1. The class of immunoglobulins which can cross the placenta is

A. IgM
B. IgG
C. IgA
D. IgD

2. Self reactive antibodies are not found in significant concentration in normal serum because

A. it is impossible to generate a self-reactive antibody
B. self reactive B cells are killed by CD8 T cells
C. B cells that are stimulated via their surface bound antibody in the absence of T cell help to commit suicide
D. self reactive B cells switch to IgA which is all secreted and not present in serum

3. Simulation of which of the following will lead to appearance of first antibody to appear following stimulation by an antigen?

A. IgM
B. IgA
C. IgE
D. IgG

4. Antigen binding sites of an immunoglobulin are located in

A. light chain alone
B. heavy chain alone
C. F_c region of the antibody
D. Fab regions of the antibody

5. Which of the following mediates Type I hypersensitivity reaction?

A. IgE
B. IgG
C. IgM
D. IgD