Immunology 4 & 5- Response to infections Flashcards
What do RNA Viruses rely on to evade the immune system?
Antigenic variation
What do DNA viruses rely on to evade the immune system?
Immunoregulatory genes and Antigenic variation
What are the Immunoregulatory genes allowing DNA viruses to evade the immune system?
-Proteins that block interferon signaling
- Proteins that interfere with MHC-1 associated Antigen presentation
- Evasions of NK cells
- Alterations in humoral immunity (non-neutralizing or slower neutralizing immunity)
What are the 5 pathogens?
- Virus
- Bacteria
-Protist - Helminth
- Fungus
What is homeostasis
balance between the pathogens and immune response
What happens if there is too much immune reponse?
Immune disease, hypersensitivity, autoimmunity
What happens when there is too much pathogen disease?
Infectious disease?
Location/size of viral infection
obligate intracellular
20-400 nm
Location/size of bacterial infection?
Intra or extracellular
0.2-12 um
Location/size of protist infection?
Intra or extracellular
1-50um
Location/size of helminth infection?
Extracellular
3-1000 mm
Location/size of fungus infection?
intra or extracellular
2-200 um
Pathogenesis of fungus infection?
- Enzyme production
- Direct cell/tissue damage
- Immunopathology
Pathogenesis of viral infection?
- Direct Cell damage
- DNA damage
- Immunopathology
Pathogenesis of bacterial infection?
- Direct cell Damage
- Toxin Production
- Immunopathology
Pathogenesis of protist infection?
- Direct cell damage
- Immunopathology
Pathogenesis of helminth infection?
- Competition for resources
- Direct tissue damage
- Immunopatholgy
What are the innate immune defenses?
- Epithelial barriers
- Secretions
- Endogenous microflora
- Resident phagocytes
- Pattern recognition receptors
What are some epithelial barriers?
Skin
respiratory epithelium
Enterocytes (gut epithelium)
What are secretions of the innate immunity?
Mucus
Sweat
Acid
Enzymes
defensins
polyreactive Antibodies
surfactant
What are the necessary innate immunity pattern recognition receptors
PAMPs
PRRs
What are PRRs?
Pattern recognition receptors
What are PAMPs?
Pathogen-associates molecular patterns- get recognized by the PRRs
Ex: what does TLR1 recognize?
Triacyl lipopeptide
Ex: what does TLR2 recognize?
Peptidoglycan
Lipoteichoid acid
lipoprotein
What are the TLRs that are in the endosome? why are they there?
TLR3, 7, and 9
- Because they recognize RNA/DNA patterns so they must be intracellular
- All recognize viruses
What are the adaptive immune responses?
-CMI
- Humoral immunity
What is CMI? What does it do and what type of pathogen does it respond to?
Cell-mediated immunity
- Mediates by Th1 to help cytotoxic t-cells respond
- important for intracellular pathogens
What does humoral immunity do? What type of pathogen does it respond to?
- Mediated Th2 response to activate B cells to produce antibodies
- Good at controlling extracellular pathogens
What are the steps of a virus infecting a cell?
- Bind to VAP
- Viron enters the cell (3 ways)
- Nucleic acid released into cytoplasm
- Replication
- Protein production
- Assembly
- Release
- Spread
What triggers the innate immunity response to a viral infection?
- Recognition of viral patterns by PRRs
- Cells damage
What PRRs recognize viral patterns?
- RIG-1
- MDA5
- TLR 3, 7, 8, 9
What PRRs recognize viral patterns in the cytoplasm?
- RIG-1
- MDA5
What PRRs recognize viral patterns in the endosome?
- TLR 3, 7, 8, 9
What is an interferon?
Glycoproteins
- Signaling proteins
- Regulate protein expression
What are the three types of interferons?
- Type 1
- type 2
- type 3
What are the type 1 INF and where are they produced? How quickly are they produced?
INF alpha- produced by dendritic cells
INF beta- produced by ANY virally infected cell
- Produced upon binding of TLR 3, 7, 8, 9, RIG-1, or MDA-5 and act on near by-cells
- Within hours (before antibodies)