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'''Disadvantages:'''
'''Disadvantages:'''
*Short duration of action
*Short duration of action
**Temporary protection by the administration of preformed antibody from another individual of the same or of a different species
**Temporary protection by the administration of preformed [[Immunoglobulins - WikiBlood|antibody]] from another individual of the same or of a different species
**The aquired antibodies are used in combination with antigen and catabolised by the body meaning protection is gradually lost
**The aquired [[Immunoglobulins - WikiBlood|antibodies]] are used in combination with [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] and catabolised by the body meaning protection is gradually lost
*Injection of antiserum may cause an allergic response
*Injection of antiserum may cause an [[Allergic diseases - WikiClinical|allergic response]]
*Antiserum contains many antibodies not just the specific antobodies needed
*Antiserum contains many [[Immunoglobulins - WikiBlood|antibodies]] not just the specific [[Immunoglobulins - WikiBlood|antibodies]] needed
'''Types of antibodies administered:'''
'''Types of [[Immunoglobulins - WikiBlood|antibodies]] administered:'''
*Maternally-derived antibodies in colostrum
*Maternally-derived [[Immunoglobulins - WikiBlood|antibodies]] in [[Materno-fetal immunity - WikiBlood#Passive transfer via colostrum|colostrum]]
*Antiserum (artificial)
*Antiserum (artificial)
**The antigen (and often an adjuvant) is injected into the host animal
**The [[Immunoglobulins - WikiBlood|antibodies]] are used in combination with [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] (and often an [[Vaccines - WikiBlood#Adjuvants|adjuvant]]) is injected into the host animal
**The immune system of that animal synthesised antibodies
**The immune system of that animal synthesised [[Immunoglobulins - WikiBlood|antibodies]]
**Repeated injections at intervals increases the total antibody production
**Repeated injections at intervals increases the total [[Immunoglobulins - WikiBlood|antibody]] production
**The immunised animal is bled and the serum collected which contains the newly made antibodies. The serum is called '''antiserum'''.
**The immunised animal is bled and the serum collected which contains the newly made [[Immunoglobulins - WikiBlood|antibodies]]. The serum is called '''antiserum'''.
**The serum can then be injected into a different animal to confer passive immunisation
**The serum can then be injected into a different animal to confer passive immunisation
[[Image:Active Immunisation.jpg|thumb|right|150px|Active Immunisation - Copyright nabrown RVC]]
[[Image:Active Immunisation.jpg|thumb|right|150px|Active Immunisation - Copyright nabrown RVC]]
===Active immunisation===
===Active immunisation===
*Administer antigen so the patient develops its own antibodies to protect against disease
*Administer [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] so the patient develops its own [[Immunoglobulins - WikiBlood|antibodies]] to protect against disease
**Living organisms
**Living organisms
**Dead organisms
**Dead organisms
'''Advantages'''
'''Advantages'''
*Long duration of action
*Long duration of action
**Once antibody is produced against the antigen, memory cells are formed which continue circulating in the body
**Once [[Immunoglobulins - WikiBlood|antibody]] is produced against the [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]], [[B cell differentiation - WikiBlood#Memory cells|memory cells]] are formed which continue circulating in the body
**For further information on memory cells click [[B cell differentiation - WikiBlood|here]]
**For further information on memory cells click [[B cell differentiation - WikiBlood|here]]
'''Disadvantages'''
'''Disadvantages'''
*Delay in protection
*Delay in protection
**The host's immune system needs to evoke an immune response against the antigen which can take a few days
**The host's immune system needs to evoke an immune response against the [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] which can take a few days
**For further information on the antibody response click [[Adaptive Immune System - WikiBlood|here]]
**For further information on the [[Immunoglobulins - WikiBlood|antibody]] response click [[Adaptive Immune System - WikiBlood|here]]
*Often needs two or more doses
*Often needs two or more doses
