Difference between revisions of "Vaccines"
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| Line 48: | Line 48: | ||
*Long duration of action | *Long duration of action | ||
| − | ==What | + | ==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 | ||
==Links== | ==Links== | ||
Revision as of 16:24, 25 August 2008
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
- Administer antibodies
- Maternally-derived antibodies in colostrum
- Antiserum (artificial)
- Immediate protection
- Short duration of action
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