cytotoxic T
lymphocytes
Memory T
cells
B lymphocytes
Memory B
cells
Plasma cells
Antigen
presenting
cells

8. a) B lymphocytes
• Mature within bone marrow
• B cells receptor is a membrane bound
antibody molecules.
• Can recognize antigen alone
• Two types-
 Memory B cell- longer life span
-same membrane bound antibody as
their parent B cells
 Plasma cells-secretes antibodies

9. b) Antigen presenting cells
• They express class ll
MHC molecule on their
membrane.
• They are to deliver a
single that is necessary
for T helper cell
activation

11. c) T lymphocytes
• Formation and maturation
• Recognizes only antigen bound to cell
membrane proteins called major
histocompatibility complex (MHC)
• Two type of MHC molecule-
Class l MHC-expressed by all
nucleated cells of vertebrates species
Class ll MHC- expressed by only
antigen presenting cells

12. Helper T lymphocyte
• Have CD4 glycoproteins on their surface.
• Interact with MHC class ll molecules
• Secretes many growth factors,
cytokines, interleukin
• Activate s macrophages, B cells, Tc cells
and other cell

13. Activation of T cells: Helper
Activated helper T cell
Monokines
MHC Class II
T cell receptor
Antigen-presenting cell
CD4 protein
Antigenic peptide
Antigen is
processed
Resting helper T cell
Class II MHC
Lymphokines
Helper T cell receptor
recognizes processed
antigen plus Class II
MHC
Macrophage
Processed antigen
and Class II MHC
are displayedAntigen
Helper T cell

14. T cytotoxic cells
• Also known as killer T cells. Have CD8 glycoprotein
• Stimulated by cytokines released by T helper cells
• Recognizes antigen MHC class l molecules complex
• Differentiates into cytotoxic T lymphocytes
• No cytokine secretion
• Exhibits cell killing activity for altered self cells-tumor cells &
virus infected cells

16. Antigen receptors
Killer cell
Infected cellAntigen-presenting cell Antigen-presenting cell
CD8
protein
Cell
membrane MHC
Class I
MHC
Class I
Antigenic
peptide
T cell
receptor
CD4
protein
Cell
membrane MHC
Class II
Antigenic
peptide
T cell
receptor
Cell
membrane
Antigen
Antigen-
specific
receptor
Helper T cellB cell

17. Types of immune response
Acquired
immune
response
Cell mediated
response
T lymphocytes
Humoral
response
B lymphocytes

20. THANK YOU