Lecture 24-26 Flashcards
1
Q
What are the types of vaccines?
A
- Live attenuated
- Inactivated
- Subunit
- Toxoid
- Conjugate
2
Q
Classes of vaccines
A
- Live attenuated-weaked strain of whole pathogen
- Inactivated-Whole pathogen killed or inactivated with heat, chemicals, or radiation
- Subunit-immunogenic antigens
- Toxoid- innactivated bacterial toxin
- Conjugate-capsule polysaccharide conjugated to protein
3
Q
What is autoimmunity?
A
- An inability to recognize itself
- Normally the body builds tolerance to self
- Occasionally an individual loses tolerance and mounts an abnormal attack against host tissues
- Normally, B cells that escape from the negative selection process cannot be activated bc they require a cognate T helper cell
- Sometimes, pathogens make similar molecules to those of our own cells using molecular mimicry
- B cells and T cells respond to the non-self part of the epitope but may produced antibodies to the part that looks like self
- These go on to attack tissues and damage the body
4
Q
Why is it important to treat strep throat
A
- Streptococcus pyogenes makes a protein called M protein
- Part of this protein very similar to a cardiac protein
- The cardiac like epitope may be encountered by an escaped self reacting B cell
- The cognate T cell may recognize flanking non self protein and activate the B cell
- The B cell responds makes plasma cells that secrete antibodies to the cardiac protein
-Damage to the host cardiac tissue occurs
Rheumatic fever can lead to scarring of heart valves
5
Q
Influenza virus
A
- A negative strand RNA virus
- Influenza A virus: one of the most common life threatening viruses of the wester world
- Influenza B virus
- Narrower host range than Influenza A
- Can cause short serious disease but mutates much more slowely
- Influenza C virus
- Narrower host range than Influenza A
- Can cause serious disease but does not spread as easily
6
Q
Influenza pandemics
A
-Pandemic mortality
- spanish flu
- Asian flu
- Hong Kong flu
- Swine flu
H7 N9
7
Q
What is the difference between flue and the cold?
A
-fever with influenza
-Sever headache
-muscle aches and pains
exhaustion
8
Q
Virion genome
A
- 8 negative sense RNA segments
- each is coated with nucleocapsid proteins (NPs)
- Each encodes 1 protein
- 2 segments undergo splicing to encode 2 further proteins
- Each segment is packaged with an RNA dependent RNA polymerase complex
- During viral assembly in an infected cell, segments are packed precisely
- They link to each other to arrange themselves
- Each segment lines up like a bundle of sticks
- Tiny molecular extenstions seem to connect these sticks
9
Q
Advantages of a segmented genome
A
- One of the most dangerous aspects of influenza virus is its ability to continually change its antigenic determinants
- Segmented genomes allow for reassortment of genetic information generating drastically new strains more quickly than viruses with non segmented genomes
-poliovirus
10
Q
The H bit
A
- Hemagglutinin
- There are 18 HA subtypes
- Forms a trimer complex each with an N-terminal fusion peptide
Allows fusion of the viral membrane with the host cell membrane
- HA c TERMINAL domain recognizes and binds to host cell sialic acid receptor
- Triggers uptake of virion by endocytosis
- Endocytic vesicle acidifies and produces a conformational change that exposes the N terminal fusion peptide
- Fusion of host and viral membranes can now take place
- Triggers release of the genome cargo into the host cytosol
11
Q
Influenza attachment to receptor
A
- Viral segments travel to nucleus and enter nuclear pores
- Attached viral RNA polymerase synthesizes + strand RNA
- mRNA travels to cytoplasm for translation to viral proteins-these are processed by the ER/ Golgi and sent to the host cell membrane
12
Q
The N bit
A
- Envelope proteins and viral genome packages travel to cell membrane for packaging into new virions
- Within the cell membrane, envelope proteins assemble around the genome and martix proteins
- Virion then buds out of the host cell
- Neuraminidase cuts the virion loose from host glycoproteins to release it to the extracellular space
- There are 11 neuraminidase N variants
13
Q
Drifting and shifting
A
- Drifiting
- The ability of influenza virus A or B to mutate and change slightly
- Usually bc of RNA replication errors in HA and NA genes - Shifting
- A big change in the structure of the flu virus
- Can be cause by jumping of the virus into a new species
- Can be caused by re assortment of the genes from 2 different viruses mixing in a single host (pig)
14
Q
Neutralizing antibodies
A
- Crucell’s neutralizing antibodies at work
- Leading research in the use of broadly neutralizing monoclonal antibodies that are active against all strains
- How to target the immune system to raise broadly neutralizing antibodies as a vaccine strategy
15
Q
HIV-a retrovirus
A
- Retroviruses
- A major class of RNA viruses
- Reverse the normal order of snythesis to copy their RNA into a ds DNA
- Integrated into the host genome
HIV is in the lentivirus group of viruses LENTI-SLOW)
- cause infections that progress over many years
- Most famous HIV
