Microbio Week 4 (Exam 2) Flashcards by A G

Q

Any substance that induces a specific adaptive immune response (T and B cells)

A

Antigen

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Examples of antigens

A

Proteins
Nucleic acids
Lipids
Polysaccharides
Metals

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Each microbe possesses many different ___________

A

antigens

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Primary immune response to antigen

A

First antigen encounter

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Secondary immune response to antigen

A

Second encounter with same antigen

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Characteristics of innate immunity

A

Immediate
Non-specific
No memory

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Which type of immunity is always present to block microbe entry?

A

Innate immunity

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Characteristics of adaptive immunity

A

Delayed
Specific
Has memory

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does adaptive immunity require?

A

Expansion/differentiation of lymphocytes

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What are the 2 types of adaptive immunity?

A

Humoral
Cell-mediated

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Which type of adaptive immunity?

Mediated by antibodies; extraceullar microbe

A

Humoral immunity

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Which type of adaptive immunity?

Involves T lymphocytes; intracellular microbe

A

Cell-mediated immunity

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Which type of adaptive immunity?

Blocks infections and eliminate extracellular microbes

A

Humoral immunity

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Which type of adaptive immunity?

Elimination of phagocytosed microbes

A

Cell-mediated immunity

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Which type of adaptive immunity?

Kills infected cells and eliminates reservoirs of infection

A

Cell-mediated immunity

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Adaptive immunity recognizes microbial antigens on _________ or ________ _______ surfaces

A

microbes; host cell

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Describe the steps of clonal selection

A

Lymphocyte clones w/ diverse receptors arise in lymph organs
Clones of mature lymphocytes specific for many antigens enter lymph tissue
Antigen-specific clones are activated by antigens
Antigen-specific immune responses occur

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

How long is the primary memory response?

A

1-3 weeks

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

How long is the secondary memory response?

A

2-7 days

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Which memory response mounts larger and more effective responses to repeated antigen exposures?

A

Secondary memory response

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Name some cells involved in innate immunity (immediate response) (6)

A

Macrophages (WBCs)
NK cells
Dendritic cells
Neutrophils
Eosinophils
Basophils

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Name some cells involved in adaptive immunity (delayed response)

A

B cells
T cells (CD4 & CD8)

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Name some cells involved in both innate and adaptive immunity

A

T cells
NK T cells

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Name the type of cell:

Circulates and initiates response upon recognition of antigen

A

Lymphocyte

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Name examples of lymphocytes

T lymphocytes B lymphocytes

Name the type of cell: Detects presence of microbes

Antigen-presenting cell

Name examples of antigen-presenting cells

Dendritic cells Macrophages B cells

Name the type of cell: Destroys microbes

Effector cells

Name examples of effector cells

T lymphocytes Macrophages Granulocytes

Where do B cells mature?

Bone marrow

Where do T cells mature?

Thymus

Which type of lymphocyte? Neutralization of microbe, phagocytosis, complement activation

B lymphocyte

Which type of lymphocyte? Activation of macrophages, inflammation, activation (proliferation/differentiation) of T and B lymphocytes

Helper T lymphocyte

Which type of lymphocyte? Killing of infected cells

Cytotoxic T lymphocyte

Which type of lymphocyte? Suppression of immune response

Regulatory T lymphocyte

What type of T/B cell? Survive for weeks-months and die if no antigen

Naive T/B cell

What type of T/B cell? Short lived, die when antigen is eliminated

Effector T/B cell

What type of T/B cell? Survive for long period of time

Memory T/B cell

__________ T cells are more numerous in young people

Naive

__________ T cells are more numerous in old people

Memory

____________ occurs in primary lymph organs

Maturation

____________ occurs in secondary lymph organs

Activation

Name the primary lymph organs

Thymus Bone marrow

Name the secondary lymph organs

Spleen Lymph nodes

What does organization of secondary lymph organs enable? (3)

1. APCs to concentrate antigens 2. Lymphocytes to identify/respond to antigens 3. Cells to interact

Where does lymph drain to?

Lymph nodes

Draining of lymph to lymph nodes allows for what 2 things?

