phagocytosis

1. phagocytosis
Dr.T.Arivazhagan
Department of pathology

3. •It is a process in which leucocyte and macrophages
release some enzymes for elimination of microbes

4. Leucocyte activation?

5. Recognition of the microbes or dead cells which
induces several responses in leucocytes that are
collectively called as leucocyte activation
1. Membrane remodeling
2. Cytoskeletal changes

7. steps
Recognition Attachment Engulfment Killing

8. Phagocytic receptors
1. Scavengers receptors
2. Mannose binding receptors
3. Opsonins – IgG antibodies, C3b , Lectins

10. Engulfment
1. Formation of pseudopods
2. Extension of the cytoplasm
3. Flow around the microbes
4. Phagosome – vesicle formed by plasma membrane

12. killing
Accomplished by
1. Reactive o2 species
2. Reactive nitrogen species
3. Lysosomal enzymes

13. Reactive oxygen species
Rapid
activation
of NADPH
oxidase

16. Antioxidant
1. Superoxide dismutase
2. Catalase
3. Glutathione peroxidase
4. Ceruloplasmin
5. Transferrin
Serum
Tissue fluids

17. Nitric acid
• Produced from arginine
• By nitric acid synthase enzyme
1. eNOS
2. nNOS
3. iNOS

18. Like ROS ,it attack & damage the lipids, proteins,
nucleic acids of the microbes

19. Lysosomal enzymes
1. Specific or secondary granules or smaller
• Lysozyme,collagenase,gelatinase
2. Azurophilic or primary or larger
• MPO,acid hydrolase
Released
from
Neutrophils

20. Anti-protease
1. Alpha 1 antitrypsin
2. Alpha 2 macroglobulin