Immunology Lecture 12 Flashcards
Define serology.
Antibody-antigen reactions in vitro.
Define neutralisation.
Antibody-antigen reaction resulting in a coated antigen, with the chief aim being to prevent entry to cells.
Define precipitation.
Antibody-antigen reaction resulting in a chain complex of antibody bound to antigens, such that they aggregate and fall out of solution.
In a standard precipitation reaction, define the zone of antibody excess, antigen excess, and equivalence.
Antibody excess - no agglutination due to lack of antigen
Antigen excess - no agglutination due to lack of antibody
Equivalence - appropriate amounts of both allow for a chain complex to form, agglutinating.
Do agglutination tests reveal the number of antibodies in the blood?
No, only positive or negative.
What fold increase to antibodies suggests a recent infection?
4-fold.
Define titre in the context of serology.
Used to assess the number of antibodies in blood. Serial dilution of blood is done, followed by antigen addition.
When viruses agglutinates in response to blood, how does it appear vs a normal drop?
A normal drop of blood is dome/convex shaped.
Agglutination will result in a spread out, thin layer of blood.
Hoe can antibody production be assessed? Use influenza as an example.
Blood is obtained, and influenza is added. If agglutination occurs, antibodies are present.
Describe the complement fixation test.
Antigens and complements are added to serum. If antibodies are present, addition of RBC antibodies will not cause haemolysis, as complements have bound to the antibodies if they were present.
Haemolysis therefore suggests the absence of antibodies.
What is a monoclonal antibody? What is generated after an infection?
Antibody derived from a single B cell clone.
Polyclonal serum is generated after an infection, due to the presence of many epitopes and antigens.
How are pure clones of B cells obtained?
Mice injected with an antigen.
Spleen taken, mushed, and mixed with myeloma cells to immortalise B cells.
Streak dilution used to isolate single B cells, identified by adding antigens after culturing.
B cell then propagated.
Can pure clones be used indefinitely?
Typically, but will require testing to ensure no mutations have occurred.
Define ELISA and what the technique relies on.
Enzyme linked immunosorbent assay.
Relies on enzymes attached to antibodies.
Outline the process of direct ELISA.
Microplate coated in an antibody.
Serum is added.
If present, antigen will bind to the primary antibody.
An enzyme linked anti-human antibody is added next - if an antibody is bound to the antigen, the anti-human antibody will bind to it.
Enzyme substrate is added, inducing colour change if they are bound.
