Immune System
Polymorphonuclear leukocytes (or PMNs)

can be attracted to the site of an infection following activation of complement
are a type of phagocyte that can engulf and kill bacteria
All of these
are derived from bone marrow stem cells

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

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

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Immune System
Which of the following statements is false regarding B cells?

B cells can undergo class switching and produce a different antibody type
B cells synthesize antibodies and put them on their cell surface
B cells that recognize high concentrations of antigens (self) in the absence of other signals undergo apoptosis in the bone marrow
B one marrow stem cells migrate to the thymus and develop into B cells

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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
trap virus in mucus and prevent entry
they use their cilia to propel mucus out of the small intestine
induce apoptosis in virus-infected small intestinal epithelia cells

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