Cell Test 3

Front 1

What is diffuse lymphatic tissue?

Back 1

Scattered lymphocytes, plasma cells. Only efferent vessels. Beneath wet epithelia.

Front 2

What does a primary nodule lack?

Back 2

A germinal center (central pale zone).

Front 3

What makes up a germinal center?

Back 3

Lymphocytes and follicular dendritic cells

Front 4

Describe the blood supply of lymph nodes.

Back 4

At the hilum arteries enter, veins leave. Postcap venules in paracortex.

Front 5

Where are reticular cells found and what do they do?

Back 5

Part of the sinus wall and in stroma. Specialized fibroblast that produce collagen III. Also produce cytokines to attract lymphocytes and dendritic cells.

Front 6

Where are Dendritic cells and what do they do?

Back 6

From bone marrow, APC to T lymph

Front 7

Where is the thymus from embryologically?

Back 7

3rd and 4th pouch endoderm

Front 8

What happens in the thymus' cortex?

Back 8

Lymphocytes undergo selection, differentiation and maturation. Macrophages phagocytosing apoptotic lymphocytes.

Front 9

Where are Hassall's corpuscles found?

Back 9

The medulla of thymus

Front 10

What are the 3 types of Thymic epithelial cells?

Back 10

Cortical epithelial cells
Thymic epithelial cells type 3 & 4
Medullary epithelial cells

Front 11

What 2 structures would one find in thymic epithelial cells?

Back 11

Desmosomes and tonofibrils (keratin intermediate filaments)

Front 12

Name the 2 types of Cortical epithelial cells

Back 12

Subcapsular epithelial cells (tight junc)
Nurse cells/Inner cortical epithelial cells

Front 13

Which type of cell is involved in the blood-thymus barrier?

Back 13

Subcapsular epithelial cells

Front 14

What is the function of the thymic epi cells?

Back 14

B/T barrier
Form loose meshwork
Educate T lymph
Make cytokines and hormones
Form Hassall's corp

Front 15

What structures does the spleen lack?

Back 15

Lymph sinuses and afferent lymph vessels

Front 16

What covers the spleen?

Back 16

Peritoneum

Front 17

Name the encapsulated lymph organs

Back 17

Spleen, thymus, lymph nodes

Front 18

Where are central arteries found in the spleen?

Back 18

white pulp

Front 19

What are splenic cords (Billroth cords)?

Back 19

The tissue between sinusoids in the spleen red pulp that contain many MO and RBCs

Front 20

What are the branches off of the central arteries in the spleen called?

Back 20

Penicillar (straight arteries). Terminate into arterial cap (ensheathed by MO, reticular cells and lymphatic cells)

Front 21

Describe the open theory.

Back 21

In the spleen the arterial cap empty into the splenic cord spaces then passes between the endo cells of sinusoid to re-enter circ.

Front 22

What is the function of the spleen?

Back 22

Filter blood
Produce lymphocytes (B cells make antibodies)
Destroys old blood cells
Hematopoiesis in embryo
Blood storage

Front 23

What kind of lymph vessels do tonsils have

Back 23

Efferent

Front 24

Tonsils are collectively known as...?

Back 24

Waldyer's ring

Front 25

Which is the largest tonsil?

Back 25

Palatine

Front 26

Where are Peyer's patches found?

Back 26

Ileum

Front 27

What are M cells and what do they do?

Back 27

Cover Peyer's patchesand they endocytose macromolecules and transport them to underlying lymphocytes

Front 28

Name the cells involved in the Triumvirate

Back 28

Lymphocytes
Phagocytes
APC

Front 29

How do T cells recognize foreign fragments?

Back 29

Via epitopes presented to them by APCs via MHC

Front 30

Which cells are the only ones to possess Specificity, Discrimination, and Memory?

Back 30

B & T cells

Front 31

Where do B & T cells originate from?

Back 31

Hematopoietic Stem Cells (HSC)

Front 32

True or False: B cell education, differentiation, and maturation require the presence of exogenous antigen

Back 32

False

Front 33

What is important to note about the maturation, education, and differentiation of T cells?

Back 33

It occurs in the absence of exogenous antigen.

Front 34

What happens upon the "graduation" of B & T cells?

