Flashcards in ToB 18 Innate and Adaptive Immunity Deck (56)
What is the first barrier of the human body against infection?
What is a 'cytokine'?
A protein secreted by one cell type, which can alter the behaviour of other cells
What is a 'chemokine'?
A type of cytokine (a protein), which attracts other cells, initiating chemotaxis.
Some pathogens can damage epithelial cells to gain entry to host. How will this epithelial cell react once damaged?
Becomes 'activated', releasing chemokines and other cytokines
What is an 'activated epithelial cell'?
Damaged epithelial cell, which responds by secreting chemokines and other cytokines
How do epithelial cytokines affect capillary mesothelium?
Increase the permeability
Why is it important that epithelial cytokines increase the permeability of capillary mesothelium?
Allows immune cells to migrate from the blood vessels to the site of damage
What is 'oponisation'?
The coating of a microorganism by antibodies or complement, to allow phagocytes to recognise it as foreign, stimulating/enhancing phagocytosis.
What are the 5 components of inflammation?
5) Loss of function
Is a lysozyme part of the innate or adaptive immune response?
Is a lymphocyte part of the innate or adaptive immune response?
Is a macrophage part of the innate or adaptive immune response?
What type of immune response is non-specific and has no memory?
Innate immune response
What type of immune response is enhanced by a second exposure?
Adaptive immune response
Name the main 6 cell types necessary for an innate immune response:
1) Mast cells
6) Natural Killer cells
How does an eosinophil differ from a neutrophil in a histology slide stained with H&E?
The granules within eosinophil cytoplasm take up the eosin stain so appear red, while those in neutrophils take up haematoxylin so appear purple
How can you distinguish between a neutrophil and a lymphocyte?
Neutrophils have a multiple-lobed nucleus, lymphocytes do not.
Neutrophil's are also larger than lymphocytes.
What is the smallest type of leukocyte?
What is the largest type of leukocyte?
Name the 3 granular leukocytes:
What is the most common type of leukocyte?
What are the 2 types of phagocytes?
The active engulfment of particles into a phagosome.
What is required by a phagosome for digestion of the engulfed material?
What is the 1st event of an inflammatory response?
Arrival of neutrophils
Type of immune cell (WBC) which contains granules in its cytoplasm, which contain enzymes for immune response.
What allows neutrophils to recognise bacteria and initiate phagocytosis?
Neutrophils express many different receptors specific to different bacteria types, which bind to bacteria and allow the neutrophils to engulf and digest them.
What is the primary type of profession antigen presenting cell?
What is the function of antigen-presentation?
To allow T-lymphocytes to recognise a foreign pathogen, and to stimulate an adaptive immune response
Which type of leukocyte cannot recognise foreign pathogens?
What is the complement system:
A part of the immune system that marks pathogens for destruction by covalently binding to their surface.
How do natural killer cells induce apoptosis of virus-infected cells?
Create pores in target cells
Pump proteases through these pores into the cell
How are T-lymphocytes distinguished from B-lymphocytes and NK cells?
Only T-lymphocytes express T-cell receptors (TCRs)
People lacking NK cells are most at risk of what kind of infection?
How do most cells activate NK cells if they become infected with a virus?
Release IFα and/or IFβ (interferons) if they become infected, which activate NK cells
What type of immune cell produces the earliest response to a viral infection?
Natural Killer cells
How does a viral infection stimulate NK cell activation?
Virus infects an epithelial cell,
causing it to become activated and release cytokines
these induce proliferation and activation of NK cells
What 2 proteins are secreted by the innate immune system to deprive micro-organisms of iron?
How does the secretion of Transferrin cause micro-organisms to be deprived of iron?
Transferrin tightly binds to iron.
What is the antimicrobial enzyme found in sweat, tears, and saliva that can specifically break down peptidoglycan?
What is the enzyme present in tears which breaks down peptidoglycan?
What are the components of the complement system?
C1 - C9
Which component of the complement system binds to the surface of microbes and marks them for destruction?
Which components of the complement system recruit inflammatory cells?
Which component of the complement system forms a pore in the microbial cell membrane?
Which are the most essential components of the complement system?
Molecule that elicits a specific immune response when introduced into the body
Which type of lymphocyte matures in the Thymus gland?
Which type of lymphocyte matures in the bone marrow?
Name the 2 types of T-lymphocytes:
1) T helper cells (Th)
2) Cytotoxic T lymphocytes (CTL)
Which type of B-lymphocyte produces antibodies against an antigenic stimulus?
What is the difference between the antigen receptors expressed by B and T lymphocytes?
B cell antigen receptor is MEMBRANE BOUND
T cell antigen receptor is not, is a DISTINCT MOLECULE
How many different antigen receptors are expressed by one lymphocyte?
One, they are very specific
What are the 3 ways in which antibodies protect the host from infection?
1) Prevent bacterial adherence to epithelial cell
2) Opsonisation, promoting phagocytosis
3) Activates the complement system
What prevents our normal gut microflora from entering our epithelial cells?
Antibodies (IgA) cover the bacteria preventing bacterial adherence to epithelial cells