The mucosal immune system is composed purely out of the three “tracts”. True or false?
False. It also includes other organs not part of the “tracts”, such as the salivary glands
What tracts make up the mucosal immune system?
Gastrointestinal tract
Respiratory tract
Urogenital tract
Commensal bacteria found on the mucosal tract are harmful to the host. True or false?
False. This is where most of them are actually.
Commensal bacteria, if located on the wrong “spot”, can be considered pathogenic. True or false?
False. They are non-pathogenic
Commensal bacteria do not help the immune system directly. True or false?
False. They actually prevent pathogens from benefiting from the resources of the human gut and can trigger the epithelium to develop secondary lymphoid tissue
If you remove commensal bacteria from the host, the number of autoimmune diseases and allergies increase. True or false?
True
In the gut IS, the presence of a thick mucus layer keeps most microorganisms in the lumen away from the intestinal epithelium. True or false?
True
In the gut IS, antimicrobial peptides cannot be produced as that would kill pathogens and commensal bacteria alike. True or false?
False. Antimicrobial peptides produced by intestinal epithelial cells that kill pathogens in the lumen or reduce their entry into the epithelium.
IgG produced by epithelial cells in the lamina propria, which is transported into the lumen and neutralizes pathogens before they can enter through the epithelium. True or false?
False. It’s IgA that is produced and its by plasma cells.
What do goblet cells do?
They produce mucus
A reduction in goblet cells leads to:
increased risk of inflammatory bowel diseases
What cells in the intestinal immune system secrete antimicrobial peptides?
Paneth cells
Mircofold cells are in charge of antigen sampling but cannot transport microbes. True or false?
False. They can transport microbes. I think.
M cells have a “pocket” that allows them to have close contact with immune cells. True or false?
True
M cells allow mucosal immune cells to sample antigens in the gut and make an appropriate immune response by causing overt inflammation. True or false?
False. This prevents overt inflammation.
What is the purpose of mucus in intestinal epithelial cells?
Prevent adhesion of microbes to epithelial cells
What’s a tight junction?
It’s what keeps intestinal epithelial cells close together
What is the function of PRR in the intestinal mucosa?
It minimizes the inflammatory response to commensal bacteria in the lumen, but promotes the response against microbes that traverse the barrier and enter the lamina propria
In healthy individuals, macrophages in the gut LP don’t inhibit inflammation as a way of maintaining homeostasis. True or false?
False. They inhibit inflammation.
Innate Lymphoid Cells have to be activated by cytokines. True or false?
True.
In the gut, what happens when a microbe is detected?
Innate Lymphoid Cells like Dendritic cells and Macrophages begin secreting IL-12 and IL-18
This stimulates ILC1 responses to fight against intracellular pathogens, while also stimulating IL-23 and IL-1B, which induce ILC3 responses against extracellular bacteria and fungi.
Mention the function of each of the following ILs:
IL-12
IL-18
IL-23
IL-1B
IL-33
IL-25
IL-22
IL-12 - Stimulate ILC1 response (anti-intracellular pathogens)
IL-18 - Stimulate ILC1 response (anti-intracellular pathogens)
IL-23 - Induce ILC3 (anti-extracelular bacteria and fungi)
IL-1B - Induce ILC3 (anti-extracelular bacteria and fungi)
IL-33 - Secretion of type 2 cytokines (anti-helminths)
IL-25 - Secretion of type 2 cytokines (anti-helminths)
IL-22 - Epithelial integrity and tissue repair
In the gut, the major form of adaptive immunity are plasma cells (IgG). True or false?
False. They are IgA
In the genital tract, the major form of adaptive immunity are plasma cells (IgG). True or false?
True
