Immunology Flashcards
Which cytokines have anti-viral activity?
Interferons
Which cytokines control and direct cell migration?
Chemokines
Which cells produce antibodies?
Antigen-activated B cells
What lymphocytes have a regulatory effect on the immune system?
T helper cells
Where are the complement proteins synthesised?
In the liver
Where are monocytes found?
Circulating in the blood
How do macrophages help to limit inflammation?
They secrete anti-inflammatory cytokines and are involve in tissue repair and wound healing.
What is the half life of a neutrophil in the bloodstream?
6 hours
Which cells phagocytose antigens and mature and migrate to secondary lymphoid tissues where they play a key role in antigen presentation?
Dendritic cells
Name some primary lymphoid tissues.
Bone marrow
Thymus
Name some secondary lymphoid tissues.
Spleen
Lymph nodes
Peyer’s patch
What branch of the immune system is responsible for acute inflammation?
Innate
What molecules are expressed by pathogens that allow macrophages, mast cells, NK cells and dendritic cells to recognise self from non-self?
PAMPs (pathogen associated molecular patterns)
What receptors are expressed by innate immune cells, allowing them to bind to PAMPs?
PRR (Pattern recognition receptors)
How do macrophages recognise apoptotic cells?
During apoptosis, cells flip certain intracellular membrane lipids to the cell surface.
What anti-inflammatory cytokine is secreted by macrophages to limit host damage?
IL-10
What cytokine is able to induce superactivation of macrophages?
IF gamma
What abilities does a superactivated macrophage have?
Increased production of toxic oxygen and nitrogen species
Increased antigen presentation
How do healthy cells inhibit NK cells?
Healthy cells express MHC 1 displaying a self peptide. The NK cell can bind to this ligand and is inhibited.
Which cytokines activate NK cells?
IF alpha and IF beta
Which pro-inflammatory cytokine is secreted by NK cells?
IF gamma
What is the acute phase response?
Systemic response involving changed to the plasma concentrations of specific proteins in response to inflammation. Changes are due to altered protein synthesis in the liver.
How many subunits does CRP have?
5
Which cytokines stimulate the synthesis of CRP in the liver?
IL-6 and IL-1beta
What is the role of CRP in the acute phase response?
Enhances phagocytosis and activates the complement system
What inflammatory mediators are released by mast cells?
Histamine
TNFalpha
Leukotrienes
Prostaglandins
By what mechanisms can neutrophils eliminate pathogens?
Phagocytosis
Degranulation
Neutrophil Extracellular Traps (NETs)
Why is pus yellow?
Due to the high iron content of neutrophils
Describe the downstream events of the complement cascade in pathogen killing.
C3b cleaves C5 to C5a+C5b. C5b binds to pathogens. C6, 7, 8 and 9 assemble with C5b forming the membrane attack complex. It inserts into target cell walls causing osmotic lysis. (C5b, b for binding)
What is opsonisation?
The coating of pathogens by humoral factors to facilitate phagocytosis.
Which complement protein is an opsonin?
C3b
Which complement proteins are known as anaphylatoxins that promote inflammation?
C3a and C5a (a for anaphylaxtoxins)
Describe the nature of the response of the adaptive immune system.
Slow and specific to each antigen
In which part of the lymph node are opsonised antigens trapped?
Stromal B cell zones
Which MHC molecules present to CD8+ T cells?
MHC I
Which MHC molecules present to CD4+ T cells?
MHC II
Which cells express MHC II?
Professional antigen presenting cells e.g. dendritic cells, macrophages, B cells.
Why do plasma cells have lots of ER?
To churn out antibodies
Which Ig is the first produced during an immune response and responsible for activating B cells?
IgM
Which Ig exists as a pentamer in the plasma and secretory fluids?
IgM
Which Ig is most abundant in normal human serum?
IgG
Which Ig is transported across the placenta into the foetal blood supply to offer foetal immune protection?
IgG
What is the function of membrane bound IgD?
B cell activation
Which Ig is transported in breast milk?
IgA
What Ig is most important in mucosal immunity?
IgA
Which Igs trigger allergic reactions?
IgE
Which T cell cause superactivation of macrophages?
TH1
Which T cells cause proliferation and differentiation of B cells?
TFH
