Innate Immunity Flashcards
Characteristics of the innate immune system
Limited specificity Response to antigen is independent Immediate maximal response No immunological memory Phylogenetically ancient
Characteristics of the adaptive immune system
Highly specific Response is antigen dependent Lad time between exposure and maximal response Immunological memory Recent development
What is the main function of the immune system
Self/non-self discrimination
List various types of innate immune barriers
Anatomical
Humoral
Cellular
How does complement work?
Activate plasma proteins
Increase vascular permeability
Recruitment, lysis and opsonisation of bacteria
Types of cellular communication
Contact dependent
Paracrine
Synaptic
Endocrine
Cytokines released by activated macrophage
Il-1B TNF-a IL-6 CXCL8 IL-12
Process of cellular communication
Receptor-ligand binding
Signal transduction (2nd messengers)
Cellular responses
Changes in gene expression
How do cells of the innate immune system recognise pathogens?
They express receptors (PRRs) which specifically recognise Pathogen Associated Molecular Patterns (PAMPs)
Why are they called pattern recognition receptors?
The surfaces of micro-organisms bear repeating patterns of molecular structure
- viruses = dsRNA
- bacteria = unmethylated CpG repeats + lipopolysaccarides on surface
Why are PAMPs ideal for innate immune recognition?
- only produced by microbes (not host)
- invariant
- essential for microbial survival (limits mutant non-detection)
- constitutive and conserved products of microbial metabolism
Where can TLRs be found?
On the cell membrane or in the endosome
Role of dendritic cells in immunity
- reside in peripheral tissue
- monitor environment for presence of pathogens by using PRRs
- takes up pathogens by phagocytosis
- protein is processed into antigenic peptides + presented at cell surface by MHC 1/2
Role of neutrophils
Phogocytic effector cells
- recognise opsonised bacteria
- direct recognition of pathogens
What do NOD proteins stand for?
nucleotide-binding oligomerization domain
