innate immunity Flashcards
phagocytic cells
ability to eat and destroy
* myeloid (neutrophils, eosinophils, basophils)
* macrophage- monocyte
neutrophils
granulocytes, phagocytic
* rapid phagocytosis but cannot phagocytose repeatedly
* have granules which contain bactericidal enzymes
* short lived
* no ability to present antigens
Macrophages and monocytes
granulocytes, phagocytic
* slow but can phagycytose repeatedly
* contain bactericidal enzymes
* long lived
* selected cells have abilty to present antigens
lysozymes
bactericidal
myeloperoxidase
bactericidal
superoxidase dismutase
bactericidal
lactoferrin
Binds iron, therefore, iron is not
available for bacterial growth.
collagenase
Dissolves collagen when entering
tissues that have invading antigen
defensins
Inserts between lipid bilayers and disrupt the interactions of lipid molecules
neutrophilia
increase in number of neutrophils
indicative of infection
neutropenia
decrease in number of neutrophils
can be killed by pathogen
killing methods by neutrophils
- phagocytosis
- respiratory burst
- extracellular traps (NETs)
phagocytosis steps
- Chemotaxis
- Attachment
- Phagocytosis
- Destruction
chemotaxis (of phagocytosis)
- chemical messages released from site of injury/inflammation attract phagocyte to the site of pathogen/tissue destruction
- Adherence to vascular endothelial cells: Increased expression of adhesion molecules on the surface of endothelial cells favoring attachment to surface molecules on neutrophils
- increase in spaces between cells of endothelium
-
Diapedesis- Neutrophils migrate out of blood
vessel and enter injured site.
attachment (of phagocytosis)
neutrophils and antigen attach to trigger ingestion
1. Zeta Potential (both cell surface of phagocytes and antigens are negatively charged, therefore repel. The zeta potential needs to be reduced.)
2. Opsonins (are proteins that bind to antigen to facilitate phagocytosis and decrease zeta potential. The process is called OPSONIZATION. Eg. Complement components; antibody; a-fetoproteins)