Vaccination L9 (Virology) Flashcards
Immune response to viral infections
THREE LINES OF DEFENSE
First Line of defense
§ ? barriers
§ ? barriers
§ ?
§ Second Line of defense
§ ? immunity
§ Third Line of defense
§ ? immunity
Immune response to viral infections
THREE LINES OF DEFENSE
First Line of defense
§ chemical barriers
§ mechanical barriers
§ reflexes
§ Second Line of defense
§ innate immunity
§ Third Line of defense
§ adaptive immunity
Innate immune system
Pathogen recognition
§ Recognition of ?-associated ? patterns (PAMPs) by Pattern recognition receptors (PRR) on ? cells such as macrophages and ? cells
Binding of PRRs (pattern recognition receptors) with PAMPs (pathogen-associated molecular patterns PAMPs) triggers the release of ? (chemical messengers)
§ ?
§ ?
§ As a result, ? occurs and more ? cells will be recruited
§ Direct recognition by ? results also in ‘eating the ?’ = phagocytosis
Innate immune system
Pathogen recognition
§ Recognition of pathogen-associated molecular patterns (PAMPs) by Pattern recognition receptors (PRR) on immune cells such as macrophages and dendritic cells
Binding of PRRs (pattern recognition receptors) with PAMPs (pathogen-associated molecular patterns PAMPs) triggers the release of cytokines (chemical messengers)
§ interleukins
§ interferons
§ As a result, inflammation occurs and more immune cells will be recruited
§ Direct recognition by phagocytes results also in ‘eating the invaders’ = phagocytosis
Innate immune system
§ Infected cell recognition
§ ? Killer cells (NK cells): recognize ? expression of ? molecules on the surface of ? infected cell -> production of destructive ? -> leads to ?
APOPTOSIS = programmed ?
§ Characteristic changes in cell morphology causing cell death with inflammation
§ Changes include cell ?, blebbing, nuclear ?, and formation of ? bodies which are then ?
Innate immune system
§ Infected cell recognition
§ Natural killer cells (NK cells): recognize altered expression of major histocompatibility class molecules on the surface of virus-infected cell -> production of destructive proteins -> leads to apoptosis
- a natural killer cell recognizes MHC type I, on a healthy cell and does not kill it
- an infected cell that doesn’t present MHC I is killed
(MHC type I detects changes on an infected cell so it knows something is wrong so it leads to the production of destructive proteins and apoptosis of these infected cells)
APOPTOSIS = programmed cell death (cell clean up)
§ Characteristic changes in cell morphology causing cell death with inflammation
§ Changes include cell shrinkage, blebbing, nuclear fragmentation, and formation of apoptotic bodies which are then phagocytosed
Adaptive immune system
- So this is another one in which you can find the pathway for “cellular” immunity as well as “humoral” immunity.
- And so if pathogens, viruses or antigen spikes or viruses are found, they’ll be found.
So T lymphocytes will recognize these present antigen pieces. - and you will have either cellular immunity or humoral immunity with a potential for long-term memory WHICH survives for a long time
- thus induction of the same immune response which is the basic principle of vaccination
!! If we wouldn’t have long term memory, vaccination would never be something we can do !!
Immunoprophylaxis
= Prevention of disease by the production of ? or ? immunity
adaptive immunity is divided into naturally acquired and artificially acquired
- naturally acquired
a. active: antigens enter the body naturally; body induces ? and specialized ?
b. passive: antibodies pass from mother to fetus via ? or to infant via the mother’s milk
- artificially acquired
a. active: antigens are introduced in ?; body produces > and specialized lymphocytes
b. passive: preformed ? in immune serum are introduced by ?
Immunoprophylaxis
= Prevention of disease by the production of ? or ? immunity
adaptive immunity is divided into naturally acquired and artificially acquired
- naturally acquired
a. active: antigens enter the body naturally; body induces antibodies and specialized lymphocytes
b. passive: antibodies pass from mother to fetus via placenta or to infant via the mother’s milk
- artificially acquired
a. active: antigens are introduced in vaccines; body produces antibodies and specialized lymphocytes
b. passive: preformed antibodies in immune serum are introduced by injection
Immunoprophylaxis
Passive immunization
§ ? transfer of antibodies from mother to ?
