Immunology Flashcards
The function of the immune system is to…..
Prevent and control infections, eliminate pathogens and their harmful products.
The immune system is characterized by layering and redundancy. WTF does that mean?
Layering- Multiple layers of protection.
Redundancy- A single pathogen can be fought by the immune system in multiple ways.
What are the two major types of immunity?
Innate, Adaptive/acquired
Pathogen motif receptors and Antigen-specific receptors are used to tell the difference between….
Self and Non Self
Blood is an important component of the immune system, it contains….
Leukocytes, Lymphocytes, Clotting Factors, Complement, Antibodies
The immune response consists of two parts, ____ and recruitment of effector mechanisms.
Recognition of pathogens
What do Lymph Nodes do?
Filter interstitial fluids, removes antigens and makes them available to B/T cells, place for B cells to make antibodies.
Which immune system is present at birth, and is always present at basal levels?
Innate immunity
T or F. The innate immunity provides immunological memory.
False. Adaptive/acquired immunity
T Lymphocytes have _____ that recognize the pathogen participate in the adaptive response.
Receptors
What are the two categories of adaptive immunity?
Humoral, Cell Mediated
What cellular/noncellular components make up innate immunity?
Leukocyte, Biochemical constituents (enzymes), anatomical/physical barriers, proteins (complement, cytokines, chemokines), inflammation
What are the 3 properties that make Adaptive Immunity so effective and protective?
Diversity, Specificity, and Memory
_____ respond to a single foreign antigen and become activated only when that antigen is encountered.
Lymphocytes
Name the 3 states of a mature Lymphocyte.
Naive, Effector, Memory
Name 3 different Leukocytes/Granulocytes.
Basophils, Eosinophils, Mast Cells
Antigen Presenting Cells engulf pathogens and present them to T Cells. Name 3 types of APCs.
Dendritic cells, macrophages, B cells
_____are produced by activated B-Cells.
Antibodies
_____are mainly produced by activated immune cells like T-cells, Macrophages, and NK cells.
Cytokines
This subset of the adaptive immunity protects against EXTRAcellular pathogens.
Humoral Immunity
T or F? CD4 TH1 is found in the Humoral Immunity.
False. CD4 TH2
This subset of the adaptive immunity protects against INTRAcellular pathogens.
Cell Mediated Immunity
Phagocytes process and present enulfed antigens to T Helper cells to activate what?
Adaptive Immunity
The production and secretion of what results in the upregulation of MHC class I molecules for more productive antigen presentation to cytotoxic T cells?
Interferon (IFN)
_____on the surface of an antigen can enhance B cell activities.
Complement Proteins
Cytokines upregulate ______ molecules on phagocytes for better antigen presentation to T Helper cells.
MHC class II
What recognizes LPS and sends a signal to activate NF-kappaB which leads to production of cytokines and the upregulation of molecules important for B/T cell activation?
TLR 4
Name 3 ways the adaptive immunity activates/regulates the innate immunity?
T cells produce cytokines that enhance phagocytosis and oxidative burst.
Antibodies bound to the surface of an antigen increase their uptake by phagocytes (opsonization)
Cytokines produced by activated CD4 T cells (T 1 Helper cells) activate macrophages and upregulate expression of Fc receptors on macrophages, NK cells, and neutrophils.
The ____branch of the adaptive immunity has both T helper 1 and T helper 2 cells.
Humoral
What is the single effector function of B cells?
To produce antibodies
What is a membrane form of an antibody that plays an important role in B cell activation?
B Cell Receptor (BCR)
What is the role of soluble (secreted antibodies)?
Recognize and bind extracellular pathogens and their products and deliver them to phagocytes for removal
(edited by KH)
What allows antibodies to share common effector functions?
Conserved sequences.
T or F? Antibodies can kill and remove pathogens by themselves.
False.
The specificity of an antibody is attributed to to the _____ region.
Variable.
The biological activity of an antibody is determined by the _____ region.
Constant.
Do constant regions of antibodies differ between different isotypes?
Yes.
How many light and heavy chains does an antibody molecule have?
2 Heavy, 2 Light.
The two L chains do NOT interact with each other.
……
What type of bond connects each L chain to an H chain?
Interchain disulfide bonds.
What type of bond connects the two H chains to one another?
Interchain disulfide bonds.
How heavy are heavy chains?
50,000 Da
How heavy are light chains?
25,000 Da
The variable region of the L and H chains determine specificity. Where is the variable region?
The N-Terminal.
Why do different antibody isotypes have different functions?
The constant regions.
The constant region of the heavy chain is subdivided into __domains.
Three
The constant region of the light chain is subdivided into __ domains.
One
Which Immunoglobulins have 4 CH domains?
