Immune System L31 Flashcards
What happens first in infection at a wound
Phagocytosis, complement, amp release at epithelial, apc (dendritic)
Where does dendritic apc go to and what happens
Down lymphatics to lymph node and activates B and T cells via antigen/MHC
These then released eg antibodies and Th cells and this causes attraction of phagocytes, NK, eosinophils etc
How are intracellular cytoplasmic pathogens killed
Cytotoxic T cells
NK cells
(Both have perforin and granzymes)
How are intracellular vesicle pathogens dealt with
T cell or NK cell activation of macrophages
What is indirect pathogenicity
Symptoms from immune reaction
Give examples of indirect pathogenicity via immune system
Host cell - antibody response
Immune complexes (antigen antibody clumps)
Cytotoxic damage to normal host cells
What are the 2 types of leprocy
Tuberculoid (mild)
Lepromatous (severe)
Why is tuberculoid leprocy easier to deal with
Normal T cell response, local inflammation, TH1 response eg via IFN y = phagocytosis
Which antibody is high with lepromatous leprosy
IgG
Which Th response happens with lepromatous leprocy which is inappropriate
Th2- causes IgE switching and mast cell activation etc and eosinophils
Eg via IL 4
What is difference between primary and secondary immunodeficiency
Primary - rare genetic defect
Secondary- immunosuppressives, stress, pregnant
Why would things like herpes 8 and hepatitis C cause tumours in immunodeficiency
Lack of ability for NK cells/ cytotoxic cells to fight off tumour cells
Herpes and hep can introduce oncogenes to grow Tumour cells
Which deficiency causes lack of B cells and antibodies to fight extracellular/ free pathogens
X linked a gamma globulin anaemia
What would grow if there was iga deficiency
Pathogens in secretory areas eg respiratory tract
What is immunopathology
Excessive immune response eg autoimmune, allergy , infection
How is covid an immunopathology
Causes unregulated cytokine storm when epithelial cells engulfed
Cause low lymphophenia in blood (go to tissues)
What are type 1-3 hypersensitivity caused by
Antibodies
Give example of type 1 hypersensitivity via antibodies
Ige over stimulation via allergy antigens eg pollen to bind to fc receptors on mast cells to release histamine
What can type 1 hypersensitivity usually cause
Anaphylaxis as too much vasodilation , bronchospasm via histamine
Give an example of type II hypersensitivity
Crossing of igG eg anti rhesus antibody to placenta and child with rhesus +ve causes anemia (lysis of rbc)
What is a disease caused by type III sensitivity
Lupus
What happens in type III lupus
Autoantibodies IGG form complex with host dna antigens and cause deposits = rash etc
What is type IV hypersensitivity
Cell mediated attack
What is an example of type IV hypersensitivity
Diabetes
Pancreatic B cells with mhc 1 are killed by cytotoxic CD8
