Exam 2 (Lecture 10) - Monoclonal Antibodies

Question 1

List the important surface molecules that distinguish T and B cells and describe their function.

Answer 1

1) T cell:
- CD3 (pan T marker); functions in
signal transduction
- CD4 functions to bind MHC II
- CD8 functions to bind MHC I
- TCR (alpha-beta T cells and
gamma-delta T cells)

2) B cell:
- BCR
- CD20
- CD19
- CD21 (using now to identify B cell
lymphoma)

Question 2

Explain how T and B cells are identified.

Answer 2

There are antibodies to the surface molecules (ie CD3) that have fluorescent dye covalently bound to them (flow cytometry).

Question 3

Compare and contrast a primary and secondary antibody response, including the basis for the difference in the lag time, titer, antibody class, and antibody affinity.

Answer 3

1) Primary Antibody Response
- Lag time: 7-14 days
- Titer: Low
- Ab Class: IgM
- Ab affinity: Low

2) Secondary Antibody Response
- Lag time: 2-3 days (shorter
because of memory/clonal
expansion = more lymphocytes
recognize that antigen)
- Titer: High (for same reason as ^)
- Ab Class: IgG, IgE, IgA (don’t get all
of them at the same time; different
responses lead to different Ab)
- Ab affinity: High (mechanisms:
affinity maturation (random
mutations are selected for)

Question 4

Understand why clonal expansion of a lymphocyte population is important for immunity.

Answer 4

Important to have a lot more cells to fight an infection (A LOT more titer more quickly).

Question 5

Define hybridoma and include in your definition the cells that are used to make hybridomas and the purpose of hybridomas.

Answer 5

Hybridomas make large quantities of monoclonal antibodies; hybridoma is a hybrid of a B cell and a myeloma cell (plasma cell tumor) and makes specific antibody (specific to epitope).

Purpose is to use the monoclonal antibodies for therapies (like for cancer) and for diagnostic tests (ie SNAP tests).

Question 6

Define and use in a sentence polyclonal and monoclonal antibody.

Answer 6

1) Monoclonal antibody = antibody that is from one clone (very specific; all Abs are the same).

2) Polyclonal antibody = antibodies coming from different clones of lymphocytes (different epitopes); different lymphocytes have become plasma cells secreting antibodies.

Question 7

I identify normal, polyclonal gammopathy, and monoclonal gammopathy on a printout of serum electrophoresis.

Answer 7

Electrophoresis = Separates proteins based on charge; albumins are all the same so there is a narrow band present.