Immune System
The role of the M cell is to

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

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

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

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

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

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Immune System
T cell receptors (or TCR) on CD4+ T cells

recognize peptides associated with MHC class I molecules
are secreted out into the environment to bind antigens
recognize peptides associated with MHC class II molecules
recognize peptides not associated with MHC molecules

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