1. Concentrate antigens 2. Sampling of antigens by APCs

Lymph nodes and the spleen have distinct ___ and ___ cell zones

B and T

________ _______ pick up antigens in tissues and migrate to lymph nodes

Dendritic cells

Blood entering the spleen allows for what?

Sampling of antigens by APCs

Activated ___ _________ migrate in tissues to eliminate microbes

T cells

The mucosal immune system is a collection of lymph tissue that is similar in organization as what?

Lymph nodes (tonsils, Peyer's patch)

How is movement of T and B cells coordinated?

Chemokines and receptors

____ _________ are attracted in __________ in lymph organs

B cells; follicles

____ _________ are attracted ___________, but adjacent to follicles in lymph organs

T cells; outside

How does the immune response to microbes occur? (3 steps)

1. Antigen recognition 2. Cell activation 3. Antigen elimination

Name the 5 phases of the adaptive immune response

1. Antigen recognition 2. Clonal expansion 3. Differentiation in effector cells 4. Contraction via apoptosis 5. Memory cells

__________ __________ __________ capture antigens and concentrate it in lymph organs where the organization allow them to present it to ____ __________

Antigen presenting cells; T cells

__________ T lymphocytes circulate through lymph organs, whereas ____________ T cells migrate to tissue where inflammation/infection is present

Naive; effector

Lymphocytes divide in response to what?

Antigens

What do lymphocytes become after they divide in response to antigens?

Effector and memory cells

Innate immunity is essential for...?

Effective host defense at early stage of infection

Adaptive immunity is essential for...?

Microbe clearance

Innate immunity varies according to _________ type

microorganism

What are the 2 categories of microorganisms involved in innate immunity?

Extracellular and intracellular

Extracellular or intracellular microorganism? Accessible to soluble molecules and phagocyte

Extracellular

Extracellular or intracellular microorganism? Require killing or activation of infected cells

Intracellular

Extracellular or intracellular microorganism? Complement, macrophages, neutrophils

Extracellular

Extracellular or intracellular microorganism? Antimicrobial peptides

Extracellular

Extracellular or intracellular microorganism? NK cells

Intracellular

Extracellular or intracellular microorganism? Activated macrophages

Intracellular

Innate or adaptive immunity? Recognizes structures shared by various classes of microbes, but not present on normal host cells

Innate

Innate or adaptive immunity? Pattern recognition receptors (PRRs) encoded in germline possess limited diversity

Innate

How do cells of the innate immune response identify microorganisms?

Pattern recognition receptors (PRRs) recognize pathogen associated molecular patterns (PAMPs)

Molecules expressed and/or produced solely by microbes and recognized by PRR expressed by immune cells

Pathogen associated molecular patterns (PAMPs)

Pattern recognition receptor (PRR) expression and ligands are __________

redundant

Pattern recognition receptors (PRRs) recognize similar types of ___________

ligands

Where are pattern recognition receptors (PRRs) found in cells?

Localized at plasma + endosomal membrane, and in the cytosol

What are pathogen associated molecular patterns (PAMPs) recognized by?

Toll-like receptors (TLRs)

Where are toll-like receptors (TLRs) expressed on?

Cells of the innate immune system

During toll-like receptor (TLR) signal transduction, recruitment of adaptor proteins, ________ and __________, leads to activation of ________________ factors and ___________ production

MyD88; TRIF; transcription; cytokine

____________ recruits TRIF and triggers IFNa/B production

TLR3

During toll-like receptor (TLR) signal transduction, activation of transcription factors leads to increased expression of cytokines, adhesion molecules, and costimulators. This causes what 2 things to occur?

1. Acute inflammation 2. Stimulation of adaptive immunity

During toll-like receptor (TLR) signal transduction, activation of transcription factors also leads to production of type 1 interferon. This causes what to occur?

Antiviral state

How many types of inflammasomes are there?

14

Activate inflammatory processes and provides host defense; involved in chronic disease development

Inflammasomes

How is the NLRP3 inflammasome assembly initiated?

By sensing several molecules (ex: microbial products, inorganic particles, endogenous substances, etc)

What does inflammasome assembly lead to? (4)

Caspase-1 activation Cleavage of pro-IL1B Secretion of IL1B Accumulation of neutrophils + monocytes at site

What are the components of the innate immune system?

