Question 1

Which of the following is NOT a normal part of commensal microbiota?

Accepted Answer

E

Question 2

Which part of our body is the BEST example of a barrier organ?

Accepted Answer

The skin acts as the primary barrier between the internal organs and the external environment, protecting against physical, chemical, and biological harm.

Question 3

What mechanism is NOT used by epithelial cells to prevent the invasion of barrier tissues?

Accepted Answer

Epithelial cells primarily serve as a physical barrier and produce substances like antimicrobial peptides and mucus to prevent microbial invasion. They do not typically engage in phagocytosis; this function is carried out by specialized immune cells such as macrophages and neutrophils.

Question 4

Peyer's patches and isolated lymphoid follicles are components of

Accepted Answer

Peyer's patches and isolated lymphoid follicles are components of the gut-associated lymphoid tissue (GALT), which plays a crucial role in the immune response within the gastrointestinal tract.

Question 5

Which of the following is a tolerogenic cytokine?

Accepted Answer

Tolerogenic cytokines are those that help to promote immune tolerance, often by suppressing immune responses. TGF-β (Transforming Growth Factor-beta) and IL-10 (Interleukin-10) are both well-known for their roles in inducing tolerance and suppressing inflammatory responses. IL-1, on the other hand, is typically associated with pro-inflammatory responses.

Question 6

MOST immune cells in the gut can be found in the

Accepted Answer

The lamina propria, a layer of the mucosa, is rich in immune cells, including lymphocytes and macrophages, which play a crucial role in gut immunity.

Question 7

What is the meaning of the gut epithelial cells being "polarized"?

Accepted Answer

Polarization in epithelial cells refers to the presence of distinct structural and functional differences between the apical (facing the lumen) and basolateral (facing the blood supply) sides of the cell, which is crucial for their function in absorption and secretion.

Question 8

Which of the following statements is TRUE regarding microfold (M) cells and goblet cells?

Accepted Answer

Both M cells and goblet cells are involved in the transport of antigens across the epithelial barrier to the immune cells. M cells are specialized for antigen uptake and delivery to underlying immune cells, while recent studies have shown that goblet cells can also participate in antigen transport through a process known as goblet cell-associated antigen passages (GAPs), involving transcytosis.

Question 9

What would you expect to observe in a suburban Philadelphia patient who was unable to make IgE antibodies?

Accepted Answer

IgE antibodies are primarily involved in allergic reactions and defense against parasitic infections. A patient unable to make IgE antibodies would likely have a lack of allergies and asthma, which are typically mediated by IgE.

Question 10

Which of the following is NOT an antimicrobial molecule secreted into the intestinal lumen?

Accepted Answer

Enterocytes are not antimicrobial molecules; they are the absorptive cells in the lining of the small intestine, responsible for nutrient absorption. Defensins, AMPs (Antimicrobial Peptides), REG3 family proteins, and Lysozyme are all examples of antimicrobial molecules secreted into the intestinal lumen to protect against pathogens.

Question 11

Retinoic acid is

Accepted Answer

Retinoic acid is a metabolite of vitamin A and plays a crucial role in the immune system, including the induction of a tolerogenic response, which helps in the maintenance of immune tolerance and prevention of autoimmune responses. It does not have a direct role in killing pathogens in the gut.

Question 12

Compared to the small intestine, the microbiome in the large intestine is

Accepted Answer

The large intestine hosts a more diverse and larger microbiome compared to the small intestine. This is due to the slower movement of waste, which allows for a greater variety of bacteria to colonize and thrive in the large intestine.

Question 13

Both celiac disease and ulcerative colitis

Accepted Answer

Both celiac disease and ulcerative colitis are inflammatory diseases that affect the gut. Celiac disease primarily affects the small intestine, while ulcerative colitis affects the colon.

Question 14

Which of the following is NOT a risk factor for inflammatory bowel disease?

Accepted Answer

All of the options listed (NOD2 mutations, low tryptophan levels, CARD9 mutations, and increased levels of IL-23) are recognized as risk factors for inflammatory bowel disease (IBD). These factors are associated with the immune response and gut microbiome, which play significant roles in the pathogenesis of IBD.

Question 15

Which of the following pathogens invades epithelial cells directly?

Accepted Answer

Salmonella typhimurium is known for its ability to invade and replicate within epithelial cells, which is a key step in its pathogenesis.

Question 16

Which gut disease is MOST closely associated with antigen presentation?

Accepted Answer

Celiac disease is most closely associated with antigen presentation because it is an autoimmune disorder where the body's immune system attacks its own tissues when gluten is ingested. This process involves the presentation of gluten peptides by antigen-presenting cells to T cells, leading to an inflammatory response in the small intestine.

Question 17

Which of the following is ONLY found in the respiratory tract - and NOT the GI tract?

Accepted Answer

The mucociliary layer is a specialized feature of the respiratory tract, helping to trap and move particles out of the airways.

Question 18

Nasal-associated lymphoid tissue (NALT) MOST closely resembles

Accepted Answer

The answer of Nasal-associated lymphoid tissue (NALT) MOST closely resembles
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Question 19

Which of the following is NOT a response to H.influenza infection?

Accepted Answer

Mast cells are primarily involved in allergic reactions and are not directly involved in the response to Haemophilus influenzae infection. NK cells, Type I IFNs, TLR pathways, and alarmins all play roles in the immune response to bacterial infections, including H. influenzae.

Question 20

When available, humans are able to receive an intranasal vaccine for which disease?

Accepted Answer

The intranasal vaccine is available for influenza, known as the nasal spray flu vaccine. It's a form of live attenuated influenza vaccine (LAIV) designed to be administered as a spray into the nose, offering a needle-free option for vaccination against seasonal influenza.

Quiz 13: Mucosal Immunity and the Microbiome