Passive Immunisation
– Antibodies transferred from another person or animal
(natural maternal antibodies, antitoxins, and immune globulins)
Protection is temporary
Active Immunisation
- Development of own immune response via natural infection or vaccination
Protection is relatively permanent - Both stimulate the proliferation of T and B cells, resulting in the
formation of effector and memory cells - The formation of memory cells is the basis for the relatively permanent
effects of vaccinations
disadvantages of passive immunisation
▪ The transfer of antibodies will not trigger the immune system
▪ There is NO presence of memory cells
▪ Risks:
-Some individuals produce IgG or IgM molecules specific for passive antibody,
leading to hypersensitive reactions (e.g. mast cell degranulation)
Types of vaccines
▪ Whole-Organism
– Attenuated Viral/Bacterial
– Inactivated Viral/Bacterial
▪ Purified Macromolecules
– Polysaccharide
– Toxoid (toxin rendered inactive)
– Recombinant Antigen
– Recombinant-Vector
▪ Nucleic acids (DNA, RNA)
▪ Synthetic Peptide
Adjuvents
- Substances that enhance the immunogenicity of antigens
(presumably by modulation of dendritic cells to become optimally stimulatory to T
cells) - Found empirically
features of successful vaccine
- must be able to produce protective immunity in a very high proportion of the people
to whom it is given - must generate long lived immunological memory (must prime both B and T
lymphocytes). - must be safe (even a low level of toxicity is unacceptable)
- must be very cheap if they are to be administered to large populations
Jenner - 1796 and Pasteur - 1880s
- demonstrated that inoculation with cowpox could protect against smallpox
- Cowpox virus contains antigens that cross-reacts with
smallpox antigens and stimulate the immune response
thereby conferring protection against the human disease
In the 1880s, Louis Pasteur devised vaccines against
cholera in chickens, anthrax and rabies
