1 - Intro to immunology Flashcards
What are the roles of the immune system?
- protection of host from pathogenic microorganisms
- distinguishing self from non-self
- distinguishing self from abnormal self (surveillance and clearance of abnormal (cancer cells)
give an example of immunodeficiency
SCID (severe combined immunodeficiency)
What is the generation time of bacteria and viruses?
bacteria - minutes
viruses - hours
What is immunopathology?
the balance between clearing the pathogen and causing collateral damage (to the host)
Gives examples of PAMPs and DAMPs
PAMPS
e.g. bacterial cell wall components- flagella, LPS, peptidoglycan- dsRNA in cytoplasm, viral RNA
PRR: Toll-like receptors
DAMPS
e.g. high extracellular ATP, monosodium urate, reactive oxygen species, DNA
ECM—> fragments of aggrecan, fibronectin, collagen, hyaluronan
What is an acute phase inflammatory response a response to?
(an acute response) to tissue damage
What happens in an acute phase inflammatory response?
activation of IL1
followed by production of acute phase proteins by the liver
Define acute phase proteins
a class of plasma proteins whose plasm concentrations increaser (positive acute phase proteins) or decrease (negative acute phase proteins) in response to inflammation
What are cytokines?
large family of soluble molecules
diffuse into nearby cells, bind to specific receptors and alter the pathogen gene expression
important in the proliferation of lymphocytes
transmit info between cells
Which cells are granulocytes?
BASOPHILS - least abundant type of leukocyte NEUTROPHILS - multi-lobed nucleus - phagocytic EOSINPHILS - bi-lobed nucleus - important in response to parasites
Define antigen
molecules that are recognised and bound by lymphocyte (NOT necessarily foreign molecules)
Define an antibody
an immunoglobulin molecule in the blood and body fluids which binds specifically to an antigen
What is an immunogen?
an antigen that initiates an immune response
What is an epitope?
the part of an antigen that an antibody binds to
What types of cells are lymphocytes?
How are the subtypes distinguished?
granular leukocytes
involved in the acquired immune system
distinguished by CD markers
What are B-cell antigen receptors?
membrane bound antibodies
bind INTACT antigens
What are T-cell antigen receptors?
(have 2 protein chains- alpha and beta)
only bind digested/processed antigen fragments
What complex does TCR recognise? (to recognise an antigen)
a complex of antigen peptide and HLA (MHC) complex
What are MHCs and what is their function?
Major Histocompatibility Complex
they are locales that present processed antigens to T lymphocytes)
What is MHC known as in humans?
HLA (human leukocyte antigen)
What are the 2 strategies used by the immune system to recognise danger?
Give the main differences
STRATEGY 1 - germ-line encoded - hundreds of receptors - use PRRs (pattern recognition receptors) STRATEGY 2 - random recombination of gene segments - thousands of receptors (wider variety) - use antigen specific receptors on lymphocytes
B-cells receptors bind ______
antigens
T-cell receptors bind ______
(processed) antigen fragments present at cell surfaces
Compare the innate and adaptive immune system
- fast (minutes/hours) vs slow (days/weeks)
- germine encoded vs random recombination
- limited specificity (small range of PAMPs/DAMPs) vs unlimited specificity
- independent of previous exposure vs dependent on previous exposure
- no memory vs memory
What cells/molecules use the cellular and humoral response?
cellular - T and B cells
humoral - antibodies
Name the 3 types of cells used in innate immunity
neutrophils
macrophages
eosinophils
Name the 3 molecules used in the innate immune system
acute-phase proteins
complement
cytokines
Name the 2 types of cells used in adaptive immunity
T and B lymphocytes
Name 2 soluble factors used in adaptive immunity
cytokines
antibodies
Name the 3 types of cells that partake in both types of immunity
basophils/mast cells
dendritic cells
NK cells
When clonal selection occurs, how is the infection cleared?
- cytotoxic T-cells can kill infected cells
- antibodies being to the antigens
- —-> this triggers clearance by phagocytes - OPSONISATION
- —–> can inactivate toxins, agglutinate and activate the complement pathway and NK cells
