The immune response Flashcards
where are white blood cells made?
in the bone marrow (particularly in the pelvis and the ribs) and then released into the blood
what does the erythrocyte do?
carries oxygen around the body
what do platelets do?
clot the blood if there is bleeding
what cells are granulocytes
basophils, neutrophils and eosinophils
what are natural kills cells?
kill cells specifically virally infected cells or cancer cells
what are monocytes
give rise to special cells that live in tissues called macrophages
what do macrophages do
surveying tissue and repairing any damage
what are b lymphocytes
important within the adaptive immune response, make antibodies
what are t lymphocytes
important within the adaptive immune response can kill cells or make special proteins that enable other immune cells
where are t lymphocytes made?
in the bone marrow and then mature in the thymus to ensure they don’t cause damage when they are released
what cell is human blood largely made up of?
neutrophiles (60%) then lymphocytes (30%)
how do neutrophils
protect against infection?
they chase and eat bacteria
what cells move to and live in the tissues?
dendritic cells, macrophages and mast cells
where do T and B lymphocytes spend most of their time?
in secondary lymphoid organs in the nose and mouth
what cells make up the innate immune response?
mast cell, natural killer cell, neutrophil, basophil, eosinophil and monocytes
what is complement?
a cascade of proteins in serum, activated by antibody or molecules from pathogens. it amplifies the inflammatory response and can directly kill pathogens or attract other immune cells
what do macrophages do?
re organise their actin cytoskeleton to engulf bacteria that are digested inside the cell. can also engulf apoptotic cells using finger like extensions called pseudopodia
what is adaptive immunity
stimulated by exposure to microbe, it is more potent
what is innate immunity
immediate response and tends to be local, hard wired from birth
what is humoral adaptive immunity
when antibodies are mediated, ‘extracellular attack’ , antibody from B cells and B cells mature in the bone marrow
what is cell mediated adaptive immunity
intracellular attack due to T cells which mature in the thymus
where do T cells mature?
thymus
where do B cells mature
bone marrow
for one white blood cell how many red blood cells are there?
700
what is the lifespan in the blood of a neutrophil?
7 hours
what is the lifespan in the blood of a eosinophil?
8 to 12 days
what is the lifespan in the blood of a basophil?
few hours to a few days
what is the lifespan in the blood of a monocyte?
3 days
what is the lifespan in the blood of a B or T lymphocyte?
memory cells so can live for many years.
how long after infection does it take for the innate immune response to kick in?
0-12 hours roughly
how long after infection does it take for the adaptive immune response to kick in?
1-7 days
what distinguishes neutrophils?
distinct multi lobed nucleus (2-5 lobes), usually first cell to reach site of inflammation, after apoptosis they are the major constituent of pus
what are the largest circulating blood cells?
monocytes
what are some features of monocytes?
-present in chronic illness
-differentiate into macrophages in tissues which survive long term
-have TLR which recognise PAMP’s and destroy pathogens by phagocytosis
-can release cytokines
which cells primary function is to combat parasitic infections?
eosinophil, can poke holes in the outer layer of helminths
what are some characteristics of eosinophils?
-parasitic infection
-seen in allergic and certain malignant disease processes
-bilobed nucleus
what immunoglobulin works with basophils in the inflammatory response?
igE
IgA?
13%
found in breast milk, tears and other fluids, generally found in mucosa
prevents bacterial infection
IgM?
6%
develop in plasma, activate complement, reacts usually on first exposures
IgD?
found in most B cells important in activating B cells
IgG?
80%
activates complement, crosses placenta to protect foetus, active against bacteria and viruses
IgE?
associated with allergic reactions
where are mast cells found?
reside in tissues and are activated in response to pathogens or signals
how do mast cells contribute to the innate immune response?
release a number of inflammatory mediators
enhance vascular permeability
what are the key molecules involved in the innate immune response?
-PAMPs and DAMPs
-complement
-chemokines
-cytokines
-other inflammatory mediators
what is complement and what does it do?
made up of plasma proteins
1. oponise bacteria for phagocytosis
2. attract more phagocytic cells
3. directly kill bacteria
what do chemokines do?
attract neutrophils
what do cytokines and other inflammatory mediators do?
increase vascular permeability
what are the major cell types involved in the innate response?
phagocytes
NK cells
dendritic cells
mast cell
what are the major cell types involved in the adaptive response?
T cells, B cells, antigen presenting cells
what are CD8 cells?
cytotoxic t lymphocytes
how do lymphocytes recognise antigens?
T cell receptor complex on the surface, part of which CD3 identifies these cells.
how do CD8 cells induce apoptosis in virally infected cells?
release perforin into the cell membrane, create a pore and then inject granzymes which scrambles the DNA in the virally infected cells, causing apoptosis
which cells are not found in the blood?
mast cells, they are found in tissues
macrohages are also found in tissues not in the blood
what are the phagocytic cells?
dendritic cells
monocytes
macrophages
what is the name of the small molecules that attract other immune cells?
cytokines
What are T and independent B cells particularly important for dealing with?
Encapsulated bacteria
What is the term for the process when dendritic cells Sample pathogens they encounter?
Macrropinocytosis
What do MHC class I molecules interact with?
CD8 on cytotoxic T cells
Which cells are most important in killing virally infected cells?
Cytotoxic T cells
What activates CD4+ helper cells?
MCH class II molecules which are expressed on the surface of APCs
What are the functions of CD4+ T cells?
-activating other immune cells
-releasing cytokines
-help B cells produce antibodies
Which white blood cell manly targets bacterial and fungal infections?
Neutrophils
Which white blood cell is mainly responsible for allergens?
Basophils
Which white blood cell is mainly responsible for bacterial infections?
Monocytes
Which white blood cells is mainly responsible for viral infections?
Lymphocytes
What cells are agranulocytes?
Lack granules in cytoplasm
Which cell mainly links innate and adaptive response?
Dendritic cells
Which cells come from the lymphoid lineage?
Lymphocytes and NK cells
tay-sachs disease is associated with defective?
lysosomes
which cells come from the lymphoid progenitor cell lineage?
NK cells
T+B lymphocytes
plasma cell
what is the descending order of abundance in serum if antibodies?
G, A, M, D, E
what is the only antibody to cross the placenta?
IgG
which antibody is most prevalent in secretions?
IgA
which antibodies are the best at neutralising?
IgA and IgG
which antibodies activate the complement pathway?
IgM and IgG
which antibody is secreted as a pentamer?
IgM
