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| 1:4000 formaldehyde is used in the preparation of killed vaccines; inactivants containing azuridines and beta propiolactone are being developed which do not leave a persistent infectious viral fraction (like formaldehyde). | | 1:4000 formaldehyde is used in the preparation of killed vaccines; inactivants containing azuridines and beta propiolactone are being developed which do not leave a persistent infectious viral fraction (like formaldehyde). |
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− | ===Subunit Vaccine (part of the organism)=== | + | ===Subunits (part of the organism)=== |
| + | These can be purified proteins such as a single envelope protein separated from a purified virus by detergent and then centrifuged (traditional method) - genetic engineering can now make single protein vaccines quickly and accurately. |
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− | *Purified protein
| + | Recombinant or synthetic protein can also be used as a subunit - the gene for the antigen required is inserted into a virus vector or cloned into bacteria allowing endogenous expression of the antigen. Small antigens, such as peptides, can be produced synthetically where necessary e.g. with |
− | **Single envelope protein separated from a purified virus by detergent then centrifuged (traditional method)
| + | Influenza viruses that are constantly mutating, and Canary pox vaccines encoding rabies or FeLV spike proteins (canary pox is safe as it undergoes incomplete replication in mammalian skin cells). |
− | **Genetic engineering can now make single protein vaccines
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− | *Recombinant or synthetic protein
| + | Subunit antigens can also be isolated using the DNA coding for antigenic proteins; circular DNA plasmids are expanded in disabled E.coli strains and then purified - the plasmids expressing the foreign gene are inserted at the site of injection which can be vaccinated directly into the host. |
− | **The gene for the antigen required is inserted into a virus vector or cloned into bacteria allowing endogenous expression
| |
− | **Small antigens, such as peptides, can be synthetically produced
| |
− | **E.g. Being developed constantly to fight the Influenza viruses
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− | **E.g. Canary pox vaccines encoding rabies or FeLV spike proteins (canary pox is safe as it undergoes incomplete replication in mammalian skin cells)
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− | | |
− | *DNA coding for proteins (antigens)
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− | **Circular DNA plasmids expanded in disabled E.coli strains and then purified
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− | **Plasmids express the foreign gene insert at the site of injection
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− | **Can be vaccinated directly into the host
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| ===Adjuvants=== | | ===Adjuvants=== |