Immune 2 Flashcards
Whole blood contents
Plasma (55%)
- proteins (including antibodies / immunoglobulin
- other solutes
- water
Formed elements (cells) 45% - fall to the bottom when spun in a centrafuse forming a pallet
- platelets (important for clotting)
- white blood cell (leukocytes)
- red blood cells
What is the source of blood cells
- bone marrow stem cells (pluripotent) that develop into blood cells (hematopoiesis)
Three blood cell lineages that can arise from stem cells in bone marrow
- erythroid —-> red blood cells (erythrocytes)
- myeliod ——> granulocytes, monocytes, dendritic cells, platelets (cells that form innate immune cells) - WHITE BLOOD CELLS
- Lymphoid ——> B and T lymphocytes (adaptive immune cells) - WHITE BLOOD CELLS
All are derived from hematopoietic stem cells in bone marrow
Grandulocytes in blood example
Neutrophils - 75% of all leukocytes (white blood cells) , highly phagocytic “eat and kill” - numbers in blood increase during infection
What do granulocytes in blood do during inflammation?
- granulocytes circulate in the blood and can move into tissue during inflammation
Granulocytes in tissues - THE MAST CELL
- the mast cells line mucosal surfaces (not found in blood)
- release granules (bio active substances) (in dark purple) that attract white blood cells to areas of tissue damage
Monocytes and macrophage in the blood vs tissues
- monocytes present in blood —- > low phagocytosis
- leave blood - develop into macrophages in tissues e.g spleen, liver ——-> high phagocytosis (eat)
How do macrophages move?
- macrophage become resident in a particular tissue (sessile) or move through tissues (migratory)
Three important functions of macrophages
- Phagocytosis (proffecsional eaters)
- Release of chemical messengers (to talk to other cells)
- Show information about pathogenic microbes that they’ve ingested to T cells (linking innate and adaptive immunity)
What does the dendritic cells do?
Iink innate and adaptive immune responses
Dendritic cells
- most important cell type to help trigger adaptive immune responses
- phagocytic
- found in low numbers in blood and all tissues in contact with the environment (because they are potent)
- large surface area so it can interact really well with multiple cells at the same time
How do cells of the immune system move around the body?
- Cells are carried in the blood and lymph
- cells can leave the blood to enter tissues
- lymph in tissues collects into lymphatic vessels - these drain lymph into lymph nodes
(if there is a pathogen while in lymph node - dendritic cells are able to talk to other adaptive cells such as T cells to alert them to the fact they need to start preparing or getting ready for the infection- LECTURE TALK)
Pathogen- associated molecular patterns - VIRUSES
Common building blocks: nucleic acid - ssRNA, dsRNA
- innate building block recognises the dsRNA that is not usually in Eukaryotes as well as ssRNA
Pathogen- associated molecular patters - BACTERIUM
Common building blocks:
- cell wall: LPS (recognised by innate immune cells)/endotoxins, lipoteichoic acid
- flangella: flagelin
- nucleic acid: unmethylated CpG DNA - Regongises it as different cos its different from our cells
Pattern recognition receptors - how innate cells recognise pathogens
- can recognise components that form bacteria cell wall or a yeast cell wall - receptors (toll-like) bind to components and send a signal down to the nucleus of the cell to change gene transcription - can regulate production of things needed at that moment to kill the pathogen and down reugakte things that aren’t - so once pathogens bind to receptor on cell - it changes the proteins made within the cell
- cell wall components are regognised by receptors on cell wall
- pattern recognition receptors also exist within the cell
- when a phagocytic cell eats a pathogen it forms a membrane bound vesicle within the cell - this is called a phagolysosome
- inside the membrane the pathogen gets broken down and it’s nucleic acids are then released inside the phagolysosomme - on the membrane are toll like receptors which are able to recognise nucleic acids from bacteria or viruses the receptors send signals to the nucleus to alter gene transcription appropriately
Toll like receptors may be - heterozymers - two different protein components or homodymers - two similar some are just single
All this helps arm the cell more effectively and communicate with other cells
