Exam 3 - Dr. Sullivant

What surfaces have a mucosa?

respiratory, gastrointestinal, urogenital, reproductive, conjunctive, and mammary glands

What does an over-active gut immune system cause?

Chronic IBD/IRE

What does an over-response to a respiratory infection cause?

chronic bronchitis

What can happen with the mucosal immunity is ocerwhelmed?

pneumonia and acute hemorrhagic diarrhea syndrome

What is able to boost natural mucosal responses to pathogens?

vaccines

The mucosal surfaces of the body cover vital organs that communicate material and information between what?

the body and its environment

What percent of the immune system’s cells are dedicated to the mucosal surface defence?

75%

What is the largest part of the immune system (bc skin doesn’t count)?

Gut

What continuously samples the gut’s luminal contents and stimulate adaptive immune responses to pathogens, commensal organisms and food?

Secondary lymphoid tissues

The combined area of the mucosal surfaces is much greater than that of the skin; the small intestine alone has a surface area _____ times that of the skin

200x

What about percent of the body’s lymphocytes are in secondary lymphoid tissues serving mucosal surfaces?

75%

What are IgAs secreted as?

dimers

What is the majority of antibodies made by the body secreted as?

IgA

What is the large populations of commensal microorganisms found in the GI tract?

microbiome

What are the three major challenges for mucosal immunity?

eliminate pathogens, limit growth/location of commensal microorganisms, and do not attack the microbiota/food

What is the major challenge for mucosal immunity summarized to?

avoid immune-mediated disease

If bronchioles collapse, the risk of bacterial infection: increases or decreases?

increases

What is specialized lymphoid tissue in mucosal epithelium/lamina propria/submucosa?

MALTs

Where is MALT found?

mucosal epithelium, lamina propria, and submucosa

What are the five types of MALT's?

CONALT, NALT, CALT, BALT, GALT

What are the three main mucosal defenses?

physical barriers, innate immunity, and adaptive immunity

What is the first line of defense for the mucosal areas?

physical barrier

What are three physical barriers of mucosal defense?

Epithelial layer, microbiota, and mucus later

What is secreted by goblet cells in the mucosa?

mucin

Does the innate immunity of mucosa require previous exposure?

no

Does the innate immunity of the mucosa provide future protection?

no

What are three examples of innate immunity of the mucosa?

secretions of epithelium, complement cascade, and inflammatory cascade

What activates adaptive immunity?

cytokines/interleukins from innate immunity

What immunoglobulins are secreted into the surface epithelium?

IgM and IgA

What triggers phagocytes?

receptor-mediated recognition of pathogens

What on phagocytes recognize microbial patterns?

TLRs

What do NK cells trigger in intracellular viruses?

apoptosis

Once macrophages phagocytize where are the swept away to?

lymphatics, airways, or mucociliary apparatus

What immune response is necessary for hematogenously spread infections?

adaptive

What cytoplasmic receptors recognize intracellular pathogens and release lots of cytokines?

NOD-like

What to PAMPS bind to?

PRRs

What serves as a major APC to T helper cells, thus triggering the adaptive immune response (link between innate and adaptive)?

dendritic cells

What cells are involved in the MALT adaptive immune response?

dentric cells

What cells can extend processes across the epithelial layer to capture antigen from the lumen of the gut?

Dendritic cells

Where are CD4 + T helper cells?

MALT

What are the APCs?

Macrophages, dendritic cells, enterocytes

What type of innate cells present Ag to T helper cells in the mucosa to trigger the start of adaptive immunity?

APCs

What is the first step of adaptive immunity?

activation of t and b cells after ag presentation to t helper cells

What is the second step of adaptive immunity?

circulate in blood and lymph

What is the third step of adaptive immunity?

Educate t and b cells in lymphatics

What are the very specialized tissues of adaptive immunity in cows, which are located in the lower GI tract?

payer’s patches

How long does it take for adaptive immunity to kick in?

several days

What cells reside in mucosal tissue for rapid responses to reinfection of pathogens?

memory cells

What adaptive immunity effector cells are highly specific?

