Immunology Exam 1

What cells are apart of the myeloid line?

1. Neutrophils

2. Basophils

3. Mast cells

4. Eosinophils

5. Macrophages

6. Dendritic cells

What cells are apart of the lymphoid line?

1. B cells

2. T cells

3. NK cells

4. Dendritic cells

What is the only cell that can come from both lines?

Dendritic cell

What is the highest concentration of white blood cells in blood?

1. Neutrophils

2. Lymphocytes

3. Monocytes

4. Eosinophils

5. Basophils

   “Never Let Monkeys Eat Bananas”

What are the myeloid antigen presenting cells?

1. Macrophages

2. Dendritic cells

What are the three lines of defense? (TQ)

1. Physical barriers (Innate)

2. Cells, complement, and inflammation (Innate)

3. B cells and T cells (Adaptive)

What is the first line of defense?

Physical barriers- things that you are born with/epithelial surfaces

What are examples of 1st line of defense?

Skin, mucous membranes, chemical barriers, gut microbiome

What is the only 1st line of defense you are not born with?

gut microbiome

What proteins are 1st line of defense?

1. Lysozyme

2. Lactoferrin

3. Secretory leukocyte protease inhibitor

4. S100 proteins

5. Defensins

Urine, saliva, and tears are apart of what line of defense?

1st line of defense

What is 2nd line of defense?

made in response to injury/infections, born with

What are examples of 2nd line of defense?

innate white blood cells, complement, and infalmmation

What is the teams of 2nd line of defense?

Phagocytic Team

1. Macrophages- kill, antigen presentation

2. Neutrophils- professional killers, pus

3. Dendritic cells- liaison between innate and adaptive immune systems

T/F PAMPs and PRR are associated with 2nd line of defense

True

What is a PAMP?

pathogen associated molecular pattern

on the pathogen

What is a PRR?

pattern recognition receptor

toll like receptor that sees PAMPs

What other two things are associated with the innate team?

1. Natural killer cells- kill without previous exposure

2. Complement system- 40+ proteins produced by the liver→flood blood→forms membrane attack complex (MAC)→punches holes in bacterial cells to kill

What are two examples of highly inflammatory cytokines? (TQ)

1. TNFa

2. Interleukin1

What is role of cytokines?

recruit fluid, cells, and molecules to the site of infection →swelling

T/F inflammation is an innate immune cell response

True

What is the 3rd line of defense?

adaptive, specific

acquire it after exposure to pathogen

What cells are associated with 3rd line of defense?

1. B cells: (humoral immunity)- make antibodies in blood

2. T cells: (cell mediated immunity)

What is required by T cells for activation?

Antigen presenting cells

1. Dendritic cells

2. macrophages

3. B cells

T/F Neutrophils are antigen presenting cells

False- phagocytic

What is MHC?

major histocompatibility complex aka (HLA)

What is MHC-1?

surface of most cells, displays what is going on in cells

What is MHC-II?

surface of APC’s only, displays what is going on in the cells

What is a cytokine?

hormone-like messengers produced by immune cells, communicate with other cells to affect immune response (IL-1, TNF)

What is apart of the 2nd line of defense?

1. Complement proteins

2. Phagocytes

3. Natural killer cells

4. Innate lymphoid cells

What are the complement system functions?

1. Opsonization

2. Chemotaxis/chemoattractant

3. Directly kills pathogens lysis (MAC)

What is opsonization?

tags, coats pathogen with C3b to enable phagocytes to engulf/destroy

What is chemotaxis?

acts as chemical signals to attract phagocytes: enhances bactericidal actions of phagocytes

Complement is made of a series of ___

zymogens- inactive enzymes

The complement system requires activation by what?

1. Classical pathway (antibody dependent)

2. Alternative pathway

3. Lectin pathway

How is the classical pathway initiated?

initiated by antibody forming an antibody-antigen complex

What does the classical pathway require for binding to antigen?

IgM or IgG

What C1 binds to the antibody-antigen complex?

C1q- causes confirmational change to C1r

Once C1r undergoes conformational change, what is activated?

C1s

Once C1s are active, they cleave ___ and ___

C4 and C2

C1s cleave ____

C4→C4a + C4b

C2→C2a to C2b

C4b and Ca2 combine to give us ____

C4b2a= C3 convertase

What does the C3 convertase cleave?

C3

C3 convertase cleaves C3 into?

C3a + C3b

When C4b2a combines with C3b it becomes ___

C4b2a3b= C5 convertase

C5 convertase cleaves into ___

C5a+ C5b

C5b starts the process of the Big MAC attack which includes what?

C5b+C6+C7+C8+ lot of C9= MAC= lysis death

T/F Big MAC attack is used by all three pathways

true

What is MBL and what does it mean?

