Lecture 1: Introduction to infection and immunity Flashcards
What are bacteria?
Small, single celled, prokaryotic organisms, divide by binary fission, may be mobile (flagella).
What are viruses?
Particles of nucleic acid (either DNA or RNA) in a protein coat + / - a lipid capsule. Interact with living cells to replicate.
What are fungi?
Eukaryotic species; includes microorganisms such as yeasts and moulds, as well as the more familiar mushrooms.
What are protozoa?
Huge family of single-celled eukaryotic parasites that are responsible for the major tropical and zoonotic diseases.
What are helminths?
Parasitic worms
Define the term ‘antigen’
Any substance that induces the immune system
What is meant by antigen specificity?
Immune system specifically recognises different antigens. Infection with measles does not appear to protect from infection with mumps.
What is meant by immunological memory?
• The immune system has ‘memory’. Initial immune response is weak until antibodies are produced. Subsequent immune response is different and quicker and less likely to result in disease as antibodies are already present.
What is meant by immune tolerance?
Tolerance is a state of immunological non-reactivity to an antigen and this is important because many antigens that we exposed to are not harmful.
What is an allergy?
An immune system response to a foreign substance that’s not typically harmful to your body; breakdown of tolerance.
What is auto-immunity?
System of aberrant immune responses in an organism against its own healthy cells, tissues and other normal body constituents; breakdown of tolerance and immunity.
What is acquired immunodeficiency?
Immunodeficiency acquired through infection eg. HIV and AIDs
What is genetic immunodeficiency?
Congenital immunodeficiency since birth eg. severe combined immunodeficiency (SCID)
