Cells of the Immune System Flashcards
What are the two soluble factors of innate immunity?
Antibacterial factors
Complement system
What is a cellular factor of innate immunity?
Scavenger phagocytes
What are two types of antibacterial factors?
Lysozymes
Lactoferrin
How to lysozymes work as part of innate immunity?
Present at mucosal surfaces
Active in breaking down the gram positive cell wall of bacteria
How does lactoferrin work as part of innate immunity?
Present at mucosal surfaces
Binds free iron and therefore reduces soluble iron in the GI/respiratory tract to inhibit bacterial growth
What are the three final pathways of the complement system?
Opsonisation of pathogens
Recruitment of inflammatory cells
Killing of pathogens
What are the two functions of macrophages in immunity?
Clearance of microorganisms
Recruitment of help from other cells e.g. lymphocytes
What are macrophages (tissue) derived from?
Monocytes (blood)
What are the three main roles of macrophages?
Phagocytosis
Antigen presentation - presents to T cells in MHC II
Cytokine production
What is the role of pattern recognition receptors?
Recognises extracellular and intracellular threats to produce a response
Responds to bacteria, yeasts and fungi by releasing interleukin-1beta and TNF-a
Why may innate immunity not always be enough? (2)
- Highly pathogenic bacteria which can evade immune response
- Structural failure - e.g. wounds
What percentage of white blood cells is composed of neutrophils?
50-70%
What are the main roles of neutrophils? (4)
Chemotaxis
Phagocytosis - uses proteases, ROS, lysozymes etc
Degranulation - toxic
Die locally - produces pus
What percentage of white blood cells is composed of eosinophils?
1-6%
What to eosinophils usually respond to in immunity?
Parasites
What pathological mechanism can be caused by eosinophils?
Allergy
What are the main roles of eosinophils? (3)
Chemotaxis - in response to chemokines
Degranulation - releases toxins onto surface of parasites
Cytokine production - drives inflammation