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Immunology and Virology > Vaccines against infectious agents > Flashcards

Vaccines against infectious agents Flashcards

Immunology 5 - Vaccines against infectious agents

1
Q

What is a vaccine?

A

Biological product that can be used to safely induce an immune response for protection against infection and/or a disease on subsequent exposure to a pathogen

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2
Q

How do vaccines work?

A

Most induce humoral immunity.
Antibodies are important to prevent infection by neutralising and clearing microbes before they can cause illness in the host.
T cells are important in eliminating virus-infected cells and controlling disease development.
Longevity of vaccine-induced protection varies greatly

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3
Q

Active Immunity

A

Protection produced by a persons own immune system
Immune system is stimulated by an antigen to produce antibody-mediated and cell-mediated immunity.
Lasts for many years, even a lifetime

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4
Q

Passive Immunity

A

Protection gained when receiving antibody or antitoxin produced by one animal or human.
Is temporary

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5
Q

What are live attenuated vaccines?

A

Wild viruses/bacteria that have been weakened.
Virus is passed through many generations of cells in the lab to pick up mutations which weaken it - cant cause disease in the body.
Target your bodys immune system directly.
.

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6
Q

Examples of live attenuated vaccines:

A

measles. mumps, rubella vaccine, varicella vaccine

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7
Q

Benefits of live attenuated vaccines

A

s contain a
live pathogen- immune system reacts well to them and will typically remeber the pathogen for a very long time - booster shots not always needed.

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8
Q

How do attenuated vaccines create immunity

A

antigen presenting cell - fragmented viral protein displayed by cell
Immune helper cells trigger an immune response.
Body creates army of B-cells to produce antibodies against viruses.
Antibodies bind to virus preventing entry into cells
Memory cells created to launch attack if the body encounters the virus
Infected cells recognised and destroyed

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9
Q

What are inactivated Vaccines

A

Wild viruses/bacterria that have been inactivated.
Wild virus killed by chemicals/heat so it cant replicate/cause disease and is safe for immunodeficient people.
Target your bodys antibody production
Often requires multiple doses

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10
Q

Benefits of inactivated vaccines

A

Can be mass produced
Relatively inexpensive to make

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11
Q

How do inactivated vaccines work?

A
  1. inactivated vaccine delivered by syringe/ orally
  2. Vaccine virus or bacteria taken up by antigen-presenting cells
  3. Vaccine chopped up into pieces (antigens)
  4. antigens developed on cell surface where they can be recognised by immune system
  5. immune helper cells trigger an immune response
  6. Body creates army of B-cells to produce antibodies against wild virus/bacteria
  7. Antibodies bind to virus/bacteria and present entry into cells
  8. Antibody levels fade with time and usually additional shots are needed
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12
Q

What are sub-unit vaccines

A

Use a portion of bacteria or virus to cause an immune response independent of its virus/bacteria of origin. Elements of subunit vaccines can be proteins, polysaccharide chains or a combination.

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13
Q

Subunit vaccines: Protein vaccines

A

Viral proteins are isolated in a lab, mixed with an adjuvant immune-system stimulator and injected into the body to cause an immune response without the virus that makes you sick

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14
Q

sub-unit vaccines mechanism of producing immunity

A
  1. Vaccine released into your body.
  2. Protein taken up by antigen-presenting-cell and displayed on surface as antigen
  3. Immune helper cells identify antigen and trigger an immune response.
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15
Q

Benefits of sub-unit vaccine

A

Contain pieces of a pathogen not the whole organism - cant cause infection.
Suitable for people who cant get live vaccines

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16
Q

Polysaccharide and conjugate vaccines - How are they made

A

Some bacteria use polysaccharide chains as a disguise from the immune system.
Protein conjugate attached to the polysaccharide n the lab and injected into the body to teach it to recognise the polysaccharide disguise as a harmful invader

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17
Q

Polysaccharide and conjugate vaccines - How they cause immunity

A
  1. Vaccine released into the body.
  2. Vaccine taken up by antigen presenting cell and displayed on surface as antigen
  3. Immune helper cells identify antigen and trigger immune response
18
Q

Immune responses to polysaccharide vaccines

A

Induce antibody-producing plasma cells by cross-linking the B cell receptor (BCR).
Affinity maturation of antibody response and induction of memory B cells dont occur.
No affinity maturation
No immune response in infants more than 2 years old

19
Q

Immune responses to protein-polysaccharide conjugate vaccines

A

Can engage T cells that recognise the carrier protein
Can engage B cells that recognise the polysaccharide
T cells provide help to B cells leading to affinity maturation and production of plasma and memory Bcells.
Long-lived antibody production
Improved responses in infants

20
Q

Recombinant Vaccines

A

Viruses/bacteria/cells created in labs that carry DNA coding for surface proteins from a virus/bacteria.
Can be injected into the body to cause immune response to the viral surface proteins harmlessly

21
Q

Recombinant Vaccines mechanism to produce immunity

A
  1. Vaccine released into the body
  2. Vaccine taken up by antigen presenting cell and displayed on surface as antigen
  3. Immune helper cells identify antigen and trigger immune response.
22
Q

What is a viral vector vaccine

A

Made of a small section of a virus genetic material.
Viral capsule or shell from another virus carries the gene safely to your cells.

