10th Page Flashcards
What is an immunogen?
A substance capable of triggering an adaptive immune response by inducing formation of antibodies or sensitized T cells.
Immunogens are typically proteins with a molecular weight (MW) that is immunogenic.
What is an antigen?
A substance that can combine with an antibody but may or may not invoke an immune response.
Antigens can be non-protein and are classified as antigenic.
Increase MW, protein, immunogenic
Immunogen
Decrease MW, protein, immunogenic
Antigen
Relationship of host to immunogenic
The more different an antigen is from the host, the more immunogenic it is.
What are the categories of antigens in relation to the host?
- Autoantigen:
- Alloantigen
- Heterologous antigen
- Heterophile antigen
Autoantigen
same individual
different individual, same species
Alloantigen
Relationship of size to immunogenic
The greater the size, the more immunogenic.
Ag in unrelated plants/animals but cross-reacting with other Abs
Heterophile antigen
different individual, different species
Heterologous antigen
Size requirement for immunogenicity?
The molecular weight (MW) should be at least 10,000 daltons
second most immunogenic (less immunogenic than proteins)
Carbohydrates
least or non-immunogenic alone
Lipids and nucleic acids
What is an epitope?
An epitope is a specific part of an antigen that is recognized by the immune system.
What is an epitope?
Part of an antigen/immunogen that binds to the paratope of the antibody.
What is a paratope?
Part of an antibody that binds to the antigenic determinant site
What are the types of epitopes?
The types of epitopes are linear and conformational.
What is a linear epitope?
consists of sequential amino acids on a single polypeptide chain.
What is a conformational epitope?
result from folding a polypeptide chain or chains, bringing non-sequential amino acids into close proximity.
What is a hapten?
A hapten is a nonimmunogenic material that, when combined with a carrier, creates new antigenic determinants.