Adaptive immunity- extracellular Flashcards
which cell act was a bridge between the immune and adaptive immune system
antigen presenting cells
if naive T cells and pathogen meet
no response
only way T cells can be activated is by
antigen presenting elsl
APCS
phagocytose and process the microbe and present it to the Naïve T cell so they can recognise pathogen/tumour cell
naive T cell
T cell that have no previously encountered the antigen
effector T cell
T cells that have previously encountered the antigen are capable of performing the effector functions during an immune response
Antigen presenting cells role
- Sense the pathogen
- Capture pathogen
- Process pathogen
- Present the pathogen to T cells
name 4 APC
dendritic cells
langerhans
macrophages
B cells
dendritic cells and langerhans (dendritic cell specialised for the skin) present the pathogen to ……………. and have what function
present to naive T cells
Function: T cell response against most pathogens
macrophages and B cells present the pathogen to …………….
present to effector T cells
function of macrophages
phagocytic activities
function ofB cells
antibody response (humeral)
APC are found in strategic locations
- Mucosal membrane (gut, lung)
o Mucosal associated lymphoid tissue (MALT) - Skin (Langerhans cells)
o Skin associated lymphoid tissue) - Blood (plasmacytoid cells)
- Lymph nodes (follicular dendritic cells)
- Spleen
pathogen capture method of APC
- Phagocytosis (whole microbe)
- Micropinocytosis (soluble particles)
2 types of microbes
- Extracellular
o Fungal
o protozoa
o Most bacteria - Intracellular
o Virus
o TB
o Cancer
PRRS recongise
intracellular and extracellular pathogens PAMPs
TLR recognise extracellular pathogens
TLR1,2,6,4,5,11
- TLR4- Neisseria meningitidis- sepsis
TLR recognise intracellular pathogens
TLR3,7,8,9
how do APC activate the adaptive immune system
- Macrophages and APC recognise pathogen
- APC use lymphatics to get to lymphoid tissue
- APC presents to T cells
Major histocompatibility complexes (MHC) molecules are a type of
human leukocyte antigen
HLA
human body version of MHC
- how pathogens are presented to naive T cells
MHC I
- Expressed on all nucleated cells
- CD8 cytotoxic T cells
- Kill intracellular pathogens
• Virus’
• TB
• Cancers
MHC II
- Expressed on APCs, dendritic cells, macrophages and B cells
- CD4 T helper cells
• Fungal
• Bacteria
• Parasitic
key features of MHC molecules
- Co-dominant expression
o Both MHC class I and II parental molecules are co-expressed in each individuals (6 of each class) - Polymorphic genes (diff alleles)
o Different individuals present and respond to different microbes