immunology Flashcards
megakaryocytes become
platelets
reticulocytes become
RBC
myeloblasts become
neutrophils
monocytes -> macrophages
eosinophils
basophils
myeloid stem cells become
megakaryocytes
reticulocytes
myeloblasts
mast cells
pluripotent haematopoietic stem cells become
myeloid stem cells
lymphoid stem cells
dendritic cells
lymphoid cells become
b cells
t cells
natural killer cells
b cells become
plasma cells
memory b cells
t cells become… which then become…
CD4 cells -> T helper cells (activate CD8 cells to become cytotoxic T cells)
CD8 cells
briefly describe innate immune system
cells already at location of infections
respond immediately
generalised response
briefly describe specific immune system
takes longer than innate esp if first infection
specialised
away from location of infection
what do both mast cells and basophils contain
cytoplasmic granules containing cytokines released in response to pathogen
function of macrophage
first line of defence
have toll-like receptors used to recognise pathogen associated molecular patterns (PAMPs)
define PAMPs
pathogen associated molecular patterns that are recognised by toll like receptors on macrophages
function of neutrophil
general attack cell in innate immune system
circulate in blood and migrate to areas of inflam in response to macrophage signals
Fastest responding WBC
Antigen presenting
Release lysosomes, defensins and strong oxidants that directly destroy bacteria
function of eosinophil
parasitic infection
stay in tissues until activated
granules contain pro-inflam cytokines & toxic chems eg. ‘major basic protein’ - released in degranulation/exocytosis process
function of b cell and its differentials
antibodies (immunoglobulins) on outside of cell
they match to antigens displayed on pathogen
once activated, they differentiate into plasma cells (produced lots of that specific antibody) and memory B cells (await future infection)
function of t cell and its differentials (big boi)
have specific t cell receptors on surface to recognise antigens differentiate into CD4 and CD8 cells CD4: respond to HLA class II, become T helper cells which activate CD8 to differentiate into cytotoxic T cells (cell lysis and FAS pathway) CD8: respond to HLA class I
function of natural killer cells
activated by cytokines from macrophages and interferons
don’t require receptor antigen recognition to be activated
induce cell death (apoptosis)
release interferon gamma to activate macrophages (cycle of posi feedback)
function of dendritic cells
present antigens of pathogens on cell membrane
have HLA class I & II (for both CD4 & CD8)
act as postman - carry antigens through lymphatic tissue to T cells
physical barrier examples
skin - blocks bacteria but break in this can lead to infection
mucosa of: resp system, GI tract, urinary tract
chemical barrier examples
HCl of stomach
lactic acid of vagina
lysozyme in sweat and tears
cytokine release lead to inflammation which causes…
monocytes and neutrophils to be activated vasodilation increased vascular permeability mast cell degranulation clotting system activated kinin system activated
what is the acute phase response
systemic response using interleukins
function of interleukin 1
sent to brain to produce fever (pathogens have poor tolerance), poor appetite & lethargy to conserve energy for fighting infection
function of interleukin 2 & 12
activates natural killer cells
function of interleukin 6
sent to liver to activate/produce acute phase proteins (opsonins)
function of opsonins
extracellular acute phase protein
attach to pathogens, making them more recognisable to macrophages/inducing phagocytosis
eg. c-reactive protein, measured clinically as marker of inflam/infection
function of interleukin 8
recruits and activates neutrophils
function of tumour necrosis factor
used in acute phase response multifunctional cytokine important roles in diverse cellular events such as cell survival, proliferation, differentiation, and death fights infection (does all of the interleukin roles itself)
describe phagocytosis
macrophages recognise PAMPs using toll-like receptors
engulf pathogen into a phagosome
lysosome in cell fuses with phagosome
lysosome releases digestive enzymes and breaks down pathogen
releases cytokines to trigger inflammation
lectin pathway trigger
directly by pathogens
alternative pathway trigger
directly by pathogens
classical pathway trigger
antibody-antigen complex
describe complement system
proteins activate each other in cascade
enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen’s cell membrane
describe specific immune response
- dendritic cell displays antigen on HLA class II molecule to CD4 cells in lymphatic tissue which proliferate into T helper cells
- THC present antigen on HLA class I molecule (recognised by HLA class I molecule) and release cytokines
- cytokines encourage proliferation/differentiation of CD8 into cytotoxic T cells and B cells to become plasma and memory cells
what are cytotoxic cells responsible for
killing virally infected cells via spraying cytokines = cell lysis OR FAS pathway = self destruction
what are cytotoxic cells responsible for
killing virally infected cells T cell receptor bind with HLA class I holding antigen on infected cell either spraying cytokines = cell lysis OR FAS pathway = self destruction