Mannose- binding lectin protein→binds to carbohydrate

Which of the following pathways uses PAMP and PRR to start? (TQ)

Lectin Pathway

Once MBL binds to carbohydrate, what happens next?

MBL→MASP1→MASP2

MASP2 cleaves ___

C4 and C2 (same as classical)

What are the chemoattractants?

C4a, C3a, C5a = inflammation

What is the “oldest” pathway?

Alternative pathway

What starts the alternative pathway?

C3→ C3a +C3b

C3b binds to an amino group or hydroxyl group on cell surface

What happens after C3b binds to an amino group or hydroxyl group?

Factor B binds to C3b creating C3bB

What happens after C3b +Factor B?

Factor D cuts off a part of B creating C3bBb

What is the alternative C3 convertase?

C3bBb

What does C3bBb do?

creates a positive feedback loop covering the surface of the pathogen with C3bBb

What is an alternate C5 convertase? (TQ)

C3bBbC3b

What prevents MAC attack?

protectin→blocks C9 recruitment which prevents cell death

What are the professional phagocytes?

1. Macrophages

2. Neutrophils

3. Dendritic cells

What is the main function of professional phagocytes?

engulf and digest invading microorganisms→induction of inflammatory response

What are macrophages?

roam around in the tissue

start as monocytes in blood and become marcrophages once in the tissues

Garbage collectors at rest

What are neutrophils?

roam around in blood

short lives

always damage tissues , very phagocytic, see pus

MHC-1 is on the surface of ___ and are scanned by ___ cells which can kill infected cells

body cells

CTL

MHC-II is on the surface of ___ and displays things they have ___

APC’s

eaten

How does a at rest macrophage become primed (activated)?

receive signal from other cells that barrier is breached and pathogen is present

Cytokine signals can prime a macrophage

When do macrophages go from active to hyperactive?

after receiving a direct signal from pathogens

stop proliferating and grow larger

Neutrophils use what strategy for leaving the blood?

Roll, stop, exit strategy= extravasation

What is extravasation?

the process of WBCs exiting the blood and entering into tissues at the sight of injury or infection

What are the neutrophil adhesion molecules?

1. SEL- expressed by enodthelial cells in response to alarm (IL-1, TNF)

2. SLIG- (selectin ligand) expressed on surface of neutrophils

3. ICAM (intracellular adhesion molecule)- expressed on lumen surface of capillary endothelial

4. INT (integrin)- premade and rapidly transported to neutrophil after signaled by (C5a and LPS)

What is INT bind to?

ICAM and stops neutrophils

What adhesion molecules are always present?

ICAM and SLIG

What is diapedesis?

neutrophils exit the blood and go into tissue

Neutrophil must have ___ before rolling

SEL

Neutrophil must have ___ before stopping

INT

Neutrophils must have ______ before diapedesis

chemoattractant C5a and fmet

Innate immune system is composed of ___

1. Complement proteins

2. professional phagocytes

3. NKC

4. lymphoid cells

What is the role of the innate immune system?

1. give off cytokines

2. force cells to apoptosis

With NKC, if target cell has MHC-1 receptors=

dont kill signal

With NKC, if unusual PAMPS are on cell surface=

kill signal when PRR see PAMP, also kills cells not expressing MHC-1

What signals activate NK cells?

1. lack of MHCs

2. unusual proteins displayed on MHC-1→ DAMPs, IFN-a, IFN-b

What are the two ways that NK cells kill?

1. Perforin→protein pokes hole in membrane→injects enzymes→ trigger apoptosis

2. Fas ligand→on NK binds to FAS protein→interaction triggers apoptosis

T/F Apoptosis is cleaner and neater than necrosis

true

What is innate and kills by cytokine?

ILC→ innate version of helper T cells

What is the innate version of CTL/killer T cells?

NK cells

A major way to block virus is to use___

IFN1

Using INF1 can do what?

1. inhibit viral protein synthesis

2. degrade viral RNA

3. inhibit gene expression and assembly

Humoral immunity is mediated by ____ which are produced by ____

antibodies

B lymphocytes

Cell mediated immunity is mediated by ___

T lymphocytes

principle defense against intracellular pathogens

What is the main function of B cells?

make antibodies (immunoglobulins)

T/F Each B cell has B cell receptors that give the distinct types of B-cells

true

What is the Fab region of an antibody?

binds to antigens “hands”

What is the Fc region of an antibody? (TQ)

binds to B cells “tail”

determines the class of Ab

T/F heavy chains are held together by 1 disulfide bridge?

False- 2

T/F light chains are held together by 1 disulfide bridge

true

What is an antigen?

any substance that elicits a specific response by B or T lymphocytes

What do B cells read?

foreign proteins, polysaccharide, or lipids

What do T cells read?

foreign protein