INNATE IMMUNITY: NEUTROPHILS AND THEIR PRODUCTS

Greek Greek MyelosMyelos = bone marrow = bone marrow

Bursa

Bone marrow

Act rapidily

Incapable of sustained effort

Act more slowly

NEUTROPHIL

8 x 106/min

Life span: 2-4 days

Cannot divide

Fine granular cytoplasm

Segmented nucleus

Two pools: circulatingand sequestered inmicrovasculature

Direct movement of cells (leucocytes) under the influence of an external chemical gradient.

CHEMOTAXIS

1

2

3

4

5

6

Bacteriaproducts

Integrins/selectins

(gradient)

Rolling Adherence Emigration

Selectin-mediated

Integrin-mediated

Inflammatorystimuli

Chemotaxis

Blood flow

The stages of neutrophil adhesion and emigration from blood vessels.

PMN

The proteins and their ligands engaged in neutrophil-vascular endothelial cell binding

Phagocytosis

-

+

C

+++

ADHERENCE AND OPSONIZATION

Opsonin (Greek > sauce). A molecule that facilitates phagocytosisby coating foreign particles (neutralizes –ve charges)

Zeta potential

Receptor for CReceptor for C

Receptor for AbReceptor for Ab

ADHERENCE AND OPSONIZATION

Streptococcus agalactie

NeutrophilNeutrophil

ADHERENCE AND OPSONIZATION

INGESTION AND PHAGOSOME FORMATION

PHAGOLYSOSOME

Neutrophil Activation

DESTRUCTIONThe Respiratory Burst

O2

1

3

4

5

Superoxide anion

Hydrogen peroxide

2

LYTIC ENZYMES

SURFACE RECEPTORS

The Removal of Apoptotic Neutrophils