Vaccines

BACK TO IMMUNOLOGY BACK TO HOST INVASION BY MICROORGANISMS

Why Vaccinate?

• To protect against infectious diseases

• Where there is no effective treatment once infected
  • E.g. FeLV, FIV

• Where disease is life-threatening
  • E.g. Canine Parvovirus

• To prevent the spread of disease
  • E.g. Rabies, FMDV

How do we vaccinate?

• Usually by subcutaneous injection for systemic protection (IgG)

• For mucosal immune reponse, intranasal administration is best (IgA)

What do we vaccinate with?

Passive Immunisation - Copyright nabrown RVC

Passive immunisation

• Administer antibodies
  • Maternally-derived antibodies in colostrum
  • Antiserum (artificial)

• Immediate protection

• Short duration of action

Active Immunisation - Copyright nabrown RVC

Active immunisation

• Administer antigen so the patient's own antibodies protect against disease
  • Living organisms
  • Dead organisms
  • Toxoids
  • Subunit antigens
  • DNA

• Delay in protection

• Often needs two or more doses

• Long duration of action

What antigen(s) do we use in the vaccine?

Whole Organsim

• Live attenuated organism
  • Virulent organisms cannot be used as vaccines as they would cause disease
  • Virulence is reduced by growing the organism in altered conditions so that it is less able to replicate when introduced to the host and therefore less likely to cause disease

• Killed inactivated organism or toxin (toxoid)
  • Virulent and toxic organisms cannot be used as vaccines as they would cause disease
  • Organisms can be killed using radiation or chemicals so that they still posess the antigens to stimulate an immune response, but the organisms are unable to replicate inside the host
  • Toxins are inactivated to produce a toxoid which will still have the antigens needed to produce an immune reponse but will not be harmful to the host
  • Needs two doses

Subunit Vaccine (part of the organism)

• Purified protein
  • From lysed organisms

• Recombinant or synthetic protein
  • The gene for the antigen required is inserted into a virus vector or cloned into bacteria
  • Small antigens, such as peptides can be synthetically produced

• DNA coding for proteins (antigens)
  • Can be vaccinated directly into the host

Creators

Natalie Brown

BACK TO IMMUNOLOGY BACK TO HOST INVASION BY MICROORGANISMS