Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
103 Cards in this Set
- Front
- Back
What are the two branches of the immune system? |
Innate and Adaptive |
|
State two major differences between the innate and adaptive response. |
The adaptive response is more specific |
|
What are the differences between the innate and adaptive response regarding effector cells? |
Innate: Phagocytes (macrophages and neutrophils), NK cells, eosinophils, mast cells |
|
What are the differences between the innate and adaptive response regarding effector molecules? |
Innate: lysozyme, complement proteins, interferons, lactoferrin and defensins |
|
What are mechanical barriers to infection? |
Tight junctions between epithelial cells |
|
What are chemical barriers to infection? |
Acidity of the stomach acid |
|
What is meant by 'microbiological' barriers to infection? |
Bacteria having a symbiotic relationship |
|
What is the structure of macrophages, and how do they circulate in the blood? |
Mononuclear (one nucleus) |
|
Where are macrophages found? |
Within tissues |
|
What are 3 properties/characteristics of neutrophils? |
They have a multi-nucleus (polymorphonuclear) with granules. |
|
What are the properties/characteristics of eosinophils? |
Bi-lobed nucleus |
|
What are the properties of mast cells? |
Found alongside blood vessels below epithelial cells |
|
What are the properties of NK cells? |
Large cytotoxic cells involved in killing cells infected with a virus |
|
What are the 4 stages of the innate response? |
1. Adherence of bacteria to epithelium |
|
What are the 3 stages of the adaptive response? |
1. After around 96 hours the bacteria will enter the lymphatic system, tothe lymph nodes |
|
What are the functions of the two major lymphocytes? |
- B cells mature into plasma cells which release soluble antibodies |
|
Describe the function of Toll-Like Receptors (TLRs), giving one named example. |
- TLRs recognise sequences on non-self cells known as pathogen-associated molecular patterns (PAMPs) |
|
What is Phagocytosis? |
1. An activated macrophage recognises a pathogen, such as a bacterium |
|
What is opsonisation? |
- The process of altering the surface of a pathogen to facilitate phagocytosis |
|
Describe the process of opsonisation. |
Hydrolysis of the complement protein C3 into C3a and C3b |
|
What is C3 convertase? |
C3b,Bb |
|
Which complement proteins make up the membrane attack complex? |
C5b, C6, C7, C8 and C9 |
|
What function do C3a and C5a have? |
Activation of mast cells to produce histamine |
|
What is the function of the membrane attack complex? |
The membrane attack complex is a channel that forms on a microbial cell membrane, which results in cell lysis due to influx of extracellular fluid |
|
What are the functions of TNF-α? |
- Recruitment of IL-8 (a chemoattractant) and E-Selectin (adhesion molecules) during neutrophil recruitment |
|
What are functions of IL-1? |
- Endogenous pyrogen (causes an increase in body temperature to stop bacteria replication) |
|
What are the functions of IL-8? |
- IL-8 is a potent chemoattractant/chemokine involved in many processes, including the recruitment of neutrophils at infection sites |
|
What are the functions of IL-6 and IL-12? |
- Endogenous pyrogen - Increases antibody production by B Cells |
|
What are the symptoms of inflammation? |
Rubor, calor, dolor, tumor |
|
What is the first stage of neutrophil recruitment? |
Rolling Adhesion- |
|
What is the second stage of neutrophil recruitment? |
Tight Adhesion- |
|
What is the third stage of neutrophil recruitment? |
Diapedesis- |
|
What is the fourth stage of neutrophil recruitment? |
Migration- |
|
Which antibody isotype forms pentamers around a J chain in the secreted form? |
IgM |
|
Which antibody isotype is the most abundant in the blood? |
IgG |
|
Which antibody isotype is mostly found in mucosal secretions? |
IgA |
|
Which antibody isotype is mostly associated with the allergic response, and which receptor will it bind to on mast cells? |
IgE, FcεRI |
|
A previously healthy 8-year-old boy is infected with an upper respiratory tract virus for the first time. During the first few hours of infection, what will occur? |
The innate immune system responds rapidly to the viral infection and keeps the viral infection under control. |
|
