Exam 1: Bacterial Vaccines Flashcards
What are reasons why a vaccine may be highly immunogenic but not protective?
The immune response is not directed at the right antigens
The wrong type of immunity is stimulated
The immune response does not last long enough
What are the types of bacterial vaccines?
Bacterin
Live attenuate vaccine
What is bacterin?
Killed bacterial vaccine by either heat or chemical
What are the advantages to bacterin?
Typically better at stimulating humoral immunity
Generally safe
What are the disadvantages to bacterin?
Immunity may not persist as long as live attenuated vaccines
Immunity is not generate against in vivo expressed antigens
What are the advantages to live attenuated vaccines?
Usually better at generating cell mediated immunity
Can persist longer in the host, generating longer term immunity
Can generate immunity to in vivo expressed antigens
Can be capable of active invasion, depending on the pathogen
What are the disadvantages to live attenuated vaccines?
Risk of reversion or causing clinical signs in an immunocompromised host
There are technical challenges in keeping vaccine strain alive
What are the methods of attenuation?
Selection of naturally attenuate strain
Passage on artificial media (or selection for antibiotic resistance)
Gene mutation
What are the different methods of gene mutation for attenuation?
Virulence gene
Biochemical pathway
Regulatory gene
What are subunit vaccines?
One or more purified antigens from the bacterial pathogen
What can subunit vaccines be?
Protein or polysaccharide
What must the immunity to the antigen be for subunit vaccines?
Protective
What are the advantages of a subunit vaccine similar to?
Those of bacterins
What is a toxoid vaccine?
An inactivated toxin
What are toxoids effective against?
Disease where primary pathology is caused by an exotoxin