IgM, IgA, IgG, IgE

What can be differentiated from CD4+ t cells?

TH17 and TH2

What breaks down foreign antigens into peptides?

APCs

Foreign antigens are taken up by APCs, broken into small peptides, and presented on the APC cell surface in association with what?

class I or II molecules of the MHC

What recognizes the MHC peptide complex?

T helper lymphocytes

What activates t helper lymphocytes?

co-stimulatory surface molecules and cytokines

Where are naive lymphocytes activated?

mucosal tissuss

After naive lymphocytes are activated in the mucosal tissues, where do they go?

back as effector cells

What are most immune system cells in the mucosal tissues?

activated effector cells

What are the two main mechanisms for the removal of mucosa pathogens?

immune exclusion and elimination

What mechanism of pathogen removal uses the production and excretion of IgA onto the mucosal surface?

Immune exclusion

What immunoglobulin is associated with immune exclusion?

IgA

What immunoglobulin is associated with elimination?

IgG

Where is the IgG of elimination found?

serum

When does IgG enter into mucosal tissues?

after inflammation has started

What prevents mucosal effector cells from killing self?

tolerance

What do cells look for when learning to tolerate your own cells?

self-antigens

What are the self antigens derived from?

environment, diet, or microbiota

What is THE mucosal antibody?

IgA

What secretes IgA?

plasma cells underneath the epithelium

What does IgA do?

prevent pathogens from binding and entering mucosal epithelium

Where is IgA secreted onto?

mucosal surfaces

T/F Serum IgA = mucosal IgA

FALSE

T/F Secretory IgA can bind to pathogens in several locations

TRUE

What is very well-developed, extensive MALT?

GALT

T/F There is a vast microbiome in the GALT

TRUE

What does the GI microbiome do to carbohydrate through fementation?

produce SCFA and other postbiotics

What vitamins are synthesized by the GI microbiome?

vit K, B12, folate, and biotin

What are the four physical/chemical barriers of the GI?

peristalsis, ge secretions, acidity and mucus

Where are Peyer’s patches heavily concentrated?

ileum in the submucosa

What are the specialized epithelial cells at the apex of peyer’s patches?

M cells

What cells carry Ag to Peyer’s patches?

M cells

What does the M in M cell stand for?

microfold or multifenenstrated

Where do M cells up take antigens from?

gut lumen

How do M cells take up antigens from the lumen?

endocytosis

What take up the antigens released from M cells?

APCs

T/F Chronic GI diseases may develop from an exaggerated or inappropriate immune response in the gut

TRUE

What are examples of chronic enteropathies that can develop from an inappropriate immune response in the gut?

IBD/IRE and FRE

What can lung infections/pneumonia/inflammation spread?

hematogenous spread via the vasculature

T/F When MALT is over-active, it can cause chronic disease

TRUE

What can exaggerated MALT responses and breakdown of physical barriers lead to in the lungs?

acute lung injury

NALT

nasal associated lymphoid tissue

BALT

tracheal and bronchial lymphoid tissues

What increases mucosal contact tie and pathogen trapping in the respiratory tract?

tubulent airflow and airway branching

What type of junctions are found in the respiratory epithelium?

tight junctions

What moves in a direction toward the mouth to propel mucus and its entrapped particulates and microorganisms out of the airway via cough, sneeze, or swallow?

cilia on the apical surface of the epithelium

What are the 5 physical barriers of the respiratory tract?

bilayered mucus, sneeze, cough, mucociliary elevator, and closure of glottis

What is the top layer of mucus in the Respiratory tract?

thick, gel-like for trapping

What is the bottom layer of mucus in the Respiratory tract?

soluble where cilia beat

When does the glottis close?

during swallowing

When is the glottis open?

when you are not swallowing

What antibodies protect the pulmonary parenchyna?

IgG and IgM