2.9 Therapy of microbial infection

Question 1

What are bacteriophages

Answer 1

Bacteriohpages are bacterial viruses which only target bacteria and are harmless to humans, animals and plants

Question 2

Describe the steps involved in bacteriophage therapy

Answer 2

The bacteriophage which is active against the target bacteria is identified by using bacteria isolated from the patient.
Once a strain of bacteriophage which destroys the bacterium is identified, the bacteriophage can be cultured and introduced into the patients body by oral ingestion, suppository or injection.
The bacteriophage is allowed to attack the bacteria.

Question 3

What are the advantages of bacteriophage therapy

Answer 3

Doesnt affect host cells.
Is specific to bacterial target.
Low side effects.
Rapid production

Question 4

What are disadvantages of bacteriophaeg therapy

Answer 4

Can be difficult to deliver to the site of infection.
Can induce resistance in the target bacteria
Lack of scientific study

Question 5

Name the vaccine types covered

Answer 5

Inactivated
Live attenuated
mRNA
subunit 
viral vector 
toxoid

Question 6

Describe viral vector vaccines

Answer 6

A gene encoding a surface protein (antigen) is cloned and expressed in a non-pathogenic virus strain.
The virus is then grown in cells in vitro and introduced into the host
Host cell expresses viral protein (antigen) on its surface resulting in an immune response

Question 7

What are the probelms associated with traditional vaccines

Answer 7

difficult to obtain sufficient antigen to stimulate a
response if the organism cannot be grown in culture

killed microorganisms do not always produce a good immune response as they do not replicate

Question 8

Describe DNA vaccines

Answer 8

A plasmid encoding an antigen protein is directly injected into host tissue
The host cells take up the vector and express the protein continuously
Protein is available for presentation to immune cells which produce antibodies and cytotoxic T-cells against the pathogen