Back 34

They acquire cell membrane specific receptors for antigen and migrate and seed secondary lymph tissues

Front 35

What is Clonal expansion?

Back 35

When Ag interacts with the receptor, cell activates and divides --> clone of identical progeny whose receptors bind the same epitope. Also yields memory cells.

Front 36

What 3 things must an Ag be in order to be effective?

Back 36

1) Foreign (non self or altered self)
2) High Mol weight
3) complex & preferably protein

Front 37

What is a complete Ag?

Back 37

Protein
High mol weight
Chemical complexity
Degradability

Front 38

What kind of bond is there between an epitope and MHC?

Back 38

Noncovalent

Front 39

Any molecule that is not itself antigenic but when conjugated to a carrier protein becomes antigenic and induces Ab

Back 39

Hapten (incomplete Ag)

Front 40

Antigenic without the participation of T lymphocytes

Back 40

T-independent Ag

Front 41

What is characteristic about T-independent Ag?

Back 41

Having a structure that consists of repeating chemical units (ex: bacterial flagella) Antibody usually produced: IgM

Front 42

How is a superAg different than a regular Ag?

Back 42

Unlike regular Ag that bind to MHC cleft, the superAg bin the MHC-TcR independent of the cleft- they are not processed by APC

Front 43

What is the importance of superAg?

Back 43

Ability to non-specifically activate T cells resulting in abnormal amount of cytokines.

Front 44

Describe adoptive immunity

Back 44

Transfer of lymphoid cells (not Ab) from an actively immunized donor. T cells major player.

Front 45

What 4 things does Acquired immunity possess?

Back 45

1) Specificity
2) Adaptive
3) Discrimination
4) Memory (anamnestic response)

Front 46

What is the function of the MHC molecule?

Back 46

Function as antigen presenting structures for T cells

Front 47

Small fragments of cut up Ag

Back 47

Epitope

Front 48

MHC I: Ag?
To?
Need?
Important for...?

Back 48

Endogenous Ag
To Tc cells
Need CD8
Viruses (intracellular pathogens)

Front 49

MHC II: Ag?
To?
Need?
Important for..?

Back 49

Exogenous Ag
To Th cells
CD4
Pathogens that replicate outside cell

Front 50

MHC is found on what chromosome in humans?

MHC aka...?

Back 50

Chromosome 6

aka: HLA (Human Lymphocyte Ag)

Front 51

Which MHC Class is expressed on nearly all nucleated cells?

Back 51

MHC Class I

Front 52

What are the major regions in the human genome coding for Class I

Back 52

A, B, C

Front 53

Class I and II encode what type of proteins?

Back 53

Glycosylated

Front 54

MHC Class II is expressed on what type of cells?

Back 54

APCs

Front 55

What are the major regions in the human genome coding for Class II?

Back 55

DP, DQ, DR

Front 56

How are MHC genes inherited?

Back 56

Usually inherited as a group (closely linked).... One haplotype from mom, one from dad
*Polymorphic*

Front 57

How are MHC genes expressed?

Back 57

Codominantly

*progeny will generally not be able to accept grafts from parents since only have half from each*

Front 58

Describe the MHC Class I molecule

Back 58

Alpha chain: large, 3 external domains (1,2,3), transmembrane domain, cytoplasmic segment

Beta chain: invariant protein, gene not part of MHC

Front 59

Which portion of the MHC Class I molecule forms the Ag/peptide binding domain?

Back 59

alpha1 and alpha2

Front 60

Describe the "hotdog bun" of MHC Class I

Back 60

form a platform of 8 antiparallel B strands with 2 alpha helices forming borders... Groove holds 8-10 aa

Front 61

The MHC Class I Beta and Alpha chains look similar to what?

Back 61

Immunoglobin fold structure... They are considered part of the Ig Superfamily

Front 62

Which part of the MHC molecule is recognized by CD8?

Back 62

alpha3

Front 63

Describe the MHC Class II molecule

Back 63

Alpha chain and Beta chain associate via noncovalent bonds... 2 external domains alpha 1 and 2; beta 1 and 2....

Front 64

What region on the MHC Class II are considered Ig Superfamily members?

Back 64

alpha2 and beta2

Front 65

What region of the MHC Class II bind Ag?