Epithelial barriers Phagocytes NK cells Granulocytes

Name the 3 types of barriers of the epithelia

1. Physical barrier 2. Chemical barrier 3. Cellular barrier

Which barrier: physical, chemical, or cellular? Saliva (oral cavity)

Physical barrier

Which barrier: physical, chemical, or cellular? Kill microbes by disrupting outer membranes of bacteria and some virus

Chemical barrier

What cell? Most abundant (1x10^11/day) Short lived (6 hrs in blood) No lysosome

Neutrophils

What do neutrophils mediate?

Earliest phase of inflammatory responses

What cell? 10x less abundant than neutrophils Long lived Monocytes differentiate into macrophages in tissues

Mononuclear phagocytes

What do macrophages mediate?

Later stages of innate immune response, 1-2 days after infection

What cells divide and persist at inflammation site?

Macrophages

What is the function of classical/M1 macrophages? (2)

1. Trigger inflammation 2. Kill micobes

Dendritic cells have __________ and __________ capabilities

dendrites; phagocytic

What cells link innate and adaptive immune responses?

Classical dendritic cells

What cells? Capture and display microbial antigens to naive T lymphocytes

Classical dendritic cells

What cells? Tune T cell response by secreting cytokines

Classical dendritic cells

What do plasmacytoid dendritic cells produce?

Type 1 interferons (IFNa/B) that have antiviral activities

What cell? Bind dsRNA via TLR3

Plasmacytoid dendritic cells

What cell? Do not express somatically rearranged clonally distributed antigen receptors; are NOT phagocytes

NK cells

Inhibitory receptor engagement to MHC class I inhibits _________ cell activation

NK

Signals from ____________ receptors block signals from ____________ receptors

inhibitory; activating

Lack of inhibitory receptor engagement triggers _____________

activation

What happens to NK cell if the inhibitory receptor is engaged?

NK cell = not activated No cell killing!!

What happens to NK cell if inhibitory receptor is NOT engaged?

NK cell = activated Killing of infected cell occurs

What cell? Kill virus-infected cells via perforin/granzyme

NK cells

What cells? Upon activation, release proteolytic enzymes and substances that contribute to inflammation

Mast cells, basophils, and eosinophils

Name some examples of proteolytic enzymes and substances released by mast cells, basophils, and eosinophils that contribute to inflammation (5)

Histamine Prostaglandins Heparin Leukotrienes TNFa

What cells? Important in helping to protect against helminth and bacterial infection

Mast cells, basophils, and eosinophils

Lymphocyte activation requires how many signals?

2

What are the 2 signals involved in lymphocyte activation?

Signal 1 = antigen binding to antigen receptor Signal 2 = molecules provided by innate cells

4 principal effects of inflammation

1. Increase in temp (calor) 2. Redness (rubor) 3. Swelling (tumor) 4. Pain (dolor)

What are 3 mediators secreted in response to bacterial infection?

Histamine Prostaglandins TNFa

During an acute inflammatory response, the increased _____________ permeability of mediators leads to influx of _________ _________ and ________ cells. This contributes to swelling, redness, heat, and pain

capillary; plasma proteins; phagocytic

How do cells at the site of infection alert other innate cells of the immune response?

Cytokines attract and activate cells, or induce cellular processes

__________ induce innate cells to produce _________

Microbes; cytokines

Cytokines are produced by __________ cells upon interaction with infectious agents, and activate/mobilize other cells

innate

What is an effect of cytokines on vascular endothelium?

Endothelial wall gains new adhesion proteins specific for interactions with leukocytes

What 3 parts of the body do inflammatory cytokines have an effect on systemically?

1. Liver 2. Hypothalamus 3. Fat, muscle

Liver, hypothalamus, or fat + muscle? Systemic effect of inflammatory cytokines includes: activation of complement; opsonization

Liver

Liver, hypothalamus, or fat + muscle? Systemic effect of inflammatory cytokines includes: increased body temp; decreased viral and bacterial replication

Hypothalamus

Liver, hypothalamus, or fat + muscle? Systemic effect of inflammatory cytokines includes: protein and energy mobilization to generate increased body temp; decreased viral and bacterial replication

Fat + muscle

What cytokines are involved in an abscess?