§ Administering ? (“artificial”)
Active immunization
§ ? infection
§ ? (“artificial”)
Immunoprophylaxis
Passive immunization
§ vertical transfer of antibodies from mother to fetus
§ Administering antibodies (“artificial”)
Active immunization
§ natural infection
§ Vaccination (“artificial”) -> produces B and lymphocytes
Passive immunization
§ vertical transfer of antibodies from mother to fetus -> called passive as its “temporary” and not long term.
In some cases we will administer “hyperimmune serum” too quickly, to help an animal overcome an initial infection.
Sometimes that makes a difference in your prognosis for your animal to provide an hyper immune serum
Vaccination
§ Primary vaccination ~ ? infection
§ Lag phase before response
§ Response to the second vaccine is faster
** -> Leads to a more focused, ?, and ? lasting immune response **
- vaccination relies on primary and secondary response.
- So the second response is more focused on the stronger response with potentially long-lasting immune responses. (go through bacteria notes for this slide)
- Attenuated comes actually from the passage of viruses multiple times in embryo nature, chicken, eggs and so on.
- And attenuation reduces the virulence of the virus.
- toxoid vaccines think of this.
Vaccination
§ Primary vaccination ~ first infection
§ Lag phase before response
§ Response to the second vaccine is faster
** -> Leads to a more focused, stronger, and long lasting immune response **
- vaccination relies on primary and secondary response.
- So the second response is more focused on the stronger response with potentially long-lasting immune responses. (go through bacteria notes for this slide)
- Attenuated comes actually from the passage of viruses multiple times in embryo nature, chicken, eggs and so on.
- And attenuation reduces the virulence of the virus.
- toxoid vaccines think of this.
Viral vector vaccines
- mRNA vaccines ‘teach our cells how to make a (piece of a, specifically spikes) protein that triggers an ? response inside our bodies.
That response, which produces ?, is what protects us. - Viral mRNA does not interact with host cell ? (only retroviridae can do this) and ? breaks down after the production of the ? proteins.
(recall: ONLY retroviridae can do this bc it has reverse transcriptase -> generates a provirus (goes inside nucleus)
Viral vector vaccines
- mRNA vaccines ‘teach our cells how to make a (piece of a, specifically spikes) protein that triggers an immune response inside our bodies.
That response, which produces antibodies, is what protects us. - Viral mRNA does not interact with host cell DNA (only retroviridae can do this) and mRNA breaks down after the production of the spike proteins.
(recall: ONLY retroviridae can do this bc it has reverse transcriptase -> generates a provirus (goes inside the nucleus)
How Coronavirus Hijacks Your Cells
- the proteins covering the coronavirus (spike proteins) attach to ? on the outside of cells (i.e. cell ?), like a lock and key, allowing the virus to enter the ?.
- upon entry, the virus sheds its protein coat, releasing the RNA genome in the cell’s ?. the cell’s ribosomes can’t tell the difference between the virus mRNA and cell MRNA so it makes a viral protein (polymerase) necessary to make ? of the virus.
- the polymerase protein makes copies of the ? genome and ? instructions to make more ? proteins.
- the cell’s ribosomes keep churning out lots of ?, ?, membrane and ? viral proteins.
- the cell has made all the pieces necessary to make more ? particles.
- all of the pieces of the coronavirus are now ?.
- the mature fully assembled new virus is ready to ? the cell.
- the newly made coronaviruses exit the cell to go on and infect more cells, repeating the same process over and over.
How Coronavirus Hijacks Your Cells
- the proteins covering the coronavirus (spike proteins) attach to proteins on the outside of cells (i.e. cell receptors), like a lock and key, allowing the virus to enter the cell.
- upon entry, the virus sheds its protein coat, releasing the RNA genome in the cell’s cytoplasm. the cell’s ribosomes can’t tell the difference between the virus mRNA and cell mRNA so it makes a viral protein (polymerase) necessary to make copies of the virus.
