Lecture 2 Flashcards
what are inductive sites?
places where antigens are picked up and presented to naive b and T cells.
what are effector sites?
where stimulated cells travel to and mediate their function
what is malt?
mucosal associated lymphoid tissues, they are the inductive sites within some mucosa
what are examples of effector sites?
the lamina propria, exocrine glands and surface epithelia.
do lungs have malt?
they have malt in early days of life which later disappears
epithelial cells are polarised, what does this mean?
they have a specific membrane and lipid composition and cellular features.
what is the outer surface of epithelial cells called and what does it face?
called the apical membrane and it faces air (skin, lungs) or fluid-filled organ cavities (the lumen of the gut)
what are some potential features of the apical membrane?
it may have cilia (movement) or be highly folded forming microvilli to increase the surface area.
what are the inner surfaces of epithelial cells and what do they rest on?
basolateral membranes rest on ecm called the basal lamina
what is transcytosis?
vesicular mediated transport of internalised material of endogenous (e.g. SIgA) or exogenous (microbes) origins. from apical -> basolateral or basolateral -> apical.
what do m cells (microfold cells) do?
they take up things from the apical side such as antigens.
what are the three main malt tissues and where are they found?
NALT- nasopharynx, respiratory and digestive tract
BALT- respiratory tract
GALT- digestive tract
why is there no malt in the urogenital tract?
to aid reproduction as the embryo is seen as a foreign body.
what is a problem of the mucosal immune response?
there’s a physical barrier between the mucosal antigens and the immune effector cells.
what two ways can antigens be sampled by specialised cells?
m- cell antigen uptake via endocytosis or phagocytosis, followed by transcytosis.
cross-epithelium dendritic cells can sample antigen from the lumen of the mucosa via cellular extensions.
what occurs after antigens are sampled?
IgA and IgM are transcyotsed into the lumen of mucosa where they contribute to pathogen elimination.
what happens when b and T cells are stimulated?
they migrate into the draining lymph node, and from there reach the vascular system so now they can go to any site.
why is there a specific homing system?
if there’s an antigen found in the small intestine, peyer’s patch for example, the immune cells repopulate any length of the small intestine, even colon, preventing further infections.
what recruits lymphocytes to epithelial cells?
chemokine recruit the lymphocytes and the receptors on epithelial cells take up the lymphocytes, allowing them to migrate across the tissue.
which immune system is the NALT connected to?
both the mucosal and systemic so live vaccine through the nose induces a systemic and mucosal immune response.
