Vaccines in Theory and Practice
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- Vaccines contain weakened or killed parts of bacteria and viruses to stimulate the immune system and prevent infectious diseases from spreading. The goal is to induce immunity against potential future infections. - Different types of vaccines include live attenuated, inactivated, subunit, toxoid, and conjugate vaccines. They work by exposing the body to antigens in a way that triggers protective antibodies and memory immune cells. - Vaccines are administered via injection or mucosal surfaces to induce both systemic immunity and local immune responses where pathogens enter the body. This interrupts disease transmission and prevents infections.
Vaccines in Theory and Practice
- 1. Vaccines in Theory and Practice Ecz.isa BADUR İmmunoloji
- 5. SUMMARY • Vaccines are necessary to prevent person-to-person transmission of infectious diseases. • Vaccines contain virulence factors from bacteria and viruses. • Vaccines stimulate systemic or mucosal immunity.
- 6. SUMMARY • • Killed, attenuated, subunit, conjugate, and reassortment • vaccines are licensed in the United States. • • Adjuvants are added to vaccines to enhance the immune • response to microbial and viral virulence factors. • • Additives or excipients such as antibiotics, egg protein, • monosodium glutamate, gelatin, and latex are found in • vaccines.
- 7. KEY TERMS • Adjuvant • Attenuation • Endotoxin • Enterotoxin • Exotoxin • Fimbriae • Freund’s adjuvant • Liposomes • Oligonucleotide • Pili • Squalene • Toxoids • Vaccine
- 8. INTRODUCTION Vaccination began with Lady Mary Wortley Montagu, the wife of the English Ambassador to Turkey. In 1723, she popularized the Turkish practice of variolation, in which small amounts of dried smallpox were scratched into the skin of healthy people.
- 9. VARUS,VACCA, VACCINATION In fact, the term variola comes from the Latin word varus, meaning “mark on the skin.” Variolation proved to be protective against smallpox infection. In 1796, Edward Jenner heard stories that dairymaids were immune to smallpox if they had previously been infected with cowpox. Jenner showed that infections with cowpox provided protection from smallpox and that cowpox could be transmitted from dairymaid to dairymaid as a deliberate protection mechanism. Using the Latin word vacca, meaning “cow,” Jenner coined the name for the new procedure vaccination
- 10. VACCA Latin word vacca, meaning “cow,”
- 11. variolation
- 12. VIRULENCE FACTORS include molecules that allow bacterial attachment to mammalian cells such as bacterial pili and fimbriae; polysaccharide capsules that surround pneumococcus and Pseudomonas and prevent phagocytosis; and toxins produced or released from gram-positive and gram-negative bacteria, respectively
- 13. Pili, fimriae
- 16. Three types of toxins are produced by bacteria: • (1) Exotoxins • (2) Endotoxins • (3) Enterotoxins
- 17. Three types of toxins are produced by bacteria: • (1) Exotoxins • are proteins synthesized and secreted by gram-positive • bacteria. Exotoxins destroy mammalian cells or disrupt cellular • function. For example, diphtheria toxin inhibits ribosome • function and protein translation in mammalian cells, • which ultimately kills the cells. Tetanus toxin accelerates the • production of neurotransmitters that promote muscle contraction • in the face (lockjaw) or in the long muscles in the • back (opistothenosis).
- 18. • (2) Endotoxins are lipopolysaccharide • components of the gram-negative cell wall. They consist of • a long antigenic polysaccharide and a lipid A fragment that • interacts with mammalian cells and contributes to septic • or endotoxic shock. Unlike exotoxins, endotoxins are only • released on the death of the bacteria.
- 19. • (3) Enterotoxins are secreted molecules that cause food poisoning and diarrhea. Staphylococcal, cholera, and clostridia enterotoxins produce transient effects in humans. Escherichia coli O157:H7 produces a potent enterotoxin that causes severe diarrhea, dehydration, and death.
- 20. Vaccines are administered • by subcutaneous, intramuscular, or mucosal routes. • Administration by the intramuscular or subcutaneous route stimulates systemic immunity in the spleen, lymph nodes, and peripheral blood.
