Immunology Flashcards
what do peyer’s patch cells (paneth cells) do?
they sample antigens from the lumen and deliver them to antigen-presenting cells
what are alpha defensins?
primarily, they serve to penetrate into microbial cell membranes to disrupt them and kill the microbe; they are also T cell and dendritic cell chemoattractants, they also activate the complement
where are alpha defensins made?
they are made in neutrophils and in paneth cells - they are constitutive
what are beta defensins?
they are molecules that insert into the membranes of microbes and disrupt them, killing the microbe; they also act as chemoattractants for dendritic cells and T cells
where are beta defensins made?
they are made in epithelial cells and are inducible by LPS/endotoxin from bacteria and by TNFalpa
where is the complement made?
in the liver and circulates in the plasma
how is the classical pathway of the complement initiated?
C1 binds to antigen/antibody complexes and activates C3 convertase
how is the lectin pathway of the complement initiated?
mannose on bacterial cells binds to mannose binding lectin receptors and leads to C3 convertase formation
how is the alternative pathway of the complement initiated?
by microbial surfaces come into contact with cell surfaces
what do C3a, C4a, and C5a do?
they signal histamine release
what is C5a chemotactic for?
leukocytes**
how does C3b function?
as an opsonin, targeting microbe for phagocytosis
how do C5b and C6-C9 function in the complement system?
they form the MAC (membrane attach complex) which puts pores in cell membrane and causes lysis
what are some soluble mediators that neutrophils release?
IL-1, MIPa/b, GROa, MCP1
what are the two ways to activate macrophages?
classic and alternative pathways
