14: assisted immunity via vaccination Flashcards
abdul chaundry (19 cards)
what is a vaccine?
a form of pathogen-based material administered to induce long-lived immunological responses against an infection
what has to be considered when developing vaccines?
- efficacy n cost of vaccination
- adding markers to detect if antibodies are produced from current infection or vaccination
how do animals allocate resources under healthy vs diseased conditions?
healthy: 10% health, 30% maintenance, 30% reproduction, 30% growth
diseased: 80% health, 20% maintenance
what is the goal of a vaccination?
inducing B- and T-cell responses, stimulating memory cells in order to wither prevent infection or reduce the severity of disease
how does antibody concentration vary among the primary and secondary infection?
the primary response is slow and requires time to reach a high amount of antibodies, the secondary response is elicited faster and is more intense
what are the features of an effective vaccine?
- safe, not causing ill-effects
- protective
- inducing antibodies
- inducing t-cells
- easy to produce
- easy to administer
why is stimulating mucosal immunity so important?
- it is a major route for pathogen entry into body
- ABs in mucosal secretions trap bac n block virus entry
- mucous clocks adherence of organisms to the epithelial surface n prevent invasion
- blood vessels in sub-mucosa readily supply immune cells if invasion
what are 3 specialised areas of mucosal tissue?
- GALT: gut-associated lymphoid tissue
- BALT: bronchial-associated lymphoid tissue
- MALT: mucosa-associated lymphoid tissue
what are 3 types of vaccines in use?
- killed/inactivated vaccines
- attenuated vaccines
- sub-unit vaccines
what are killed/inactivated vaccines?
whole pathogenic bacteria or viruses that are made non-replicating and non-infectious eg by formalim
what are attenuated vaccines?
live virus articles that are mutated to a non-pathogenic form, usually by rapid passage in tissue culture cells of a foreign host
what are sub-unit vaccines?
purified components of a pathogen, such as viral surface antigen or bacterial toxoid, for example diphtheria, tetanus, botulism
what are 4 examples of vaccines?
- lamb pneumonia: formalin-killed cells from pasteurella haemolytica
- bovine/ovine/porcine enterotoxaemia: - clostridium perfringens toxoid
- avian viral arthritis/tenosynovitis: formalin-inactivated reovirus
- avian infectious bronchitis: live attenuated IB virus
what are advantages and disadvantages of inactivates/killed vaccines?
advantages:
- elicit good humoral immunity
- cannot mutate/revert to pathogenic form
disadvantages:
- require adjuvant formulations
- usually injected
- boosters needed
- poor inducers of mucosal immunity
- high cost
- failure of inactivation may lead to entry of infectious material
what are advantages and disadvantages of live attenuated vaccines?
advantages:
- mimic natural infection, as they elicit systemic and mucosal immunity
- use antigens -> in natural form
- easier and cheaper to produce
- can be given via non-injection routes
disadvantages:
- possible mutation/reversion to virulence
- spread of vaccine strain possible
how can synthetic peptides be used as a vaccine?
- small peptides based on a pathogen’s protein can raise immunoglobulin G response
- often problems w immunogenicity (ability of a substance that contains antigens to cause the body to make an immune response against that substance)
- under research, successful against CSFV
how can recombinant proteins be used as a vaccine?
- whole proteins are cloned n expressed in bacteria/yeast
- effective as a human hepatitis B vaccine and infectious bursal disease virus in poultry
what is a dna vaccine?
- transfects a specific antigen-coding DNA sequence into the cells of an organism as a mechanism to induce an immune response
- injected into muscles/skin via a gene gun made of plasmid-coated gold particles
what are advantages of DNA vaccines?
- versatility: can be produced against many organisms, marker vaccines can be engineered, can be used to screen for protective antigens
- inherent adjuvanticity: bacterial DNA contains CpG motifs which activate macrophages
- immunogenicity: induce humoral n cellular immunity
- cost: cheap to produce, store n administer
- safety - no pathogen culture needed, no reversion to virulence