**The first dose initiates the '''priming''' reaction where antibody production ceases after a few weeks, but the second and subsequent doses creates memory cells which remain in the circulation for a much longer period of time
**The first dose initiates the '''priming''' reaction where [[Immunoglobulins - WikiBlood|antibody]] production ceases after a few weeks, but the second and subsequent doses creates [[B cell differentiation - WikiBlood#Memory cells|memory cells]] which remain in the circulation for a much longer period of time
**For further information on the T cell independent and dependent responses click [[B cell differentiation - WikiBlood#T-Cell Dependent and Independent Responses|here]]
**For further information on the T cell independent and dependent responses click [[B cell differentiation - WikiBlood#T-Cell Dependent and Independent Responses|here]]
**Virulent organisms cannot be used as vaccines as they would cause disease
**Virulent organisms cannot be used as vaccines as they would cause disease
**Virulence is reduced by growing the organism in altered conditions so that it is less able to replicate when introduced to the host and therefore less likely to cause disease
**Virulence is reduced by growing the organism in altered conditions so that it is less able to replicate when introduced to the host and therefore less likely to cause disease
**Produces a superior response to disease than using killed organisms as the dose of antigen is larger and more sustained
**Produces a superior response to disease than using killed organisms as the dose of [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] is larger and more sustained
**Response takes place at site of natural infection producing a greater local response than with killed organism vaccines
**Response takes place at site of natural infection producing a greater local response than with killed organism vaccines
**E.g. The current vaccine for Tuberculosis (called BCG) contains an attenuated form of a mycobacteria
**E.g. The current vaccine for Tuberculosis (called BCG) contains an attenuated form of a mycobacteria
*Killed inactivated organism or toxin (toxoid)
*Killed inactivated organism or toxin (toxoid)
**Virulent and toxic organisms cannot be used as vaccines as they would cause disease
**Virulent and toxic organisms cannot be used as vaccines as they would cause disease
**Organisms can be killed using radiation or chemicals so that they still possess the antigens to stimulate an immune response, but the organisms are unable to replicate inside the host
**Organisms can be killed using radiation or chemicals so that they still possess the [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigens]] to stimulate an immune response, but the organisms are unable to replicate inside the host
**Toxins are inactivated to produce a toxoid which will still have the antigens needed to produce an immune response but will not be harmful to the host
**Toxins are inactivated to produce a toxoid which will still have the [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigens]] needed to produce an immune response but will not be harmful to the host
**Needs two doses (for an explanation on the T cell responses click [[B cell differentiation - WikiBlood#T-Cell Dependent and Independent Responses|here]])
**Needs two doses (for an explanation on the [[Lymphocytes - WikiBlood#T cells|T cell]] response click [[B cell differentiation - WikiBlood#T-Cell Dependent and Independent Responses|here]])
===Subunit Vaccine (part of the organism)===
===Subunit Vaccine (part of the organism)===
*Recombinant or synthetic protein
*Recombinant or synthetic protein
**The gene for the antigen required is inserted into a virus vector or cloned into bacteria
**The gene for the [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] required is inserted into a virus vector or cloned into bacteria
**Small antigens, such as peptides can be synthetically produced
**Small [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigens]], such as peptides can be synthetically produced
**E.g. being developed constantly to fight the Inflenza viruses
**E.g. being developed constantly to fight the Inflenza viruses
*DNA coding for proteins (antigens)
*DNA coding for proteins ([[Adaptive Immune System - WikiBlood#Antigen Recognition|antigens]])
**Can be vaccinated directly into the host
**Can be vaccinated directly into the host
*Used with vaccines containing inactivated organisms which alone only stimulate a weak immune response
*Used with vaccines containing inactivated organisms which alone only stimulate a weak immune response
*Some create a depot of antigen at the injection site allowing a steady flow of antigen into the afferent lymph
*Some create a depot of [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] at the injection site allowing a steady flow of [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] into the afferent lymph
*Some stimulate the immune system to amplify the adaptive immune response to antigens
*Some stimulate the immune system to amplify the adaptive immune response to [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigens]]
**E.g. Pathogen-associated molecular patterns (PAMPs)
**E.g. Pathogen-associated molecular patterns (PAMPs)
**E.g. PAMP-like adjuvants which assist naive T cell priming
**E.g. PAMP-like adjuvants which assist naive [[Lymphocytes - WikiBlood#T cells|T cell]] priming
*Different subtypes of T helper cells are stimulated by different adjuvants
