Immunity to Infection Flashcards
What are the immune mechanisms used to defend against BOTH bacteria and viruses?
- Neutrophils and Macrophages
- Ab
- Ab with Complement
- Activated Macrophages
How do neutrophils and macrophages respond to bacteria/viruses?
Phagocytose and destroy intact organisms
How do Ab respond to bacteria/viruses?
Block the adsorption of the organism into the tissue by binding surface Ag
How do Ab with complement respond to bacteria/viruses?
Can bind host OR organism Ag to enhance neutrophil and macrophage phagocytosis or lyse the infected host cells
How do activated macrophages respond to bacteria/viruses?
Enhance the destruction of the engulfed organism
What immune mechanisms are used to combat only viruses?
- CD8 T cells
- NK cells
- Interferons
How do CD8 T cells respond to viruses?
Lyse cells that present viral proteins
How do NK cells respond to viruses?
Lyse viral infected cells
How do interferons respond to viruses?
Target non-infected cells and enhance their anti-viral capabilities
What immune mechanism are used to combat only bacteria?
-Ab for toxins
What are the mechanisms to attack extracellular bacteria?
Phagocytes and Ab are effective
What can be used against gram negative bacteria that are extracellular (Neisseria meningitidis)?
Complement System
What can be used against gram positive bacteria that are extracellular (Staphylococcus aureus)?
Opsonization
How are bacteria with anti-phagocytotic capsules dealt with (Streptococcus pneumoniae)?
Complement System
How are fungi (Candida albicans) dealt with?
Phagocytic cells
How are parasites dealt with?
Ab with complement and ADCC via eosinophils
Is innate immunity effective against parasites?
NO
How are intracellular bacteria/protozoa dealt with?
T cells with Th1
->Innate immune system is ineffective and Ab are INEFFECTIVE
How are viruses dealt with?
Usually all forms of immunity are used
What is the function of IFN-alpha?
It is made by leukocytes and targets virally infected cells to prevent viral replication
What is the function of IFN-beta?
It is made by fibroblasts and targets virally infected cells to prevent viral replication
What is the function of IFN-gamma?
Made by T cells and targets macrophages to activate them and up regulates MHC I and II
What are the two proteins that IFNs make?
Synthetase
Protein Kinase
What is the function of the IFN synthetase?
It catalyzes adenine polymerization and leads to ribonuclease cleavage of viral mRNA
What is the function of the IFN protein kinase?
It Pi EIF-2 an initiation factor that causes viral protein mRNA to remain untranslated and increases its cleavage
