Chapter 21.1 - 21.4 - Antimicrobial proteins and fever Flashcards
How do antimicrobial proteins enahnce innate defense?
Attacking microorganisms directly or hindering microorganisms ability to reproduce
What are the most important antimicrobial proteins?
Interferons and complement proteins
What is the function of interferons?
They warn healthy neighbouring cells by stimulating the production of proteins that block viral reproduction and degrade viral RNA.
What is the extra function of IFN type aplha and beta?
they also activate NK cells
What is the function of IFN gamma?
It has widespread immune mobilizing effects and activates macrophages
What are proteins of the complement system?
Proteins C1-C9, factors B, D, and P and regulatory proteins
hat does the complement system provide?
Maor mechanism for destroying foreign substances, activations enhances inflammation and also directly destroys bacteria
By which three pathways can the complement system be activated?
the classical pathway, lectin pathway and alternative pathway
What has every pathway in common?
Each pathway converges on C3 which cleaves into C3a and C3b
What initiates splitting C3?
Enhances inflammation, promotes phagocytosis and causes cell lysis
when does cell lysis begin?
C3b binds to target cell, triggering insertion of complement proteins called membrane attack complex into cell’s membrane
What is the function of MAC?
it forms and stabilizes a hole in membrane of microbe, causing influx of water an lysis of microbe
What also causes opsonization?
C3b
What happens with fever?
Leukocytes and macrophages exposed to foreign substances secrete pyrogens which acts on body’s thermostat in hypothalamus, raising body temperature
What are the benefits of fever?
It causes liver and spleen to sequester iron and zinc and increases metabolic rate which increases rate of repair
