lymphocytes

3 types of Lymphocytes according to

Their function t b nk

% of t life span receptors function 4 specific functions

60-80% years T cell receptors like cd4 and cd8 ptn cell mediated immunity Cytotoxic T cells Secrete perforins that from pores in cell

membrane of virally infected cells directly

killing them. 2-Helper CD4

T-cells

Activate B-cell

during humoral

immunit -Regulatory (Suppressor) T-cells

1-Maintain unresponsive to self-antigen.

2-Suppress XSS immune response 4-Memory

T-cells

Rapid response of

T-cells on re

exposure to the

same Ag. (2ry

immune respons

Maturation site

Stem cells in BM. • migrate to thymus gland, differentiate & acquire receptors (thymic-education)

B lymphocytes % receptors function specific function

20-30 receptors ig m d humoral immunity Functions : Humoral Immunity:

• When exposed to specific antigen, become activated by helper T-cell to :

1. Plasmablasts then plasma cells that produce antibodies.

2. Give B-memory cells: responsible for the rapid response on the 2nd exposure to the same Ag.

Human immunodeficiency virus (HIV):

destroys the T-helper cells → & immunity & the patient becomes

susceptible to infections

maturation site

Burse of fabricus in birds • Bone marrow in Mammals where they Develop receptors

Nk% receptors function maturation

5-10 cd16 neither t or b cell innate immune without stimulation of T cells similar of cytotoxic T cells but it secrets interferon develop of precursor of t and b cells doesn’t mature in thymus

Total leukocytic count

4-11k mm³

Counted by

Hemocytic meter or ec counting instrument

Abnormality

TT Total Numner. of WBCs

> 11,000/mm3.

1. physiological: (transient):

• during pregnancy, labor

• cold bath & exercise

2. Pathological:

due to infections either acute or chronic Number of WBCs <4,000/mm3. Causes:

• X-ray, irradiation

• Excessive use of antibiotics : e.g. chloramphenicol

Typhoid fever, Influenza virus

What is leukemia

Cancer that stats in the bone marrow

• very high leucocytic count.
  peripheral blood shows abnormal forms of WBCs with immature cells.

Leucocytic cell

The % of each type of WBCs to the total Number .

• Count in a blood film stained with leishma