What is a unique property of the adaptive immune system? |
Highly diverse repertoire of specificities for antigens |
|
A standard treatment of animal bite victims, when there is a possibility that the animal was infected with the rabies virus, is administration of human immunoglobulin preparations containing anti rabies virus antibodies. Which type of immunity would be established by this treatment? |
Passive humoral immunity (antibody mediated immunity) |
|
At 15 months of age, a child received a measles-mumps-rubella vaccine (MMR). At age 22, she is living with a family in Mexico that has not been vaccinated and she is exposed to measles. Despite the exposure, she does not become infected. Which of the following properties of the adaptive immune system is best illustrated by this scenario? |
Memory |
|
A vaccine administered in the autumn of one year may protect against the prevalent strain of influenza virus that originated in Hong Kong that same year, but it will not protect against another strain of influenza virus that originated in Russia. This phenomenon illustrates which property of the adaptive immune system? |
Specificity |
|
In which phagocyte(s) are granules found? |
Neutrophils and eosinophils |
|
Name the substances stored in azurophilic/primary granules. |
Cathepsin G |
|
Name the substances stores in specific/secondary granules. |
Lactoferrin |
|
Name the substances stored in tertiary granules. |
Gelatinase |
|
Describe the process in which the antimicrobial substance is produced within the neutrophil. |
1. NADPH Oxidase transfers electrons to molecular oxygen generating superoxide free radicals |
|
Where are T-cells produced, and where do they mature? |
Produced in bone marrow, mature in thymus |
|
Where are B-cells produced, and where do they mature? |
Produced in bone marrow, mature in bone marrow |
|
What do activated B-cells differentiate in to? |
Memory cells and plasma cells |
|
What do activated T-cells differentiate in to? |
CD4+ helper T cells |
|
State the postulates of the clonal selection hypothesis. |
1. Each lymphocyte has a specific receptor which recognises a specific antigen 4. The cells that differentiate from the activated lymphocyte will be identical to the parent cell, and have the identical specificity. |
|
Howis the diversity of lymphocyte antigen receptors generated? |
By rearrangement of gene segments coding for T-cell receptors on T-cells and surface immunoglobulins on B-cells |
|
What Fc antibody isotype does the anti-RhD antigen have? |
IgG |
|
How long after sensitisation to an antigen does the effector phase occur? |
7-10 days |
|
Where are MHC I and MHC II found? |
MHC I is found on all cells (except RBC) and binds to CD8+ |
|
Describe the process of T-cell activation. |
- MHC II on the APC will present an antigen to the TCR, which will recognise it as foreign |
|
What is the structure of the TCR? |
- There are two distinct chains - alpha and beta |
|
Describe the process of antigen processing and presentation. |
1. Lysosomes in macrophages degrades bacteria producing bacterial peptide fragments |
|
Describe the effect of TNF-α and IFN-γ on activated macrophages. |
TNF-α and IFN-γ are released from activated CD4+ Th1 helper cells and act on activated macrophages increasing the efficiency of bacterial killing |
|
Describe the effect of IL-4, IL-5 and IL-6 on B-cells. |
IL-4, IL-5 and IL-6 are released from activated CD4+ Th2 cells and act naiive B-cells, causing them to become plasma cells and increase antibody synthesis. |
|
Describe how CD8+ cells kill viruses. |
When MHC I binds to the TCR on CD8+ cytotoxic cells, the CD8+ cell will release perforin and granzymes which induce programmed cell death (apoptosis). |
|
Describe how the activation signal in T-cells is turned off. |
- When T-cells become activated, they begin to express CTLA-4 which has a higher affinity for B7 than CD28 |
|
What are the 3 most important functions of macrophages? |
1. Phagocytosis of opsonised bacteria |
|
What are the 3 most important functions of activated T-cells? |
1. Activation of macrophages by TNF-α and IFN-γby CD4+ Th1 cells |
|
Which portions of the antibody make up the variable region? |
2x Vl light chains |
|
Which portions of the antibody make up the constant (Fc) region? |
2x Cl light chains |
|
What are the 2 halves of the antibody bonded by? |