*Different subtypes of [[Lymphocytes - WikiBlood#Helper CD4+|T helper cells]] are stimulated by different adjuvants
**E.g. Aluminium salts generate bias T helper II responses for '''antibody'''-mediated immunity
**E.g. Aluminium salts generate bias [[T cell differentiation - WikiBlood#TH2 Cells|T helper II]] responses for [[Immunoglobulins - WikiBlood|'''antibody''']]-mediated immunity
**E.g. Killed mycobacteria generate IL-12 producing good '''cell'''-mediated immunity
**E.g. Killed mycobacteria generate IL-12 producing good '''cell'''-mediated immunity
*Adjuvants decrease the number of injection needed and the amount of antigen administered
*Adjuvants decrease the number of injection needed and the amount of [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigen]] administered
==Which type of vaccine is used for each disease?==
==Which type of vaccine is used for each disease?==
*The virus life cycle consists of an extracellular phase, a replicative intracellular phase and another extracellular phase spreading viral particles to other cells to begin the life cycle again
*The virus life cycle consists of an extracellular phase, a replicative intracellular phase and another extracellular phase spreading viral particles to other cells to begin the life cycle again
*Immunity for the extracellular phase requires neutralising '''antibody'''
*Immunity for the extracellular phase requires neutralising [[Immunoglobulins - WikiBlood|'''antibody''']]
**B cells needed
**[[Lymphocytes - WikiBlood#B Cells|B cells]] needed
**T helper type II cells needed (for the MHC class II pathway)
**[[T cell differentiation - WikiBlood#TH2 Cells|T helper type II cells]] needed (for the [[MHC - WikiBlood#MHC II|MHC class II pathway]])
**Live vaccine can be used
**Live vaccine can be used
**Killed vaccine can be used
**Killed vaccine can be used
**Subunit vaccine can be used
**Subunit vaccine can be used
*Immunity for the intracellular phase requires '''CD8+ cytotoxic T cells'''
*Immunity for the intracellular phase requires [[Lymphocytes - WikiBlood#Cytotoxic CD8+|'''CD8+ cytotoxic T cells''']]
**MHC class I pathway
**[[MHC - WikiBlood#MHC I|MHC class I pathway]]
**Only live vaccine can be used to get into cells (entering via the endogenous pathway)
**Only live vaccine can be used to get into cells (entering via the endogenous pathway)
===Immunity to Bacterial Infection===
===Immunity to Bacterial Infection===
*Extracellular bacterial infection need '''antibody''' production for opsonisation and to activate the complement pathways
*Extracellular bacterial infection need [[Immunoglobulins - WikiBlood|'''antibody''']] production for [[Complement - WikiBlood#Opsonisation|opsonisation]] and to activate the [[Complement - WikiBlood|complement pathways]]
**B cells needed
**[[Lymphocytes - WikiBlood#B Cells|B cells]] needed
**T helper type II cells needed
**[[T cell differentiation - WikiBlood#TH2 Cells|T helper type II cells]] needed
*Vesicular infections can only be cured by organisms being destroyed inside '''macrophages'''
*Vesicular infections can only be cured by organisms being destroyed inside [[Macrophages - WikiBlood|'''macrophages''']]
**T helper type I cells needed
**[[T cell differentiation - WikiBlood#TH1 Cells|T helper type I cells]] needed
==When do we vaccinate?==
==When do we vaccinate?==
*Usually when animals are young
*Usually when animals are young
*Breeding females so immunity is passed to offspring via the colostrum
*Breeding females so immunity is passed to offspring via the [[Materno-fetal immunity - WikiBloodPassive transfer via colostrum|colostrum]]
**Protects neonates for the first 8-12 weeks of life
**Protects neonates for the first 8-12 weeks of life
*Vaccination of young animals should be when the natural passive immunity decreases below the threshold for providing protection. Active immunity should then be stimulated so that the animal has constant protection. The vaccination should not be given too early, as the natural immunity can interfere with immunisation by binding and neutralising the vaccine antigens.
*Vaccination of young animals should be when the natural passive immunity decreases below the threshold for providing protection. Active immunity should then be stimulated so that the animal has constant protection. The vaccination should not be given too early, as the natural immunity can interfere with immunisation by binding and neutralising the vaccine [[Adaptive Immune System - WikiBlood#Antigen Recognition|antigens]].
*2 vaccines are usually given to allow for differences between neonates as the point where natural immunity decreases and active immunity needs to be stimulated, will differ between littermates and between different animals
*2 vaccines are usually given to allow for differences between neonates as the point where natural immunity decreases and active immunity needs to be stimulated, will differ between littermates and between different animals