Back 65

alpha1 and beta1

Front 66

What region of the MHC Class II is recognized by CD4?

Back 66

beta2

Front 67

How many different Class I molecules can each human express?

Back 67

Up to 6

Front 68

Describe the "promiscuity" of MHC molecules

Back 68

Can bind large # of peptides.... some peptides can bind more than one molecule

Front 69

In what form does the peptide bind in Class I and II?

Back 69

extended conformation inside the groove between the 2 alpha helices

Front 70

Of Class I and II molecules, which can hold more aa?

Back 70

Class II (13-25 aa)... Class II is more open, Class I is blocked at ends (8-10 aa)

Front 71

Which portion of the epitope/peptide makes more direct contact with the TCR and why?

Back 71

The middle portion of the peptide because the middle tends to hunch up and not make direct contact with the groove

Front 72

True or false:
Hunching is seen only in MHC Class I

Back 72

True

Front 73

True or false:
MHC Class II can bind and unlimited variety of peptides

Back 73

False... limited variety

Front 74

Describe the sequence in which MHC Class I presents Ag

Back 74

Ubiquitin attached--> degraded into peptides by proteasome--> IFN-gamma substitutes parts of proteasome to create immunoproteasome --> Peptide transported into RER by TAP--> peptide loaded into MHC assisted by calnexin, calreticulin, and tapasin --> trimer goes through golgi to surface

Front 75

Which cells can present endogenous Ag?

Back 75

Almost all cells since all nucleated cells have MHC Class I

Front 76

What does an immunoproteasome do?

Back 76

produce peptides with a hydrophobic or basic residue at the C terminus

Front 77

What happens when one lacks functional TAP?

Back 77

Bare lymphocyte syndrome.... immuno compromised

Front 78

What does the MHC Class I bind to until they can bind to the Beta segment?

Back 78

Calnexin

Front 79

Where does MHC Class I first bind on the peptide?

Back 79

C terminus

Front 80

What does ERAP do?

Back 80

(ER aminopeptidase) can cut off aa from the other end of the peptide to make it fit

Front 81

What are the most effective APCs?

Which need to be activated before expressing MHC Class II?

Back 81

Dentritic Cells

Macrophage

Front 82

Where do exogenous Ag come from?

Back 82

phagocytosed bacteria, Ag bound to Ab on surface of B cell

Front 83

What cells constitutively express MHC Class II?

Back 83

B cells

Front 84

Describe Ag presentation by MHC Class II

Back 84

Internalized--> degraded as it passes through acidic endosomal compartments--> Class II chains made and enter ER--> invariant chain associates with to fill groove (dummy)--> moves to golgi and join endosomes with peptide--> invariant chain degrades into CLIP--> CLIP exchanged for peptide with help of HLA-DM--> goes to surface

Front 85

What degrades the invariant chain?

Back 85

acidic pH and proteases

Front 86

Describe Cross Presentation

Advantage?

Back 86

APCs can present exogenous Ag to Tc in the context of MHC Class I... Ex: Dendritic cells

Advantage: can help get immune response to viruses faster

Front 87

Where is the diversity in MHC genes clustered?

Back 87

In parts of molecule that actually bind the peptides... specifically where the Ag actually binds

Front 88

Marek's Disease

Back 88

in chickens with MHC B19

Front 89

Akylosing spondylitits

Back 89

inflammatory disease leading to the stiffening of the vertebral joints in the spine

Front 90

What turns on and proliferates a B lymphocyte?

Back 90

Cytokines from T cells

Front 91

What synthesizes and secretes specific Ab?

Back 91

Plasma Cells

Front 92

What are the 3 major ways Ab protect the host?

Back 92

Neutralization
Opsonization (C3b)
Complement activation

Front 93

What percentage of serum is IgG

Back 93

~80%

*migrates in the gamma globulin fraction of serum protein sep*

Front 94

What are the 5 isotypes of Ig?

Back 94

IgG
IgA
IgM
IgD
IgE

Front 95

How are the 5 Ig Isotypes distinguished?

Back 95

Distinguished on the basis of aa structural differences in the C heavy chain

Front 96

How are Ab and BcR related?

