Immunology Exam 3 Part 1 Flashcards
describe the barriers of the GI, lungs, and oral cavity
GI: simple columnar epithelium, microvilli, goblet cells
lungs: pseudostratified columnar epithelium, cilia, goblet cells
oral cavity: non-keratinized stratified squamous epithelium
what are the types of mucosa associated lymphoid tissues (MALTs)? are they primary or secondary lymphoid organs?
gut-associated
nasal associated
bronchus associated
secondary
describe gut associated lymphoid tissue
components: peyer’s patches, isolated lymphoid follicles
regional lymph nodes: mesenteric/iliac
describe nasal associated lymphoid tissue
components: tonsils, isolated lymphoid follicles
regional lymph nodes: cervical
describe bronchus associated lymphoid tissue
components: inducible in most species
regional lymph nodes: peribronchial/mediastinal
describe the function of M cells, goblet cells, and paneth cells in GI barrier
M cells facilitate transcytosis of antigens across enterocytes to present to immune cells
Goblet cells = mucins/mucous
paneth cells = antimicrobial proteins
most important anitbody for mucousal immunity
IgA
what is an inductive site vs an effector site
inductive site is a secondary lymphoid tissue where immune response is initiated (e.g. peyer’s patches (GALT), mesenteric lymph nodes, tonsils (NALT), BALT, peripheral lymph nodes)
effector sites are everywhere else (SI, LI, glands, bone marrow, cervix, inflamed non mucosal tissue)
what are the six types of antigen sampling methods
- paracellular transport across tight junctions
- apoptosis-dependent transfer
- antigen capture by transepithelial dendrites (TED)
- transcytosis (bulk & receptor mediated transport across M cells)
- FcRn-dependent transport
- uptake via goblet cells
what are involved in tolerance
anti-inflam cytokines like IL10 and TGF-beta
innate lymphocyte cells
Treg lymphocytes
IgA producing B cells
fibroblasts
what are involved in inflammation
proinflam cytoines like IL6 and IL1-beta
Th1, Th2, Th17
how is IgA transported to mucosal surfaces
- IgA J-chain binds to plgR on basolateral face of epithelial cell
- endocytosis of IgA
- transcytosis of IgA to apical face of epithelial cell
- release of IgA dimer at apical face
what are IgA effector mechanisms
-bind/neutralize pathogens/toxins on gut surface or internalized in endosomes
-export toxins/pathogens to apical surface while being secreted
-bind to Dectin-1 on M cell to allow transport of antigen to dendritic cell or any APC
describe the difference in serum IgA and mucosal IgA
serum IgA = pentamer
mucosal IgA = dimer
what are intraepithelial lymphocytes (IELs)? what are there effector mechanisms?
CD8+ cytotoxic T cells in the epithelial lining of the gut
- once virus infected mucousal epithelial cell, IELs will kill infected epithelial cell via perforin/granzymes and Fas-dependent pathways (apoptosis)
list the main effector mechanisms of mucosal immunity
memory T cells
natural effector/regulatory cells
mucins/mucous
IgA
antimicrobial peptides (AMPs)
distinctive microbiota
what is the difference between a mucosal and parenteral vaccine
parenteral - given elsewhere in the body other than mouth or alimentary canal, mainly systemic immunity
mucosal - given mouth/nasal cavity/alimentary canal; mucosal and systemic immunity
where do B cell originate in avians compared to mammals
Bursa not Bone Marrow
do birds have lymph nodes?
no lymph nodes, but build lymph node aggregates in areas of infection
what immunoglobulins do avians have
IgM, IgY, IgA
do NOT have IgD or IgE
how does the IgY chain in avians differ from IgG in mammals
IgY H-chain is longer, 5 domains, and no hinge region
what are heterophils?
avian equivalent to neutrophils
what are the differences in thrombocytes between mammals and avians
avian thrombocytes are phagocytic (reason why you do not what to drain abcesses)
do avian species have a simpler or more complex immune system? why?
simpler
lay eggs
how are the bursa in avians and thymus in mammals similar
both regress with sexual maturity
describe the difference in avian MHC complexes
minimal essential MHC
only 2 class I genes & 2 class IIbeta
usually only one is expressed making it harder to fight off intracellular pathogens
how to avian species generate antibodies compared to mammals
gene conversion
random recombination of pseudogene V sequences and rearranged sequences occur within bursa
what are avians primary lymphoid organs and function
Bursa - B cell production
Thymus - T cells
what are avian secondary lymphoid organs
spleen
harderian gland
cecal tonsils
peyer’s patches
meckel’s diverticulum
other (islet of lymphoid tissue or microbiota)
function of the harderian gland
IgA producing plasma cells, also some IgM and IgY
why is the spleen more critical in avians than mammals
site of progenitor B cell lymphopoiesis
site of interaction between lymphoid and nonlymphoid cells so due to avians lack of lymphatics, spleen is more critical
function of cecal tonsils
B and T cell production