Introduction to Immunology Flashcards
T/F. The physiological function of the immune system is defense against infectious microbes.
True. However, even non-infectious foreign substances can elicit immune responses
Who is created with creating the first vaccine?
Edward Jenner.
Jenner theorized that the pus in the blisters which ____ (servants/milkmaids) received from _____(cowpox/smallpox) protected them from ____(cowpox/smallpox).
milkmaids; cowpox; smallpox
How is cowpox related to smallpox?
It is a disease similar to smallpox but much less virulent
Jenner’s vaccine is an example of ______, which is a reaction between an ____ and an ____ that was generated against a different but similar antigen.
crossreactivity; antigen; antibody
To this day, what is the only human infectious disease to have been completely eradicated from nature?
smallpox
What are the two components of the immune response to infection?
innate and adaptive immunity
What type of immunity is antigen specific? non-antigen specific?
adaptive immunity
innate immunity
The immune response develops with an “____” phase early after infection and with an “___” later phase.
innate; adaptive
Which type of immunity is ancient and involves barrier defenses?
innate immune response
Give some examples of physical barriers to infection.
Skin, Mucosal surfaces, Tears and saliva
What are examples of chemical barriers to infection?
fatty acids (inhibit growth) lysozymes and phospholipase (in tears/saliva - breakdown cell membranes) Low pH (in sweat/gastric - prevent growth) defensins (in lung/GI - antimicrobial activity) surfactants (in lung - enhance antigen clearance)
T/F. The normal flora of the skin and in the gastrointestinal tract can prevent the colonization of pathogenic bacteria by secreting toxic substances or by competing with pathogenic bacteria for nutrients or attachment to cell surfaces.
True
The innate immune response involves cells that ___ (are/are not) antigen specific.
are NOT
Where are all leukocytes derived from?
hematopoietic stem cells in bone marrow
Myeloid cells are _____ derived from a myeloid progenitor cell.
leukocytes
What types of cells are myleoid cells?
Granulocytes (basophils, eosinophils, neutrophils)
Monocytes/macrophages
Dendritic cells
What cells are granulocytes?
BEN: basophils, eosinophils and neutrophils
_____ (macrophages/monocytes) in circulation differentiate into ____( macrophages/monocytes) in tissue.
Monocytes; macrophages
Lymphoid cells are ____ derived from lymphoid progenitor cells.
leukocytes
Natural killer cells are derived from ____ but are part of the ___, not ____, immune cells.
lymphocytes; innate; adaptive
T cells and B cells are ____ (innate/adaptive) immune cells.
adaptive
What are the three types of lymphoid cells?
NK cells, T cells and B cells
Which cell type is a large phagocytic cell with a multilobed nucleus and contains an arsenal of lysozymes and antibiotic proteins? It is found in 50-75% of blood leukocytes in humans and is often the first cells to respond to “trouble”. They rapidly respond to chemotactic agents and produce chemotactic agents for other leukocytes in addition to phagocytose invading microorganisms or particles.
Neutrophils
Which is found in tissues not blood, basophils or mast cells?
mast cells
Which cells comprise 0.2 % of blood leukocytes (very low numbers)?
basophils
___ and ___ cells principal trigger is ___ mediated surface receptor cross-linking. They release multiple inflammatory mediators, but ___is the primary mediator. They are protective during inflammation but ___ role in allergy.
Basophils; mast; IgE; histamine; pathological
Which cell type comprises 2-5 % of blood leukocytes in non-allergic individuals and have characteristic bi-lobed nucleus?
Eosinophils
Eosinophils principle function of ___ mediated ___and eradication of large extra-cellular ____ (helminthic parasites, worms) and their proportions rise during ___ reactions.
IgE; degranulation; parasites; allergic
What cells comprise 5-15% of blood lymphocytes and kill virally infected and tumor cells?
NK cells
NK cells ___ (do/do not) need MHC for Ag recognition.
do NOT. (in fact they kill cells lacking MHC)
What cells are extremely important for antigen presentation and clearance of dead cells & debris?