Back 96

Antibodies are the SOLUBLE form of the BcR

Front 97

Which 2 isotypes are involved with the BcR?

Back 97

sIgM

sIgD

Front 98

True or false:
Each Ab differs in it's basic structure

Back 98

False:
All Ab have the same basic structure, they just differ in the regions that bind epitope

Front 99

The site associated with Ag recognition and binding

Back 99

Paratope

Front 100

What is the specificity of the Ab based on?

Back 100

The hypervariable regions within the paratope called CDR

Front 101

What are the 3 hypervariable regions within the VL and VH chains?

Back 101

HV1, HV2, HV3 aka (CDR1, CDR2, CDR3)

Front 102

Describe the composition of an Ab

Back 102

2 light and 2 heavy chains held together by inter-chain S-H bridges

Front 103

About how many aa make up the looped domains and how are they held?

Back 103

90-100 aa... Held in configuration by intra-chain disulfide bonds

Front 104

What is the N-term of the Ab characterized by?

Back 104

VH and VL

Front 105

POINT TO NOTE

Back 105

Arms of Ab identical --> V and C heavy and light chains composed of same aa sequences--> paratopes will bind identical epitopes--> Bivalent

Front 106

What is the hinge region composed of and what are their functions?

Back 106

Cysteine-- form the inter-chain disulphide bonds that hold heavy chains together

Polyproline-- allow flexibility of the 2 arms of Ab

Front 107

What is the Fc?

Back 107

The "tail" 2 heavy chain constant regions... Important for the biologic activity related to the Ab

Front 108

What is Fab?

Back 108

Describes each arm of the Ab made of L and H chains. Fab binds only one epitope...

*F(ab)2 describes both arms together --> bind 2 epitopes*

Front 109

Why is Fc important?

Back 109

1) Binding MO, PMNs, NK cells
2) Binding or fixing Complement
3) Transport Ab across membrane
4) Bind B cells during "education" and cR formation
5) Identify Ab isotype

Front 110

What is ISOtypic?

Back 110

Differences in the aa composition of H constant regions... 5 isotypes... gamma, alpha, mu, delta, epsilon

Front 111

Describe Allotypic

Back 111

Refers to allelic aa differences in the Ab C regions...serve as genetic markers (Gm, Am, Km)

Front 112

What is IDIOtypic?

Back 112

Within the L and H chains are hypervariable regions called CDRs (uniquely differ)...Remainder framework is the same for each Ab)

Front 113

An Ab directed against the Ag specific part of the sequence of an ab or TcR thus recognizing binding sites of other Abs or TcRs

Back 113

Anti-idiotypic Ab

Front 114

In principle, what should Anti-IDs do and when are they used?

Back 114

The should inhibit a specific immune response... important to Regulation of immune system... used in IVIG

Front 115

Where does Pepsin cleave an what are the resulting pieces?

Back 115

Cleaves below the disulphide bonds of H chain... leaves one F(ab)2 fragment and subfragments of Fc

Front 116

Where does Papain cleave and what are the resulting pieces?

Back 116

Cleave above the disulphide bonds of H chain... leaves 2 Fab fragments and 1 Fc

Front 117

How many isotypes do the L chains have?

How are they seen in the Ab?

Back 117

2: k and lambda

An Ab can have either kappas OR lambdas, never both

Front 118

What Chromosomes are Kappa and lamda from?

Back 118

Chromosomes 2 (k) & 22 (l)

*chromosome 14 H chain*

Front 119

What is Multiple myeloma?

Back 119

The most common gammopathies... results from malignant proliferation of plasma cells secreting a lot of monoclonal Ig (M proteins) of any given isotype

Front 120

What is special about IgA?

Back 120

It has a secretory component that protects it from enzymatic digestion at mucosal surfaces

Front 121

Where are CDRs found?

Back 121

Within the variable regions of both H & L chains

Front 122

True or false:
Each B cell produces Ig of a single Ag specificity

Back 122

True

Front 123

True or false:
Ab are capable of binding diverse configurations of epitope

Back 123

True

Front 124

What is the first step in B cell activation?

Back 124

Cross-linking of BcR with epitopes.

Front 125

What does 'capping' of sIgM BcR do?

