Immunology Flashcards
What are the natural barriers of the innate response?
Physical barrier Physiological barrier Sebaceous secretions Mucous Commensal bacteria
What are the main cells of the adaptive immune response?
B and T cells
What are the differences between the innate and adaptive response?
Innate is rapid, adaptive is slow
Innate has no memory, adaptive does
Innate is non-specific, adaptive is specific
Innate uses PAMPs and PRRs and adaptive uses antigens and antibodies
What are the cells of the innate system?
Macrophages NK cells Neutrophils Basophils Eosinophils Dendritic cells Mast cells Complement proteins CRP
What do PAMP and PRR stand for?
Pathogen Associated Molecular Patterns
Pattern Recognition Receptors
Which cell has a kidney bean nucleus?
Macrophages
Where do macrophages reside?
Exposed epithelium - lungs, skin, intestine
What is the function of macrophages?
Phagocytic killing
Also use ROS induced by interferon gamma
Clear away debris
TNFa production
What are different names for macrophages?
Kupffer cells in liver
Alveolar macrophages in lungs
What is the appearance of NK cells?
Granular
How do NK cells kill?
Degranulation, release of perforin
What is the function of NK cells?
Kill abnormal/infected cells
Produce interferon gamma
What is the function of neutrophils?
Circulate in blood stream and migrate to infected areas via transendothelial migration
Kill by phagocytosis, degranulation, NETs
How do neutrophils migrate to an area?
Chemokines cause blood vessels to becomes leaky
Blood stasis cause WBC marginalisation, rolling and adhesions via ICAM and VCAM
What is chemotaxis?
the movement of cells due to a chemical gradient
What does raised neutrophils in the blood suggest?
Acute inflammation
What is the most common WBC?
Neutrophil
Describe the nucleus of neutrophils?
Multi-lobed
Neutrophils are short-lived, true or false?
True
Describe the appearance of basophils?
Bilobed nucleus
Stained blue
Granules
What is the function of basophils?
Act as effector cells in allergic reaction
What is the function of eosinophils?
Allergy
Describe the appearance of eosinophils?
Bilobed nucleus
Stained red
What is the example of antigen presenting cells?
Dendritic cells
What is the function of dendritic cells?
Phagocytose pathogens and then present the antigens to T cells via MHC class II molecules
What is the function of mast cells?
Allergy
Kill large antibody-coated parasites that can’t be phagocytosed
Release histamine, heparin - degranulation
What is opsonisation?
The coating of pathogens by soluble factors (opsonins) that enhance phagocytosis
What are examples of opsonins?
C3b
CRP
IgG
IgM
Where are complement proteins produced?
Liver
What are the 3 pathways of complement system activation?
Classical pathway
MBL pathway
Alternative pathway
What is the classical pathway?
IgG and IgM activate the complement cascade
What are the outcomes of the complement cascade?
Opsonisation enhances phagocytosis
MAC allow pathogen killing
C3a and C5a cause acute inflammation
What is the alternative pathway?
C3b, produced by C3, activates C3 again
What are the effects of acute inflammation?
Swelling Dolor - pain Calor - heat Rubor - redness Functio laesa - loss of function
Where do B cells mature?
Bone marrow
How and where do lymphocytes usually circulate?
Found the primary lymphatic tissue in inactive form
What activates B and T cells?
Antigen presentation
What needs to happen for B cell activation?
Antigens present and signals from T helper cells
What happens after B cell activation?
They proliferate and differentiate into plasma cells
Which region of the antibody do antigens bind to?
Fc region
What is the first immunoglobin produced?
IgM
What is the shape of IgM?
Pentametric
What is the function of IgM?
B cell activation and complement system activation through the classical pathway
What is the most abundant imunoglobin?
IgG
What is the shape of IgG?
Monometric
What are the functions of IgG?
Foetal immunity Complement activation NK cell activation Opsonisation Agglutination
What is agglutination?
The clumping of antigens together to enhance phagocytosis
Which immunoglobin is important in neonatal immunity, and when does this take effect?
IgA
6 months after birth
What is the other function of IgA
Secretions
What is the function fo IgE?
Allergy
What is the function of IgD?
B cell activation
Where do T cells mature?
Thymus
What are the types of T cell?
CD4+ helper cells
CD8+ cytotoxic cells
Regulatory T cells
Memory T cells
What is the function of CD4+ T cells?
Activate B cells and stimulate proliferation of memory B cells
What is the function of CD8+ T cells?
Kill infected cells via perforin/granzymes/granulysin
What is the function of regulatory T cells?
Lymphocyte suppression
How are antigens presented by MHC molecules?
Antigens are presented by MHC (major histocompatibility complex)
What is the difference between Th1 cells and Tfh cells?
Th1 - help macrophages
Tfh - help B cells
Which cells need MHC molecules?
T cells
What is the function of MHC?
Display peptide antigens to TCR on T cells
What is the difference between class 1 and 2 MHC?
Class 1 - present on all nucleated cells, present to CD8+ killer T cells
Class 2 - present only on APC, present to CD4+ helper T cells
What is type 1 hypersensitivity, and what is an example?
IgE mediated
Mast cells and eosinophils
Happens in seconds
Allergy
What is type 2 hypersensitivity, and what is an example?
IgM and IgG NK cells Antigen bound to cell surface Onset is seconds to hours Goodpasture's
What is type 3 hypersensitivity, and what is an example?
Immune complex mediated Antibody to soluble antigen IgG, neutrophils Onset is in hours Acute hypersensitivity pneumonitis
What is type 4 hypersensitivity, and what is an example?
Delayed hypersensitivity
Macrophages, T cells
Onset is in days
Chronic hypersensitivity pneumonitis, TB, sarcoiosis