- the polymerase protein makes copies of the RNA genome and mRNA instructions to make more viral proteins.
- the cell’s ribosomes keep churning out lots of spike, nucleocapsid, membrane and envelope viral proteins.
- the cell has made all the pieces necessary to make more viral particles.
- all of the pieces of the coronavirus are now assembled.
- the mature fully assembled new virus is ready to exit the cell.
- the newly made coronaviruses exit the cell to go on and infect more cells, repeating the same process over and over.
how mRNA vaccines work
- injection of the mRNA vaccine allows the mRNA to enter the cell and find ?
- the mRNAs in the vaccine deliver the instructions to make the coronavirus ? protein
- your immune cells recognize that ur cells shouldn’t be making ? proteins, so they produce ? to fight off perceived invaders.
- once made, the antibodies wait for the opportunity to attack the real spike protein if you are infected by the coronavirus in the future.
how mRNA vaccines work
- injection of the mRNA vaccine allows the mRNA to enter the cell and find ribosomes
- the mRNAs in the vaccine deliver the instructions to make the coronavirus SPIKE protein
- your immune cells recognize that ur cells shouldn’t be making SPIKE proteins, so they produce antibodies to fight off perceived invaders.
- once made, the antibodies wait for the opportunity to attack the real spike protein if you are infected by the coronavirus in the future
- spike and not a random piece of virus as only spikes replicate
Canine core vaccines
§ Core vaccine: vaccines as those which ALL dogs, regardless of circumstances or geographical location, should receive. Core vaccines protect animals from severe, life-threatening diseases that have global distribution.
§ “DHPP”vaccine
- the aim is to protect these animals from very severe, life-threatening diseases.
- core vaccines: canine distemper, adenovirus, parvovirus, rabies and influenza.
- RABIES should be considered core for those species, even if there is not always a legal requirement.
- state rabies vaccination laws are diff. for diff. states (e.g. booster shot at diff. intervals)
- And remember I told you rabies is 100% preventable through vaccination and also through vaccination in your candidae population - So it contributes to a reduction of the circulation of viruses in the reservoir.
- And don’t wait till you see symptoms. Don’t hesitate in there and assure that you know that for rabies we have a very good vaccine developed.
- RABIES It’s almost always fatal, but it’s 100% prevent preventable.
IN CATS
core vaccines in cats: feline herpes virus that causes the feline renal trachiti? smtms called renal trachitis virus, feline pulnipulpea virus? and also feline calici virus.
Antiviral drugs
Viruses are intimately dependent on the ? pathways of their host cell for replication –>
Most agents that interfere with virus replication are ? to the cell!!
§ Acyclovir: inhibits viral DNA replication without affecting ?
§ Interferon: inhibits ? of viral RNA into protein
Antiviral drugs
Viruses are intimately dependent on the metabolic pathways of their host cell for replication –>
Most agents that interfere with virus replication are TOXIC to the cell!!
§ Acyclovir: inhibits viral DNA replication without affecting host cell processes
§ Interferon: inhibits translation of viral RNA into proteins
pic:
VIRAL BINDING AND ENTRY
If a virus cannot ENTER in the susceptible host cell, it cannot cause any infection of that cell, let alone lead to a clinical syndrome.
- if the first step i.e. viral binding and entry is blocked then easier to stop everything such as messing up the metabolism of the cell.
- Because once the viruses are inside the cell, they’ll make use of the different metabolisms in the cell.
RNA PRODUCTION
But we could interfere with, for example, the different stages in the synthesis.
One of them being the RNA production, there are drugs that PREVENT the VIRAL ENZYME from COPYING its genes.
PROTEIN PRODUCTION
So the viruses will not be able to build all their different building blocks and potentially an essential gene, such as an integrase or a reverse transcriptase that they might not continue to build.
thus this cell by itself might have lysis it might still be recognized by the immune system as something has happened to the cell But at least you didn’t have a replication of the virus or not the complete release of virus particles.
