Lecture 10 Innate host resistance Flashcards
Lack of resistance to a disease
susceptibility
Ability to ward off disease
Immunity
Recognizes foreign substances or microbes and acts to neutralize or destroy them
Immune system
Defense agains any pathogen
innate immunity
Immunity or resistance to a specific pathogen
Adaptive immunity
Anitmicrobial secretions in mucus membranes
- Lysozyme
- hydrolyzes bond connecting sugars in peptidoglycan
- Lactoferrin
- secreted by activated macrophages and PMNs
- sequesters iron from plasma
- Lactoperoxidase
- Produces superoxide radicals
Paneth cells produce ___ and ___
- lysozyme
- cryptins
What is in tears
- Lysozyme
- Lactoferrin
- secretory IgA
function of Antimicrobial peptides (AMPs)
Inhibit cell wall synthesis, form pores in the plasma membrane that cause lysis; and destroy DNA and RNA
First class of cationic peptides
- linear, alpha-helical peptides that lack cysteine amino acid residues
- e.g. cathelicidin
second class of cationic peptides
- defensins, peptides that are open-ended, rich in arginine and cysteine, and disulfide linked
- alpha and beta
Third class of cationic peptides
- Larger peptides that are enriched for specific amino acids and exhibit regular structural repeats
- e.g. histatin
The complement system is composed of greater than ___ serum proteins
30
what are the three major activities of complement system
- defending against bacterial infections
- bridging innate and adaptive immunity
- disposing of wastes
what are the three major activation pathways fo the complement system
- Alternative
- Lectin
- Classical
Which complement pathway is involved in nonspecific defenses against intravascular invasion by bacteria/fungi
Alternative Complement Pathway
The alternative complement pathway begins with the activation of
C3
The alternative complement pathway is dependent on
interaction of complement with repetitive structures on pathogens
The Alternative complement pathway results in formation of
Membrane attack complex
The classical complement pathway is usually dependent on
antigen-antibody interactions (thus it is part of acquired iimmunity and not as fast as other pathways)
The lectin complement pathway begins with
activation of C3 and lectin binding
The lectin complement pathway is dependent on
- interaction of host mannose binding protein (MBP) with pathogen surfaces
- enhances phagocytosis
