1. The specific immune response
B and T lymphocytes

2. Immunity Non-specific system Specific system
Barriers
Cells
Cells
Phagocytes
Mast cells
Lymphocytes
Humoral
Cell mediated
Neutrophils
Macrophages
B Lymphocytes
T Lymphocytes
Helper
Killer
Suppressor
Plasma cell
Memory cell
Antibodies
Cytokines

3. THE SPECIFIC IMMUNE SYSTEM
This complex system has evolved to SPECIFICALLY identify and destroy foreign invaders. The system can remember an invasion and prepare itself for further attacks. The basis for this system is a group of highly specialised cells:
LYMPHOCYTES

4. LYMPHOCYTES Lymphocytes are produced in the bone marrow before birth.
They then mature and travel around the body.
They are NOT phagocytic.

5. Lymphocyte (huge nucleus, very little cytoplasm)

6. Immunity Non-specific system Specific system
Barriers
Cells
Cells
Phagocytes
Mast cells
Lymphocytes
Humoral
Cell mediated
Neutrophils
Macrophages
B Lymphocytes
T Lymphocytes
Helper
Killer
Suppressor
Plasma cell
Memory cell
Antibodies
Cytokines

7. The Specific Immune response
Humoral response
Cell Mediated response
B Cells
T Cells
These are 2 different types of lymphocytes that work in different ways and are matured in different areas of the body

8. B Lymphocytes and humoral immunity
B lymphocytes (B cells) involves antibodies which are present in body fluids or ‘humour’
Develop and mature in the bone marrow.
Takes place in the fetus
10 million different types
Specific
Divide by mitosis – clones

9. B CELL ACTIVATION B cell receptor binds to specific antigen Antigen
Plasma cells
divide and release antibodies to the antigen
Memory cell
remains in lymph nodes

10. Two types of cell develop:
Plasma cells
Secrete antibodies
Survive a few days
Make 2000 antibodies every second!
Responsible for immediate defence
Primary immune response
Memory cells
Live considerably longer than plasma cells (often decades!)
Don’t produce antibodies directly
On contact with antigen, rapidly divide and develop into plasma and memory cells.
secondary immune response
Immunological memory
(Greater intensity and more rapid)

11. Complete your diagram stages as we go through these.

14. How do B lymphocytes work?
Remember that each B cell has a specific B cell receptor on its surface.
This receptor recognises a specific antigen. There will be at least one B cell in your body for every antigen that you encounter.
When a B cell receptor binds with the correct antigen, the B cell divides by mitosis to form MEMORY CELLS and PLASMA CELLS
Plasma cells release millions of antibodies to the antigen. However, this is termed HUMORAL IMMUNITY since the antibodies cannot penetrate cells

15. Immunity Non-specific system Specific system
Barriers
Cells
Cells
Phagocytes
Mast cells
Lymphocytes
Humoral
Cell mediated
Neutrophils
Macrophages
B Lymphocytes
T Lymphocytes
Helper
Killer
Suppressor
Plasma cell
Memory cell
Antibodies
Cytokines

16. T lymphocytes and cell-mediated immunity
Respond to organisms own cells which have been invaded by non-self material, e.g. A virus or a cancer cell.
T lymphocytes develop and mature in the Thymus gland
HOW ?
Macrophage cells
Antigen-presenting cells

17. T lymphocytes
These cells are produced in the bone marrow and then move to the thymus, where they mature.
Each T cell has a specific receptor on its surface, the T cell receptor. This recognises a single SPECIFIC antigen.
In the thymus, T cells are exposed to the body’s antigens and are killed if they react.

18. Types of T lymphocytes:
T lymphocytes only respond to antigens that are attached to body cell: Cell-mediated immunity.
Types of T lymphocytes:
T helper cells
secrete chemicals= cytokines
T cytotoxic cells (T killer cells)
make holes in cell surface membrane using Perforins (proteins)
T suppressor cell
Turns off action of other lymphocytes once pathogen has been eliminated from body.

19. Complete your stages for cell-mediated immunity

20. Copy and complete the following table into your notes:
Lymphocyte type
Site of development and maturation
Role in immunity
B lymphocyte
Plasma cell
Memory cell
T lymphocyte
T Helper cell
T Cytotoxic cell
T Suppressor cell

21. Tasks: Try the following question on B lymphocytes: Jan 2001

24. Testing understanding......
Tell the person you are sat next to how B lymphocytes form part of the immune response,
Swap
The partner now needs to tell you how T lymphocytes form part of the immune response.

25. June 2004 – T Lymphocytes Q answers
bone marrow; R marrow on own
phagocytes / neutrophils / PMNs / monocytes / macrophages;
thymus;
plasma cells / effector cells;
antibodies; 5

26. ref to antigen presentation / described;
receptors on T cell (surface) are complementary to antigen; R same shape
ref to specificity (in context of T cells);
clonal selection / described;
clonal expansion / clonal proliferation / T cells divide by mitosis;
R ‘T cells clone’ unqualified / ‘reproduction’ / ‘replication’
T helper cells release, cytokines / lymphokines;
stimulate B cells to, divide / clone / differentiate (into plasma cells);
stimulate macrophages to carry out phagocytosis (more actively);
Tc / cytotoxic / killer (T) cells, search for / kill / attach to, infected (host) cells;
secrete, enzymes / toxins;
named enzyme / toxin;
e.g. hydrolytic / protease / nuclease / H2O2 / free radicals / perforin
active immunity;
memory (T) cells / immunological memory;
ref to secondary response; e.g. more rapid / greater
AVP; e.g. suppressor cells
AVP; e.g. function of suppressor cells
cell mediated response
max 7
QWC – clear, well organised using specialist terms; 1