Immune System
Numerous antibodies can be prepared, against one antigen, each binds to unique epitopes. How is this antibody diversity generated?

By the combination of different heavy and light chains that form the antigen binding site
Antibody proteins can physically change their shape to bind different epitopes
Both (a) and (b)
By rearrangements of the DNA encoding the variable regions of the heavy and light chains

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Immune System
The role of the M cell is to

pass bacteria or virus to underlying macrophages for processing and presentation of antigen
induce apoptosis in virus-infected small intestinal epithelia cells
trap virus in mucus and prevent entry
they use their cilia to propel mucus out of the small intestine

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Immune System
Which of the following is correct for CD8 T cells?

CD8 T cells can kill individual virus-infected cells in a contact dependent fashion
CD8 T cells only recognize virus-infected cells
CD8 T cell receptor recognizes epitopes that are also commonly recognized by B cells
In the thymus, CD8 T cells undergo positive selection only, whereas CD4 T cells undergo negative selection only

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