Monocytes/Macrophages
Which cells are the first to respond to “trouble”? second?
neutrophils; monocytes/macrophages
What cells are very large (10 - 20 µm in diameter) phagocytic cells with a large nucleus that make up 5-10% of blood leukocytes? They are often the second cell to respond to “trouble” and produce chemotactic agents for other leukocytes, contain arsenal of lysozymes and antibiotic proteins, and phagocytose microorganisms, particles, & tumor cells.
Monocytes (blood)/Macrophages (tissue)
Dendritic cells are phagocytic cells that make up a ____ population in the blood, but:
found in skin, mucosa, lymph nodes, spleen, thymus. They typically express ____ molecules, internalize and process ____ and present Ag ____ within ___ on surface. This is important for presenting Ag to ____ and important for activating T cells.
minor; MHC II; antigen; peptides; MHC II; T cells
What cells type is the link between innate and adaptive immunity?
dendritic cells
Of all the cells, which ones are phagoctytic?
neutrophils, monocytes/macrophages, dendritic cells
Why are lymphocytes extremely important for adaptive immunity?
immunologic specificity
immune regulation
immune memory (basis of vaccines)
T/F. The mechanisms of adaptive immunity provide the initial defense against infections. Innate immune responses develop later and consist of activation of lymphocytes. The kinetics of the innate and adaptive immune responses are approximations and may vary in different infections.
False. The mechanisms of INNATE immunity provide the initial defense against infections. ADAPTIVE immune responses develop later and consist of activation of lymphocytes. The kinetics of the innate and adaptive immune responses are approximations and may vary in different infections.
Adaptive immunity is comprised of both a ___ arm and a ___-___ arm.
humoral; cell-mediated
Which arm is effective against extracellular microbes?
humoral
The ___-___ arm is primarily effective against intracellular pathogens.
cell-mediated
In humoral immunity, ___ lymphocytes secrete antibodies that prevent infections by and eliminate ____ microbes. In cell-mediated immunity, helper ___ lymphocytes activate macrophages to kill phagocytosed microbes or cytotoxic T lymphocytes (CTLs) directly destroy infected cells.
B; extracellular; T
___ lymphocytes recognize soluble antigens and develop into antibody-secreting cells. ___ T lymphocytes recognize antigens on the surfaces of APCs and secrete cytokines, which stimulate different mechanisms of immunity and inflammation. ___ T lymphocytes recognize antigens on infected cells and kill these cells. ___T cells suppress and prevent immune response, e.g. to self antigens.
B; T; Cytotoxic; Regulatory
How do we tell immune cells apart?
Cluster of Differentiation (CD) markers
T/F. CD3+ cells are B cells
False. CD3+ cells are T cells
T/ F. CD3+CD4+ cells are CD4+ T cells (or Helper T cells)
True
T/F. CD3+CD8+ cells are CD8+ T cells (or Cytotoxic T Cells)
True.
An ___ is any substance that can be specifically bound by a cell of the adaptive immune system.
antigen
T/F. An tolerogen is an antigen that ellicts an immune response.
False. A tolerogen induces immunological tolerance or immune non-responsiveness.
An ___ is an antigen that ellicits an immune response.
immunogen
What is an antigen that causes an immediate hypersensitivity (allergic) reaction?
allergen
___ antigen are generated within the cells of the body as a result of normal metabolism or viral infection. These are antigens presented by APCs to ___ T cells.
Endogenous; CD8+
___ antigen directly enter the body from the environment. These are antigens presented by APCs to ___ Tcells.
Exogenous; CD4+
Where does innate immunity develop? adaptive immunity?
site if infection
regional lymph nodes
Where do B cell mature? T cells?
bone marrow
thymus
T/F. Lymphocytes enter secondary (peripheral) lymphoid organs as “naive” lymphocytes. Antigens are captured from their site of entry by dendritic cells and concentrated in lymph nodes, where they activate naive lymphocytes that migrate to the nodes through blood vessels.
