Antigens Flashcards
Why are bacterial antigens considered as virulence factors?
They can resist eradication by the immune system and cause disease. E.g. A bacterium that possesses a capsule is greatly resistant to ingestion by phagocytic cells.
Name a bacteria which is resistant to ingestion by phagocytic cells.
Streptococcus pneumonia.
How can you identify streptococcus pneumonia?
By its capsular surface made up of polysaccharide antigen.
What bacteria structure is associated with the K antigen?
Capsule
What bacteria structure is associated with the H antigen?
Flagellum.
What bacteria structure is associated with the O antigen?
Cell wall.
What part of the virus can act as the antigen?
Viruses are so small, that the capsid portion (surrounding the genome) can act as an antigen.
What can make virus give a good immune response or a bad one?
Many times virus’ capsid is composed of lipoproteins so a virus can stimulate a potent immune response.
But since they are small they can evade the immune system all together and that prevents their capsid from being recognized.
What are red blood cells antigens made up of?
Oligosaccharide chains attached to the surface of the cell by a protein or lipid molecule.
How early are the ABO blood group antigens detectable in human blood?
As early as 5 weeks of fetal life.
What dictates what blood group a person has?
The type of antigen (A, B, both or neither) on a persons RBCs.
How many people of the A antigen?
42%
How many people have the B antigen?
10%
How many people have the A and B antigens (i.e. type AB blood)?
3%
How many people have neither A or B antigens (i.e. type O blood)?
45%
