1. Which of the following is NOT true for antigens?
a. An antigen is any agent that can bind specifically to components of the immune system.
b. Epitopes are the smallest part of an antigen molecule capable to bind with an antibody.
c. Proteins, carbohydrates, lipids, and nucleic acids can all be antigens under certain circumstances.
d. Proteins are the least immunogenic molecules due to very few epitopes for antibody recognition.

2. Self-antigens are coded by a group of genes located on chromosome and form the MHC (major histocompatibility complex).
a. 21
b. 8
c. 6
d. 5

The antibody found in body secretions is
a. IgA.
b. IgD.
c. IgE.
d. IgG.