- 21. prevent the spread • The vaccines interrupt person-to-person transmission and prevent the spread of infectious agents to the critical organs in the body.
- 22. local immune • Mucosal vaccines stimulate local immune responses to microbes at the point of entry into the body.
- 23. ROUTE OF ADMINISTRATION AND MUCOSAL IMMUNITY • The route of administration determines which mucosal surface • is stimulated by microbial agents.
- 24. Oral administration • induces antibody responses in the small intestine, ascending • colon, and mammary and salivary glands.
- 25. nasal administration • protects the upper airways and the lungs but has no effect on the lymphoid tissue in the gut
- 26. TYPES OF VACCINES • • Live, attenuated vaccines • • Inactivated vaccines • • Subunit vaccines • • Toxoid vaccines • • Conjugate vaccines • • Recombinant vector vaccines • • Virosomes • • Plant vaccines
- 29. Live Attenuated Vaccines • Before a live organism can be used in a vaccine, it must undergo a process known as attenuation, which reduces virulence while maintaining immunogenicity. ,
- 30. attenue
- 31. the classic attenuation • process, microbes are passed through unnatural hosts grown on unusual media, or exposed to harsh chemicals for extended periods. As a consequence, microbes usually lose the critical genes necessary to produce virulence factors.
- 32. rationale attenuation inactivates • Removes virulence genes by targeted mutation or gene deletion. Because of their small genome, viruses are relatively easy to attenuate.
- 33. The Sabin polio
- 35. measles
- 36. rubella
- 37. vaccines contain live attenuated viruses. • chickenpox, • herpes zoster, • and hepatitis A
- 38. difficult to attenuate • Bacteria, which have a larger genome, are more difficult to attenuate.
- 39. Only three bacteria • have been attenuated and used in vaccines. • Live attenuated vaccines for typhoid fever and cholera are used in some parts of the world. • Attenuated Mycobacterium bovis, known as Bacille Calmette-Guérin (BCG), is used as a vaccine in Europe and other countries.
- 40. In veterinary medicine • a live attenuated Bacillus anthracis Sterne strain is used to vaccinate cows and horses against anthrax.
- 41. Advantage vs disadvantages • The use of live attenuated vaccines has advantages as well as disadvantages. • A major is that the body does not differentiate between an attenuated microbe and a wildtype microbe, and both elicit a vigorous, long-lasting immune response. • Moreover, only one immunization is required for lasting protection.
- 42. Inactivated Vaccines • Inactivated vaccines consist of organisms killed by physical or chemical means. Killed bacteria are advantageous because they do not revert to the virulent state and pose little health risk to immunosuppressed subjects. • However, they have several disadvantages. When administered intramuscularly, subcutaneously, or by both routes, inactivated vaccines are only weakly immunogenic and often require booster immunizations to achieve lasting protection.
- 43. vaccines contain inactivated viruses. • The Salk polio • and some seasonal influenza
- 44. Subunit Vaccines • Whole-cell vaccines often contain nonantigenic molecules that can cause rare systemic and frequent local adverse health effects. Toxicity is reduced by eliminating all nonantigenic molecules while retaining the antigenic molecules or critical epitopes that are necessary for protection against infection..
- 45. diphtheria–pertussis–tetanus (DPT) • the pertussis component of the diphtheria–pertussis–tetanus (DPT) vaccine comprises inactivated pertussis toxin, purifiedfilamentous hemagglutinin, fimbriae, and pertactin. • Subunit vaccines are advantageous because they do not cause infections and pose little risk to immunosuppressed individuals
- 52. . Diphtheria and tetanus • Antibodies directed at the toxoid neutralize exotoxins before they reach the target cell. Diphtheria and tetanus vaccines contain toxoids which stimulate an immune response.
- 56. Rotavirus strain
- 70. EXCIPIENTS IN VACCINES • Excipients found in vaccines include • antibiotics, • Egg protein, • monosodium glutamate, • gelatin, • yeast, • and latex.