Disulfide bonds |
|
Describe how activated T-cells help to activate naiive B-cells. |
- CD4+ Th2 helper cells recognise antigen on B-cell MHC II molecule and synthesise cytokines |
|
Describe how IgA moves across epithelia into external secretions. |
- IgA movement across epithelial cells is known as transcytosis |
|
State the 3 inhibitory/neutralisation functions of antibodies. |
1. Inhibition of bacterial cells to host cells |
|
State the 2 stimulatory functions of antibodies. |
1. Opsonisation of bacteria for quicker and more efficient phagocytosis |
|
What is the classical pathway of complement activation? |
- IgG or IgM in the blood bind to pathogens and activate the classicalpathway |
|
What is the lectin pathway of complement activation? |
When lectins bind to carbohydrate molecules on bacterial/viral cell surfaces |
|
What is the alternate pathway of complement activation? |
- Spontaneously activated complement bindsto the surface of the pathogen, where it forms a C3 convertase (C3b,Bb) that isstabilised by properdin (factor P) on the pathogen topromote the further formation of C3b |
|
Name the functions of complement proteins. |
- Recruitment of inflammatory cells by C3a and C5a |
|
What is antibody-dependent cell-mediated cytotoxicity? |
- The destruction of antibody coated target cells is called antibody-dependent cell-mediated cytotoxicity and is triggered when antibody bound to the cell surface interacts with Fcγ IgG receptors on the NK cell |
|
What is the mechanism of lysozyme? |
- Lysozyme are glycoside hydrolyses which catalyse the breakdown of bacterial cell walls |
|
What is the mechanism of definsins? |
- Small cationic proteins |
|
What is the mechanism of lactoferrin? |
- Lactoferrin can be found in the secondary granules of neutrophils |
|
Name the type 1 interferon(s). |
IFN-α |
|
Name the type 2 interferon(s). |
IFN-γ |
|
State the names of all 3 chemoattractant molecules |
- IL-8 (interleukin - 8) |
|
In antigen presenting cells (APCs) where is MHC II produced and stored? |
- Produced in ER (endoplasmic reticulum) |
|
How are eosinophils activated? |
- Parasites such as tapeworms become covered with specific IgE and IgA antibodies |
|
What happens in the early phase of allergen response? |
- There is degranulation and release of histamineacting on H1 receptors, which causes vasodilation and increases vascular permeabilityand bronchial smooth muscle contraction (bronchoconstriction) |
|
What happens in the late phase of allergen response? |
- Mastcells synthesise and release cytokines that stimulate an inflammatory responseby T-cells and eosinophils |
|
What is type I hypersensitivity? |
- the 'wheal and flare' response |
|
What are the symptoms of an allergic reaction? |
Itch, local swelling, hypotension, wheezing, diarrhoea |
|
Anaphylaxis Treatments: |
- Epipen (adrenaline injection) |
|
Which antigen(s) will people with blood type A have on their erythrocytes? |
Type A |
|
Which antigen(s) will people with blood type B have on their erythrocytes? |
Type B |
|
Which antigen(s) will people with blood type AB have on their erythrocytes? |
Both Type A and Type B |
|
Which antigen(s) will people with blood type O have on their erythrocytes? |
Neither antigen |
|
Which antibody/antibodies will people with blood type A contain in their plasma? |
Anti-B |
|
Which antibody/antibodies will people with blood type B contain in their plasma? |
Anti-A |
|
Which antibody/antibodies will people with blood type AB contain in their plasma? |
Neither antibody |
|
Which antibody/antibodies will people with blood type O contain in their plasma? |
Both Anti-A and Anti-B |
|
Which blood group is considered to be the universal donor? |
Type O |
|
Which blood group is considered to be the universal recipient? |
Type AB |
|
What happens if there is transfusion of incompatible blood? |
- Antibodies to incompatible blood are usually of the IgM isotype andcause agglutination, complement activation and intravascular hemolysis with release of hemoglobin and subsequent kidney damage |
|
What is haemolytic disease of the newborn? |
-Peoplewhose RBCs have the RhDantigen are Rh+ and peoplewho lack the RhDantigen are Rh- |
|
How can haemolytic disease of the newborn be treated? |
-Givingthe Rh- mother preformed anti-RhD antibodies immediately after thebirth of the first child |