23
Q

Viral Vector Vaccine - Vaccine Target

A

AstraZeneca and Jhonson&Jhonson COVID viral vector carry genetic code for the spike protein and build immunity against invaders carrying it on their surface

24
Q

Viral Vector Vaccine benefits

A

Usually trigger a strong immune response.
Only one dose is typically needed - booster may be needed to maintain immunity.

25
Q

How does a viral vector vaccine work to create immunity?

A
  1. Viral vector vaccine delivered by syringe
  2. Viral vector fuses with cell membrane releasing genetic code
  3. Instructions are read and cell makes target protein
  4. Cell presents target protein on surface where its found by the immune system
  5. Immune helper cells trigger on immune response
  6. Body creates army of B-cells to produce antibodies against target protein
  7. antibodies tag cells displaying target protein for distruction
  8. Memory cells related to launch an attack if the body encounters the virus
  9. Infected cells recognised and destroyed
26
Q

What are Toxoic vaccines?

A

Neutralise toxic activity created by bacteria neutralising activity which normally makes you sick.

27
Q

What is the target of toxoid vaccines?

A

toxic acitvity, creating an antibody response to that toxin

28
Q

Benefits of Toxoid vaccines

A

Especialy good at preventing certain toxin-mediated disease.
Booster shots recommended every 10 years or so

29
Q

Examples of toxoid vaccines

A

tetanus vaccine, diphtheria vaccine

30
Q

How do toxoid vaccines work to create immunity

A
  1. Toxoid vaccine released into the body
  2. Toxoid cannot bind to cells as toxins do
  3. Toxoids can trigger the similar immune response as bacterial toxinx. Bacterial toxins enter and eventually destroy cells.
  4. Immune helper cells trigger an immune response.
  5. Body creates army of B-cells to produce antibodies against virus
  6. Antibodies bind to toxoid /toxin and mark for destruction
  7. Antibody levels fade with time and usually additional shots are needed
31
Q

What is mRNA vaccine?

A

Made of a small section of a virus’ genetic material
Insoluble nanoparticle capsule carries gene safely to your cells.

32
Q

mRNA vaccine target

A

Carries the genetic blueprint for the spike protein.
Body will make this protein and build immunity against any invaders carrying it on their surface.

33
Q

mRNA vaccine benefits

A

Able to create a lot of vaccines fast.
Technology is very adaptable - can change mRNA in the formulation to target a new antigen and can make high-quality vaccine material relatively quickly.

34
Q

How do mRNA vaccines work to create immunity?

A
  1. Nanoparticle RNA delivered by syringe.
  2. Capsule fuses with cell membrane releasing genetic code.
  3. Instructions are read and cell makes target protein.
  4. Cell presents target protein on surface, where its found by the immune system.
    Fragmented target protein released when cell dies when the target protein is displayed…?
  5. Immune helper cells trigger on immune response.
  6. Body creates army of B-cells to produce antibodies against target protein
  7. Antibodies tag cells displaying target protein for distruction
  8. Memory cells created to launch an attack if the body encounters the virus.
  9. Infected cells recognised and destroyed.
35
Q

Overview of VLP-based vaccine expression, purification and forumlation (Process of manufacturing VLP-Based vaccine - Production stage)

A

Production: Cloning of viral structural genes of interest and expression of viral proteins with self-assembling ability in suitable expression (HEK293T cell line- mammalian expression system).VLPs collected in the from of particles that dont have infectious properties

36
Q

Overview of VLP-based vaccine expression, purification and formulation (Process of manufacturing VLP-Based vaccine - Purification stage)

A

Downstream processing such as clarification, purification and polishing to finally obtaining purified intact VLPs with no residual host debris

37
Q

Overview of VLP-based vaccine expression, purification and formulation (Process of manufacturing VLP-Based vaccine - Formulation stage)

A

Adjuvant and additional ingredients are added to vaccine formulation to finally achieve a safe, efficient and effective product for vaccination.

38
Q

What is a VLP based vaccine

A

Type of subunit vaccine based on virus-derived proteins assembled to form a particle.

39
Q

Generation of an immune response from a VLP vaccine - inducing humoural immunity

A

Adaptive immune activation induced by VLP-based vaccine.
VLP-based vaccine taken up by Antigen presenting Cells such as dendritic cells.
Phagoycytosed VLP-based vaccie processed and presented by both MHC-II and MHC-1 for detection by CD4+ and CD*+ Tcells
Humoural immune response inducted by B cells interacting with CD4+ T helper cells to uptake VLP-based vaccine by B-cell receptor. Interaction between CD4+ TH cells and B cells occurs for sufficient secretion of IgG antibodies by plasma cells as well as generation of B memory cells.

40
Q

Generation of an immune response from a VLP vaccine - inducing cellular immunity

A

Immature CD8+ cytotoxic T lymphocyte proliferate and differentiate into effector and specific memory Lymphocytes.
Effector CD4+TH cells increase antigen presenting by secreting cytokines and assist activated lymphocytes.

41
Q

Herd immunity

A

Important feature of vaccine-induced protection.
Susceptible individuals - those who have not yet been immunised or cant be, those who did not get sufficient immunity from the vaccine, those who need but have not recieved booster vaccines.

Immunology and Virology (7 decks)

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