Summary Prevention 2 - Vaccination and prevention of infectous disease

-
11 Flashcards & Notes
1 Students
  • This summary

  • +380.000 other summaries

  • A unique study tool

  • A rehearsal system for this summary

  • Studycoaching with videos

Remember faster, study better. Scientifically proven.

Summary - Prevention 2 - Vaccination and prevention of infectous disease

  • 2 Vaccination versus passive immunization

  • Vaccination is ‘ACTIVE’ immunization  

    Jenner injected infectious material. This is active immunization.

    The body must compose its own immune response. 

     

    Effect: long-term immunity 

     

     

    ‘PASSIVE’ immunization 

    Another possibility to get temporary protection is injection of

    specific antibodies against a particular pathogen. This is a passive

    mode of immunization. The body does not make an immune response. 

     

     The antibodies originate from persons or animals that had a prior

    immune response against the infectious organism. 

     

    Effect: short-term immunity (dependent on antibody half-life) 

  • When passive immunization?

    • therapeutic/post-exposure (rapid effect required; ex. snake bite)
    • prophylactic (to be prepared for an infection; ex. hepatitis A, tetanus)
  • 3 Features of effective vaccines

    • SAFE - V must not itself cause illness
    • PROTECTIVE - must protect against illness resulting from exposure to live pathogen
    • GIVES SUSTAINED PROTECTION - protection against illness must last for several years
    • INDUCES NEUTRALIZING ANTIBODY - Some pathogens infect cells that can't be replaced. Neutralizing antibody is essential to prevent the infection of such cells.
    • INDUCES PROTECTIVE T-CELLS - some pathogens, particularly intracellular, are more effectively dealt with by cell-mediated responses
    • PRACTICAL CONCIDERATIONS - low cost per dose, biological stability, ease of administration, few side-effects
  • 4 Live and Dead vaccines

  • Live and Dead vaccines

    Live vaccines - live attenuated

    For human non-virulent or attenuated/weakened microorganisms: 

    • Animal microorganisms (e.g. cow-pox)
    • Human cultured and thereby changed microorganisms 

     

    Dead vaccines 

    • Killed, but intact microorganisms = COMPLETE MICROORGANISM
    • Inactivated toxins of microorganisms (toxoid) = TOXOID VACCINES
    • Antigenic structures of microorganisms = SUBUNIT VACCINES


    Subunit vaccines may lack appropriate immunogenicity; they don't raise a full blown antibody response.

    ==> SOLUTION: CONJUGATED VACCINES

     

    Conjugated vaccines

    The subunit antigen is coupled to a carrier-peptide that induces a supporting T helper cell response.

     

    Effective in younger children, longer immunity and memory responses, more effective protection;

     

     

  • 5 Adjuvants

  • Addition of adjuvants to a vaccine is essential for succesful vaccination.

  • Function of adjuvants?

    • Bind and complex the antigen to increase antigen presentation  (AL-hydroxide)
    • Provide local storage (oil)
    • Induce an inflammatory reaction (bacterial substances, cytokines) 
  • 6 Safety of vaccines

  • Potential problems of vaccines

  • 7 Certain vaccines are not effective

  • Causes:

    • induced effector mechanism is inappropriate
    • a too high risk for disease
    • vaccination does not provide immunity due to antigenic variation of the microorganism
  • 8 Research in vaccination of infectious disease

  • Improvement of antigen administration

    • recombinant live vaccines: weakened viral and bacterial vectors for expression of vaccine genes --> enhances tissue-specific immunisation
    • DNA vaccination: plasmid vectors for administration and expression of vaccine genes (or cDNA) through intramuscular injection
  • Improvement of adjuvants for adequate antigen uptake and priming of the immune response

    Packaging of antigenic peptides in liposomes --> better uptake and loading in MHC 1

  • Current research in vaccination of infectious  diseases aims at strategies for programming T-cell responses by triggering innate immunity.

Read the full summary
This summary. +380.000 other summaries. A unique study tool. A rehearsal system for this summary. Studycoaching with videos.