A presentation about the various Functions of T Lymphocytes, and the Clinical problems that arise when their balance is disturbed.

2. Presented by:
1. Memoona Zamurad (102)
2. Maryam Ikram (108)
3. Mavra Hafeez (114)
4. Mommal Rasool (120)
5. Noreen Riaz (126)

3.  Main defense systems of body
 Skin
 Glands and their secretions
 White blood cells : Lymphocytes
B
Lymphocytes
T
Lymphocytes
Anti body
production
Self activation

4.  Originate in Bone marrow
 Pluripotent hematopoetic stem cells
common lymphoid progenitor cells
 Proliferation and education in THYMUS
gland.
 Reaction against self-antigens ;90-95% cells
destroyed.
 Specificity

6.  CD 4-helper T Cells
 CD 8-cytotoxic T cells
 Suppressor T Cells
 Memory cells

7.  Helper T cells; CD4
 3/4 of T cells.
 Types : TH1 and TH2
 Major regulators : LYMPHOKINES PRODUCTION
(That act on other cells as well as on bone
marrow) Include;
Interlukin-2,3,4,5,6 , granulocyte-
monocyte colony stimulating factor,
interferon-&.
AIDS; destruction of helper T cells

8.  Stimulation of cytotoxic and suppressor T
cells.
 Stimulation of B-cell growth and
differentiation to form plasma cell clones
 Activation of Macrophage system
 Feedback stimulatory effect on helper T cells
themselves.

10.  Killer cells ; CD8
 Direct attack on micro-organisms
 PERFORINS : hole-forming proteins
 Release of cytotoxic substances into the
attacked cells
 Cell swell and thus destroy.
 Lethal to TISSUE CELLS invaded by VIRUSES.
 Important role in destroying CANCER CELLS,
HEART TRANSPLANT CELLS, or other cells
foreign to body.

13.  Less known cells
 Suppress function of cytotoxic and helper T
cells.
 Prevent damage to body itself
 REGULATORY CELLS along with helper cells
 IMMUNE TOLERANCE:

15.  These are activated by antigens but do not
enter in circulation
 Remain in lymphoid organs
 Migrate to various lymphoid tissues
throughout the body
 If attacked by same antigen again,
immediate response.
 More POWERFUL response

17. Autoimmune disorders
Immune deficiency diseases
Allergic reaction
Tissue rejection

18.  IMMUNE TOLERANCE; unresponsiveness of
immune system to any substance capable to
elicit immune response.
 Developed in THYMUS ( self-antigen reaction)
 BUT IF IT FAILS…….
 AUTO-IMMUNITY: 2 types
Organ specific Organ non-specific
BYSANDER EFFECT; inflammation sensitizes
neighboring T cells which would not respond
normally

19.  “Defective immune system” pathogens
attack easily
 OPPURTUNISTS; organisms taking advantage
of defective defense mechanism.
 2 TYPES:
 CONGENITAL immunodeficiency diseases
(inherited defect in immune system)
 ACQUIRED immunodeficiency diseases
( infection by some pathogen)

20.  DIGEORGE’S SYNDOME; absence of thymus
gland genetically
 SCID-Bubble boy disease; lack of ADA
enzyme due to defect at chromosome 22,
lymphoid tissue absent

22.  AIDS
 LYMPHOMA
 Lymphoma: “solid tumor of
lymphoid cells”
 may develop in bone marrow , spleen,
lymph nodes, blood or any other organ.
 Fast and abnormal division of lymphocytes .

24.  Cause; HIV
 Cd4 COUNT ; Less than 200 cells/mm3
while normal is 500-1500cells/mm3.
 MODE OF ACTION:
 Glycoprotein from HIV binds to specific
receptor on cd4 cells.
 release of HIV RNA into host cell
 action of REVERSE TRANSCRIPTASE
 viral RNA viral DNA
 new HIV form, host cell burst and virus
enter in bloodstream, infecting more cells,

27.  INCUBATION PERIOD: No symptoms for several
weeks after exposure
 Symptoms develop when sufficient number of
cells ruptured
 COMMON symptoms are ;
fatigue chronic diarrhea
loss of appetite night sweat
low-grade fever oral ulcers
vaginal ulcers etc

29. Which mostly kill the AIDS patient are
 Pneumocystis pneumonia
 Kaposi sarcoma ( malignant skin cancer)
 Respiratory tract infections
 Lymphomas
Mode OF TRANSMISSION:
Exposure to secretions from infected person i.e
through blood transfusion,from mother to fetus
and by vaginal sexual intercourse
PREVENTION;
Awareness among people
Blood screening

30.  15OO-4000cells/ul of blood.
 20;40% of total WBCs
 LYMPHOCYTOSIS: “Increased lymphocytes”
1) ABSOLUTE L.C increased i.e. total
lymphocytes greater than 4000.
2 )RELATIVE L.C increased i.e. increased
proportion of lymphocytes than 40% but
Absolute count IS NORMAL
 LYMPHOCYTOPENIA: “ Decreased
lymphocytes than 1000cells/ul.”

31.  Is caused by activated T cells.
 An inflammatory reaction
 Secondary response appearing after 48-72
hours of exposure.
 Poison ivy rash: serious tissue damage of skin
on repeated exposures.
 Lungs edema
 Aesthematic attacks

32.  T cells cause tissue rejection of any foreign
tissue or organ transplanted.
PREVENTION
=> by killing T cells by Azathioprine.
=> inhibit cytotoxic T cells proliferation by
Glucocorticoids ( Cushing syndrome ).
=> immunosuppressive drugs such as
Cyclosporine.