IgM, IgE
The antibody molecule can be divided into functional regions, they are……
Fab- Fraction antigen binding
Fc- Fraction crystallizable
Hinge- Present in IgG, IgA, and IgD (all have 3 CH domains)
What enzyme is capable of breaking an antibody into 2 Fab and 1 Fc?
Papain
This region of an antibody retains the ability to bind antigen, consists of the VH, VL, CL, and CH1 domains. Each full antibody also contains TWO of these fragments.
Fab
What two distinct functions are served by the Fc region?
Delivers the antibody to specific anatomical sites (she spells it sights in her notes….?)
Assists in Opsonization by binding to Fc receptors on immune cells that phagocytose the attached antigen.
This portion of the antibody molecule contains CH2, CH3, and CH4 (if it exists), and most of the hinge.
Fc
How many fragments of Fc per antibody?
One
If Pepsin is used to generate an F(ab)2, which portion was NOT generated?
Fc. It is cleaved BELOW the hinge.
What AA residues primarily make up the hinge region?
Pro, Ser, Thr
What allows the 2 Fab arms to open/close to accommodate binding to 2 epitopes?
The Hinge region
The hinge region is found between what two domains?
CH1 and CH2
T or F? IgG, IgA, and IgD all have 3 CH regions, which means they DO NOT have a hinge region.
False, they do! Seriously. They do.
What two fragments retain the ability to bind antigen?
Fab and F(ab)2
What is the small glycoprotein associated with POLYMERIC IgA and IgM (Not hexameric IgM)?
J chain
How many J chains per antibody?
One
What is the function of the J chain?
Polymerization and interaction with the poly-Ig receptor (transports antibodies from the basal side of the epithelium onto the luminal side of the mucosal surface)
What type of bonds give antibody molecules their globular shape and separate the domains of each chain?
Intra chain S-S Bonds
Which portions of the L chain interact with what portions of the H chain in the Fab portion?
VL with VH
CL with CH1.
Within the Fc portion, the CH3 domains interact, but the two _____ domains do not.
CH2
The V region is subdivided into what two regions?
Hypervariable and framework regions.
What region of the Variable region actually makes contact with the epitope?
Hypervariable
The hypervariable region is present in both the VL and VH regions. True or false: There are 3 different stretches of 8-11 AAs in both regions.
True
Hypervariable regions are also known as……
Complementarity-Determining Regions.
How many CDRs per monomeric antibody molecule?
12 (3 from each L chain and 3 from each H chain)
The remaining 80ish AAs of the V region between CDRs are called…..
Framework Regions
How many Framework regions in each V region?
Four
What are the two types of light chains?
Kappa and Lamdba
T or F? Both L chains in a given antibody molecule are NOT the same.
False. They are identical (both Kappa or Lambda)
T or F? There is no known effector function associated with the L chain.
True.
What chain determines the class/isotype and the effector function of the antibody?
H-Chain
What are the 5 major H chain isotypes?
IgA, IgD, IgE, IgG, IgM
IgG is subdivided into how many classes in humans?
Four. IgG1, IgG2….
IgA is subdivided into how many classes in humans?
Two. IgA1, IgA2
T or F. Since Isotype is determined by the C region, it has nothing to do with antigen specificity.
True. Specificity is controlled by the V region.
What is the first isotype secreted when B cells are activated by T cells?
IgM
IgM is made almost exclusively as a _____, but has been found as a hexamer.
Pentamer.
What is the most efficient isotype for activating the classical complement pathway?
IgM
What is the only isotype made by a fetus?
IgM
What is the half life of IgM?
5 days
If you have an IgA deficiency, how does that affect IgM secretion?
IgM secretion increases.
What is the major source of IgM in saliva?
Gengival cervicular fluid
What is the half life of IgG?
23 days. Except for IgG3, which is 7 days.
What isotype is the most abundant in tissues and serum?
IgG
What is the only isotype that crosses the placenta?
IgG (IgG1>IgG3>IgG2>IgG4)
Which isotype is bound Fc receptors and can participate in ADCC?
IgG
When does IgG production start in infants?
4-6 months
The small size of IgG allows it to do what?
Cross the vasculature and endothelium.
Which subtype of IgG is found in about 50% of the Caucasian population?
IgG2
How many subclasses of IgA are in humans?
Two
WHat is the half life of IgA?
Five days
What is special about dimeric IgA + Lysozyme?
It can kill a pathogen (Protective for breast fed infants).
_____is usually directed against protein epitopes.
IgA1
_____is usually directed against polysaccharide epitopes.
IgA2
The most abundant of all the antibodies.
IgA
What is the most predominant isotype found in secretions and mucosal surfaces?
IgA (specifically Dimeric SIgA)
Where is most monomeric IgA found?
The serum
IgA is second to ____ in regards to being found in serum.
IgG
SIgA is secreted by salivary glands into the…..
Oral cavity