Practical Applications of Immunology |
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Vaccines
A vaccine is a substance that when injected causes the production of specific antibodies.
Edward Jenner developed the modern practice of vaccination when he inoculated people with cowpox virus to protect them against small pox. (hmmm…)
Principles And Effects Of Vaccination
Herd immunity results when most of a population is immune to a disease.
Sabin (OPV) and Salk (IPV) Polio Vaccines
Sabin (OPV)Attenuated virus
Three strains of the poliovirus
Promotes cell mediated immunity
Administration
- Only one
- Oral
- Can be adminsitered by unskilled personnel
It can, however, revert and cause the disease...
Salk (IPV) Inactivated virus
Very safe
Cannot cause the disease
Promotes humoral immunity only
Required boosters
Types Of Vaccines And Their Characteristics
Attenuated whole-agent vaccines consist of attenuated (weakened) microorganisms: attenuated virus vaccines generally provide lifelong immunity.
Measles, mumps, rubella, chickenpox, the Sabin polio vaccine, typhoid vaccines, and the BCG vaccine are examples.
Inactivated whole-agent vaccines consist of killed bacteria or viruses.
Rabies, influenza, cholera, and the Salk polio vaccine are inactivated whole agents.
Toxoids are inactivated toxins.
Examples include tetanus and diphtheria toxoids.
Subunit vaccines consist of antigenic fragments of a microorganism; these include recombinant vaccines and acellular vaccines.
Hepatitis B and the acellular pertusis vaccine are examples.
Conjugated vaccines combine the desired antigen with a protein that boosts the immune response.
Examples include the Hib, pneumococcal, and meningococcal vaccines
Nucleic acid vaccines, or DNA vaccines, are being developed. These cause the recipient to make the antigenic protein associated with class I MHC (HLA).
Routes of Administration
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Subcutaneous
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Intramuscular
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Intradermal
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Oral
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Intranasal
The Development Of New Vaccines
Viruses for vaccines may be grown in animals, cell cultures, or chick embryos.
Recombinant vaccines and nucleic acid vaccines do not need to be grown in cells or animals.
Genetically engineered plants may someday provide edible vaccines.
Adjuvants improve the effectiveness of some antigens.
Safety Of Vaccines
Vaccines are the safest and most effective means of controlling infectious diseases.
Complications of Vaccines
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Problems in administration
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Administration to pregnant women
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Infection
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Local reactions at the injection site
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Fever
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Allergies
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Development of disease
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Mutation to a virulent strain