Back 125

Sends a message to the co-receptors Ig-alpha and Ig-beta and initiates intracellular signaling pthwys

Front 126

How many subisotypes does IgG have?

Back 126

4... Predominant is IgG1

Front 127

True or false:
The variable regions of the paratopes don't differ for each subisotype of IgG

Back 127

True

Front 128

Which Ig is the only capable of crossing the placenta and how does it accomplish that?

Back 128

IgG... crosses via the Fc region on a protection receptor FcRn

Front 129

What is FcRn similar to?

Back 129

MHC Class I

Front 130

How many FcRn are needed to transport an IgG molecule?

Back 130

2

Front 131

IgG: Half-life...?
how is it recirculated?

Back 131

~23 days

re-circulated via an endosomal FcRN receptor (FcRP)

Front 132

Which Ig is capable of agglutination as well as precipitation?

Back 132

IgG

Front 133

How does IgG participate in opsonization?

Back 133

IgG binds Ag and facilitates phagocytosis via the Fc binding to receptors on PMNs and others

Front 134

When an Ab Fc binds to NK cell

Back 134

Antibody-dependent cell-mediated cytotoxic cell----- ADCC

Front 135

Major functions of IgG

Back 135

Activates Compliment
Neutralizes
Immobilizes
Opsonization

Front 136

Serum concentration upper limit IgG

Back 136

1600

Front 137

Number of subisotypes for IgA

Back 137

2: IgA1 IgA2

Front 138

What is the importance of IgA

Back 138

Important in the primary immunologic defenses of the GI and respiratory tracts *MALT*

Front 139

IgA in serum is a...?

in secretions...?

Back 139

Serum as a monomer

Secretions as a dimer

Front 140

How, where, and when is IgA2 dimer joined?

Back 140

by cystein-rich J chain intra-cellularly before secretion

Front 141

True of false:
IgA complement

Back 141

False!

Front 142

True or false:
IgG is an efficient antiviral antibody

Back 142

False: IgA is!

Front 143

What is the importance of secretory dimeric IgA?

Back 143

Important defense in mucous secretions

Front 144

How is IgA stabilized against proteolysis?

Back 144

By combination with a Secretory Component synthesized by local epithelial cells

Front 145

The secretory component that stabilizes IgA is a portion of...?

Back 145

the Poly-Ig receptor that mediates the transport of the dimer to the luminal surface.

Front 146

Secretory IgA upper limit concentration

Back 146

400

Front 147

Which Ig is Pentameric?

Back 147

IgM

Front 148

Which Igs have an extra heavy chain?

Back 148

IgM and IgE (CH4)

Front 149

How many epitopes can IgM theoretically bind?

Back 149

10

Front 150

How are Fc chains in IgM joined?

Back 150

disulfide bonds and a j chain

Front 151

IgM naturally occur against what?

Back 151

They are natural isohemagglutinin Ab that naturally occur against RBC Ag of the ABO blood groups

Front 152

What is the first isotype to be synthesized after Ag exposure?

Back 152

IgM

Front 153

What do elevated levels of IgM indicate?

Serum upper limit

Back 153

recent infection

200

Front 154

Which Ig is uniquely susceptible to proteolytic degradation?

Back 154

IgD

Front 155

Which Ig is the allergy Ab?

Aka...?

Back 155

IgE

cytotrophic or reaginic Ab

Front 156

What cells do IgE attach to and what is it responsible for?

Back 156

Binds via Fc region to mast cells and basophils and is responsible for immediate hypersensitivity and allergies... Also protects against worms (Helmiths)

Front 157

What denotes an Ig Superfamily?

Back 157

molecules found on cell surfaces with polypeptide chains with folded regions or domains (similar to Ab)

Front 158

Name the 4 phases in Primary Humoral Response

Back 158

1) Lag Phase (1-2 weeks)
2) Exponential Phase (rapid increase)
3) Steady Phase (production/degradation balanced)
4) Decline Phase (shut down)

Front 159

Describe the Booster/Anamnestic response

Back 159

2nd exposure to same Ag triggers memory B cells... shorter lag phase... IgM still first but higer longer [IgG]

Front 160

Which 2 Ab can fix or bind complement?

How many of each is needed?

Back 160

IgG (2 needed)

IgM (1)