TNFa and IL1

Name the 4 steps in the recruitment of leukocytes: transmigration

1. Rolling 2. Integrin activation by chemokines 3. Stable adhesion 4. Migration through endothelium

What are the 3 liver plasma proteins that serve as acute phase reactants?

SAP CRP MBL

What do acute phase reactants function as?

Opsonin, targeting microbes for phagocytosis

Molecules coating microbe surface

Opsonin

Process of marking microbe for ingestion

Opsonization

What do opsonins simultaneously bind to?

Microbe + phagocyte receptor

What do acute phase reactants activate?

Complement

In the complement system, what do all pathways lead to?

Cleavage of C3 into C3b and C3a

What enzyme is responsible for cleavage of C3 into C3b and C3a?

C3 convertase

What is C3b?

Opsonin

What is C3a?

Anaphylatoxin

C3a and C5a induce local inflammatory responses. Name them

Increased vascular permeability Increased microbicidal activity

Which process triggered by opsonization leads to microbe ingestion?

Phagocytosis

What can we compare phagocytes to?

Pac-man

What cells kill microbes?

Neutrophils Macrophages

What cells process antigens?

Dendritic cells

Process of ingestion of opsonin-coated or receptor-bound microbes

Phagocytosis

How are microbes killed once phagocytosed?

Production of toxic products

The generation of what is toxic for ingested microbes?

O2- Reactive oxygen species (H2O2, OCl-, -OH) NO Reactive peroxynitrite radicals

What is pus?

Dying neutrophils

Antigens are transported from ___________ to lymph organs where recognition by ____ cells occurs

tissue/mucosa; T

The majority of dendritic cells in tissues and lymph organs are what type?

Classical dendritic cells

What cells capture and process protein antigens?

Immature dendritic cells

Dendritic cells upregulate __________ receptors (CCR7) and ____________ molecules

chemokine; costimulatory

What cells present protein antigens to T cells?

Mature dendritic cells

What determines the specific recognition of antigens by T cells?

MHC molecules

Antigens are displayed by ____ __________ and are recognized by ___ _______

MHC molecules; T cells

T cell receptors on T cells recognize peptide antigens displayed by _____ ___________ on antigen presenting cells

MHC molecules

How many sets of highly polymorphic genes are there? Name them

2 Class I MHC genes Class II MHC genes

Genes of the MHC locus are highly _________

polymorphic

MHC class I and class II molecules are membrane proteins containing a peptide-binding cleft at the ________ ___________

amino terminal

MHC class I molecules have an ________ chain associated with _______________

alpha; B2-microglobulin

MHC class II molecules have _________ and _________ chains

alpha; beta

CD8 T cells only recognized peptides presented by ....

MHC class I molecules

______ binds CD8 on CD8 T cells

a3 (invariant portion of alpha chain)

CD4 T cells only recognized peptides presented by ....

MHC class II molecules

______ binds CD4 on CD4 T cells

B2 (invariant portion of beta chain)

What ensures that a population can deal with microbe diversity?

MHC polymorphism

What is expressed on APCs and induced by IFNgamma?

MHC class II molecules

What is expressed on ALL nucleated cells?

MHC class I molecules

MHC molecules only bind peptides derived from what?

Protein antigens

T/F: One APC can display multiple peptides

True

How are are proteins converted into peptides?

Antigen processing pathways

Peptide binding to MHC lasts up to ______ in order to maximize interaction with ___ _______

days; T cells

Extracellular proteins (tumor, bacteria) are processed in ______________. Peptides are displayed on MHC class _____ molecules to ______ cells

endosome/lysosome; II; CD4

Cytosolic proteins (virus, bacteria that escape phagosome) are processed by ___________ and _____________ ___________. Peptides are displayed on MHC class _____ molecules to ______ cells

proteasome; endoplasmic reticulum; I; CD8

What is the significance of MHC-associated antigen presentation?

Optimization of response to different microbes in different locations (extracellular = CD4; intracellular = CD8)

Which inflammatory cytokines affect the liver?

IL-1 IL-6 TNFa

Which inflammatory cytokines affect the hypothalamus and fat + muscle?

IL-1 TNFa