Liver Flashcards
how is the dual-blood supply regulated in the liver?
nutrient-rich and oxygen-poor blood via portal vein from intestines and oxygen-rich blood via hepatic artery
name 3 immune responses in the liver
- protection against pathogens and food toxins entering from intestines
- removal of translocated intestinal bacteria and bacterial toxins
- tolerance to food antigens and commensal bacteria
name the 3 functions of the liver
- metabolism
- detoxification
- synthesis (systemic immunity)
name the 2 immunological functions of the liver
- synthesis of complement factors and PRR molecules that are important for systemic immunity
- local defense against gut-derived pathogens, bacterial product (LPS) and food toxins
what are acute phase proteins?
only secreted by the liver during an infection, production is stimulated by IL-6
what is C-reactive protein?
- acute phase protein secreted by the liver in response to inflammation
- PRR binds to phosphocholine on bacterial surfaces
- activates complement system via classical pathway
- marker for inflammation
what is MBL?
- acute phase protein
- trigger complement activation via lectin pathway
- PRR recognizes PAMPs in micro-organisms
true or false? transplantation of liver with MBL/ficolin-2/MASP-2 polymorphisms is associated with increased incidence of bacterial infections
true, when SNPs were found in all three proteins there is an increase of infections
how are endotoxins recognized in the liver?
macrophages recognize LPS, secrete anti-microbial factors and phagocytose bacteria
LBP transfers LPS to CD14 on myeloid cells and binds LPS to TLR4
tolerance from the liver is needed for …
endotoxins and food antigens
hepatic immunity is needed for …
hepatitis A and B virus, bacteria
when is there unwanted tolerance?
hepatitis B and C virus, plasmodium sporozoite (malaria) and tumor metastases
name 4 reasons why the liver is less immunogenic
- HLA-matching not required
- low incidence of chronic rejection
- liver transplantation confers protection against rejection of other organ grafts from the same donor
- withdrawal of immunosuppressive medication is possible in part of stable LTx-patients without graft rejection
which immune cells are present in the liver (portal tracts and sinusoids)?
- Kupffer cell; phagocytic and APC
- dendritic cell
- NK cells
- T cells
- liver sinusoidal endothelium cells (LSEC); endocytic and APC
what is the function of liver sinusoidal endothelium cells (LSEC)?
- detection and capture of pathogens, proteins and toxins
- removes waste products and pathogens via receptor-mediated endocytosis and lysosomal degradation
- APCs with tolerogenic properties