True
T/F. Effector and memory T cells develop in the nodes and enter the circulation, from which they may migrate to peripheral tissues. Antibodies are produced in lymphoid organs and enter the circulation, from which they may locate antigens at any site. Memory cells also enter the circulation and may reside in lymphoid organs and other tissues.
True
How do APCs enter the LN - lymph circulation or blood vessel?
lymph circulation
How do Naive T and B cells enter lymph nodes - lymph circulation or blood vessel?
blood vessel
Which zone within the lymph node would you find T cells? B cells?
T Cells - Parafollicular cortex
B Cells - Lymphoid follicle
What does activation of naive lymphocytes lead to?
clonal expansion and differentiation into effector and memory lymphocytes
____ T cells and ____ enter into tissue and eliminate antigen.
Effector; antibodies
Which lymphocytes take up residence in tissue and secondary lymphoid organs in preparation for the next infection?
Memory lymphocytes
T/F. Adaptive immunity takes longer to develop.
True.
What are the five phases of adaptive immune response?
- antigen recognition
- lymphocyte activation
- antigen elimination
- contraction (homeostasis)
- memory
Which phase of adaptive immune response does differentiation and clonal expansion occur?
lymphocyte activation
Which phase of adaptive immune response does humoral immunity and cell-mediated immunity occur?
antigen elimination
Which phase of adaptive immune response does apoptosis occur?
contraction (homeostasis)
T/F. If no antigen is being presented, T cells leave and re-enter the circulation.
True.
T/F. If antigen is present, immune cell is activated prior to exiting and going to site of peripheral infection/inflammation.
True
How do leukocytes avoid the shear force exerted by blood flow?
They use post-capillary venules that have less shear force and thin vessel walls.
How do leukocytes overcome electrostatic interactions?
There is a net (-) charge on endothelia and inflammatory cells but electrostatic grasping can occur after injury/infection due to changes in charge distribution.
What is the name of these postcapillary venules located in the T cell zones?
high endothelial venules (HEVs)
Naive T cell migration out of the blood through the ___ into the lymph parenchyma is a multistep process.
HEVs
This process consist of ___-mediated rolling of the cells, chemokine-induced ___ activation, integrin-mediated firm ___, and ___ through the vessel wall.
selectin; integrin; adhesion; transmigration
L-selectin ligand on the ___ binds to selectin on the ___ cell.
leukocyte; endothelial
Cytokines increase E- and P- selectin on ___ cells and selectin ligand on __ cells.
endothelial; T
What interaction allow leukocytes to slow down and roll?
intergin binding to intergin ligands
What causes leukocytes to stop rolling and migrate to the site of infection?
cytokines
How does the innate immune response respond to invading pathogens?
N-formyl-methionyl receptor
Mannose receptor
Scavenger receptor
TLRs
Which TLR recognizes LPS (gram - bac)? Peptidoglycan (gram + bac)?
TLR4
TLR2
What type of receptors are highly conserved across species and are known as Pattern recognition receptors?
Toll-like receptors
Toll-like receptors recognize molecules that are broadly shared by pathogens but distinguishable from host molecules, collectively referred to as ___-___ ___ ___.
pathogen-associated molecular patterns (PAMPs).
What is the immune consequence of TLR recognition of a PAMP?
The consequence affects both the innate and adaptive immune response. It causes expression of cytokines, chemokines, endothelial adhesion molecules, costimulatory molecules and antiviral cytokines.
what is the signaling cascade for the Toll-like receptor?
adaptor proteins activate protein kinases that activate transcription factors. NF-kB is involved in this process.
CD___+ T cells recognize Antigen+MHCII and CD___+ T cells recognize Antigen+MHCI
4; 8
What accessory receptor causes a signaling transduction cascade when the TCR recognizes its antigen+MHC?
CD3
The T cell receptor only recognize processed ___ fragments presented by ___ on the surface of antigen presenting cells.
antigen; MHC
The B cell receptor recognizes soluble intact ___ and small ___.
macromolecules; chemicals
What are the two types of antigen specific receptors?
B and T cell receptors
