Immunology 3 Flashcards
Outline the importance of vaccination?
- Individual and herd welfare
- Disease control
- Disease eradication
- Altruism (protect those that cannot be vaccinated)
List animal factors to consider regarding vaccination
- Pathogen and protective immune response required
- Age of animal/colostral Ab decline/immunosenescence
- Health
- Management
- Timing of vaccination
- Previous disease/vaccination history
- Pregnancy status
List vaccine factors to consider regarding vaccination
- Content of vaccine (strains, adjuvants)
- Types of vaccine available
- Route of vaccination
- course of vaccination
- Efficacy
- Registration license
- Adverse effects/risks
What does DIVA stand for?
Differentiating Infected from Vaccinated Animals
Give examples of passive immunisation methods
- Colostrum
- Serum or purified Ig
Describe the features of passive immunisation
- Preformed antibodies
- Rapid protect but short-term (days)
What protection does colostrum provide?
- Passive immunisation
- Protection against local pathogens that the dam has been exposed to
Describe serum or purified Ig used for immunisation
- Donor animals hyper-immunised against specific pathogen
- Serum collected/Ig purified
- Administered to deficient animals
What are the risks of using antibody-rich serum for immunisation of animals?
- Serum sickness
- Immune complex disease (hypersensitivity)
- Immune responses against donor Igs
- Inadvertent disease transfer
Outline the features of active immunisation
- Vaccine antigen
- Commonly with adjuvants
- Induces long-term protective immunity
- Memory cells formed
- Protects animal when exposed to pathogen in infectious form
- Multiple routes of adminstration
Via what routes can vaccines be administered?
- Systemic (IM, subcut, ID)
- Mucosal (oral, aerosol, intranasal)
- Water (form of mucosal used for fish)
Outline the key features of mucosal vaccines
- Local to site of pathogens invasion
- Immunity generally short-lived (weeks)
- Require frequent boosters
Give examples of vaccine adjuvatns
- Aluminium and calcium salts (aka alum, safe)
- Microbial products (bacterial cell wall extracts/fragments aka Freunds)
- Synthetic agents (Carbopol, ISCOMs)
- Exogenous cytokines (IL-2 in tetanus vaccine)
How do vaccine adjuvants function?
- Enable slow release of vaccine antigens into body to enhance immune recognition and response
- Stimulate immune response non-specifically (Th2)
In what types of vaccines are adjuvants commonly used?
Non-living/inactivated
What is meant by “correlate of immunity”?
Where the details of protective immunity following infection has been characterised in the host animal
Why is the “correlate of immunity” important?
Want vaccine to generate immune response as similar as possible to the natural response i.e. if pathogen is rarely found outside of cell, then stimulating high levels of antibody is not so useful
What are the preferred responses to vaccination?
- Generate protective immune response
- Ling term immunity
- Stimulation of long-lived memory
- Rapid secondary response if re-exposed
- Ideally combination of all of above
List the different types of vaccine
- Live (attenuated)
- Marker/gene deletion mutants
- Subunit
- Multivalent
- recombinant protein
- Naked DNA
How are inactivated vaccines killed?
Heat, sometimes chemicals
What is a subunit vaccine?
Selected proteins or peptides of pathogen, only used where immune response is well characterised and know what subunit will lead to response on re-exposure
What is a multivalent vaccine?
Multiple pathogens in one administration
What is a recombinant protein vaccine?
One where the desired gene has been expressed in vitro and the protein purified
What is a naked DNA vaccine?
One where you transfect in vivo host cells, stimulating immune response as host cell produces the immunogenic protein
What is a benefit of a whole, attenuated pathogen vaccine?
Mutants selected in vitro to have reduced virulence but retain antigenicity, therefore are safe but will get response to virulent strains
What are benefits of deletion mutant, and live vectored vaccines?
DIVA potential, correct CMI or Ab response
What is a disadvantage of deletion mutant and live vectored vaccines?
Potential reversion to virulence (e..g by recombination with field strain), may cause disease in the individual and spread to others that have not be vaccinated
What are the outcomes of cell mediated immunity (CMI) to live attenuated vaccines?
- Vaccines infect host cells to a limited degree
- Endogenous processing of antigens and presentation by APC, MHC class II
- Infection of target cells and presentaiton by MHC class I in vivo follows
- Results in CTL recognition of virus and memory cells established (Th1 to enhance CTL)
- Humoral immunity also generated
- Re-exposure of vaccinated host to pathogen results in anamnestic response
Give an example of a gene deletion mutant vaccine
Infectious Bovine Rhinotracheitis (BHV-1) vaccine
Describe inactivated vaccines
- Killed whole/part organisms
- Cannot replicate so no clinical disease
- Retain some antigenicity
- Ag presentation to Th1 and Th2 results in promotion of B cells (antibody), likely to stimualte more Ab and less CTL
What is an advantage of inactivated vaccines?
No danger of reversion to virulence
What is a disadvantage of inactivated vaccines
Only structural proteins present, need an adjuvant as are less immunogenic
Describe the outcomes of inactivated vaccines
- Antibody production primarily
- Taken up by APC, proteins processed exogenously
- Processing and presentation by MHC II
- Leads to Th2 response, cytokines enhance differentiation of B cells to plasma cells, specific Ab secreted
- Memory cells established
- Some (less efficient) CMI
- Re-exposure leads to anamnestic response
Give examples of inactivated vaccine types
- Whole pathogen
- Inactivated toxins
- Subunit vaccines (e.g. flu haemaglutinin)
- Subcellular fragments (e.g. cell wall extracts, require adjuvant)
- Specific recombinant gene products
- Naked DNA
Outline the vaccine type and vaccination protocol for Feligen RCP
- Multivalent containing feline FIE (parvovirus), Rhinotracheitis virus, Calicivirus
- 1ml SC >9 wks (V1)
- 3-4 weeks later V2
- Maternal Ab suspected, V3 at >15 wks
- Revaccination 1x annually
Outline the vaccine type and vaccination protocol for Infectious Bovine Rhinotracheitis
- Live deletion mutant, marker
- V1: 2ml IM neck, >3mo
- 3 weeks later V2
- revaccination 2x annually
Outline the vaccination protocol of avian rhinotracheitis
- Mucosal: eye or nose drop, or corase spray at 30-40cm
- > 1d old
- V1 in broilers, future layers, breeders
- Future layers and breeders before lay onset V2 with inactivated vaccine
Compare hypoimmunisation and vaccination
- Vaccination aims to increase immune response to an antigen/pathogen
- Hypoimmunisation aims to reduce response (and so decrease clinical signs)
How does hypoimmunisation work?
- Identify allergen
- Administer allergen to bias immune response away from IgE and towards IgG
- Reduces the clinical signs
What are the benefits of vaccination?
- Protection of the individual
- Protection of the herd
- Reduction of clinical signs in infection