CELLS OF THE IMMUNE SYSTEM

Differentiation of Stem cells into B cells and T cells

Bursa of Fabricius

CELLS OF THE IMMUNE SYSTEM

Cells of the Immune System

Immune System

Myeloid Cells Lymphoid Cells

Granulocytic Monocytic T cells B cells

NeutrophilsBasophils

Eosinophils

MacrophagesKupffer cells

Dendritic cells

Helper cellsSuppressor cellsCytotoxic cells

Plasma cells

NK cells

Characteristics of B cells, T cells and Macrophages

CD4 (TH ) : MASTER REGULATOR• INFLUENCE functions of all cells of

immune system FUNCTIONALY TH1 TH2• IL 2, IF gamma IL4, 5,6,1O• Cytotoxic, Inflamm B cell

proliferation• Intracellular pathogens Ab production

viruses extracellular pathog

• Cell mediated imm Humoral immunity• Facilitate type lV hypersensitivity

MACROPHAGES

•HUMORAL IMMUNITY

B CELL PROLIFERATION

MARKERS: B LYMPHOCYTES

• B- LYMPHOCYTES• MATURE : Ig on surface– IgM, IgD Fc portion of IgG, C3, EB virus• IMMATURE CELLS Pre-B cells– u chains in

cytoplasm

CLONAL SELECTION The four basic principles of the clonal selection hypothesis

Each lymphocyte bears a single type of receptor of a unique specificity

Interaction between a foreign molecule and a lymphocyte receptor capable of binding that molecule with high affinity leads to lymphocyte activation

The differentiated effector cells derived from an activated lymphocyte will bear receptors of an identical specificity to those of the parental cell from which

that lymphocyte was derived

Lymphocytes bearing receptors specific for self molecules are deleted at an early stage in lymphoid cell development and are therefore absent from the repertoire of

mature lymphocytes

CLONAL SELECTION

UNIQUE SPECIFICITY

LYMPHOCYTE

ACTIVATION

DIFFERENTIATED

EFFECTOR CELL

Summary of Humoral Immunity

HUMORAL IMMUNE RESPONSE (Cooperation of cells)

B-CELL AS ANTIGEN PROCESSING CELL

•CELL MEDIATED IMMUNITY

MARKERS:T LYMPHOCYTES

• T- LYMPHOCYTES: MATURE CELLS• Surface antigens detected by Specific

monoclonal antibodies--- CLUSTER DIFFERENCIATION : CD T- helper cells: TH– CD4+

T- delayed type :TD – CD4- T- suppressor cells: TS– CD8-

T – cytotoxic type: TC– CD8+ MHC CLASS 1= CD8 MHC CLASS II=CD4• T - IMMATURE CELLS Prothrombocytes – Tdt – terminal

deoxynucleotidyl Immature thrombocytes -- Tdt

transferase

• CD4 (TH ) : MASTER REGULATOR • INFLUENCE functions of all cells of immune

system FUNCTIONALLY TH1

IL 2, IF gamma

Cytotoxic, Inflammatory

Intracellular pathogens

Cell mediated immunity Facilitate

type lV hypersensitivity

Macrophages activation

Synthesis of IgG2 Antibodies

TH2

IL4, 5, 6,10

B cell proliferation

Extracellular pathogensHumoral immunitySynthesis of other IgIncluding IgE.

T- CELL RECEPTOR (TCR)

CMI -- CLONAL EXPANSION

Cell Mediated Immunity

Summary of cell mediated immunity

ACTIVATION OF HELPER T CELL

ACTIVATION OF CYTOTOXIC T CELL

CYTOTOXIC T CELLS

COMPARISON OF HUMORAL :CELL MEDIATED IMMUNE

RESPONSE

THANKS

CLONAL PROLIFERATION OF T CELLS