Vaccination and Immunisation Flashcards
What are the essential characteristics of vaccines?
- Must provide effective protection without risk of causing disease or severe side effects.
- Protection should be long-lived.
- Stimulate correct arm of immune response.
- Stimulate neutralising antibodies to prevent re-infection.
- Stable for long-term storage and transport.
- Economically affordable for widespread use
Name the different types of vaccines
Life, Attenuated, killed, extract, recombinant and DNA.
Describe what a live vaccine?
Organisms capable of normal infection and replication. Therefore they cannot be used against pathogens that cause severe disease.
Describe attenuated vaccines
Organism is live but ability to replicate and causes disease is reduces by chemical treatment or growth-adaptation in non-human cell lines.
Describe killed vaccinations
Organism killed by physical or chemical treatment. It is incapable of infection or replication but can still provoke a strong immune response
Describe extract vaccines
Materials derived from disrupted or lysed organism, eg, capsular polysaccharides. These are used when there is a risk of an organism surviving inactivation steps.
Describe recombinant vaccines
Genetically engineered to alter critical genes. Often can infect and replicate but doesn’t induce associated disease
Describe DNA vaccines
Naked DNA injected. Host cells then pick up DNA and express pathogen proteins that stimulate the immune response
What vaccine is best?
Generally the most effective vaccines have been live or attenuated as they stimulate the immune response in a manner which most closely resembles normal infection. Tends to be the more safe the vaccine, the less effective it is.
Describe features of herd immunity
This is the beneficial impact of vaccination which means if enough people are immunised then the chances of an unprotected person meeting a pathogen becomes small.
What is DTaP/IPV/Hib vaccine?
Diptheria, tetanus, pertussis, Inactivated polio vaccine, Haemophilus influenza type B (6 in 1 vaccine)
Men C vaccine?
Meningococcal C conjugate
DTaP/IPV vaccine?
Booster vaccine for diptheria, tetanus, pertussis and polio
Td/IPV vaccine?
Booster vaccine for tetanus, diptheria and polio
Who is offered the pneumococcal vaccine given too?
It is offered to 65years and over individuals
Describe the reverse vaccinology for Meningococcal B
1) Whole bacterial genome is sequences,
2) 600 candidate genes identified.
3) 350 expressed in E.coli bacteria in lab.
4) 344 proteins purified and used to generate antisera in mice
5) 91 novel surface molecules identified
6) 28 bactericidal sera identified
7) 5 vaccine candidates in clinical trials. Total time =24-36 months
What do dendritic cells express and what is their role?
Pattern recognition receptors which are members of the toll-like receptor family. They recognise components of pathogens
What do TLR4 recognise?
Lipopolysaccharides and heat shock proteins.
What is the role of dendritic cells?
They encounter antigens in the periphery and become activated, then migrate to lymph nodes where they activate T cells to become effector cells.
What occurs when CpG is included with HepB or flu vaccines?
It increases antibody or interferon gamma secretion
