A Mouse Is Infected with Staphylococcal Bacteria Through a Laceration

question 10

Multiple Choice

A mouse is infected with staphylococcal bacteria through a laceration in the skin of its paw. Dendritic cells are isolated from the tissue at the site of infection, and are incubated together with naïve staphylococcal-specific CD4 T cells. Seventy-two hours later, the proliferation of the CD4 T cells is measured as a readout for T cell activation. Surprisingly, the T cell response is quite poor compared to the response observed when the same T cells are mixed with a comparable number of dendritic cells isolated from the draining lymph node of the infected mouse. A comparison of the dendritic cells isolated from the two different sites would reveal:

• A) Much higher levels of MHC and B7 molecules on the lymph node dendritic cells than those from the infected tissue
• B) Much higher expression of all TLRs in the lymph node dendritic cells than those from the infected tissue
• C) An increased number of MHC class II molecules bearing bacterial peptides on the surface of dendritic cells from the infected tissue than on those from the lymph node
• D) Increased phagocytic activity of the lymph node dendritic cells than those from the infected tissue
• E) Increased expression of Dectin-1, DEC205, and DC-SIGN on the lymph node dendritic cells than on those from the infected tissue

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Definitions:

Oxytocin

A hormone and neurotransmitter involved in childbirth and lactation, also known to play a role in bonding, social behaviors, and stress relief.

Epigenetic Marks

Chemical modifications to DNA or histones that can affect gene activity without changing the DNA sequence, often as a result of environmental factors.

Gene Expression

The process by which the information encoded in a gene is used to direct the assembly of a protein molecule, influencing an organism's traits.

Neurotransmitters

Chemical substances in the nervous system that transmit signals from one neuron to another.