Exam 3 - Immunology (AI Flashcards)

Question 1

What is the function of the mammalian immune system?

Answer 1

To differentiate between self and non-self and protect the organism

This involves an integrated network of cells and their products.

Question 2

What are the primary components of the immune system?

Answer 2

Innate and Adaptive (Acquired) immunity

Innate is present in most eukaryotic life forms; Adaptive exists only in vertebrates.

Question 3

What is the innate immune system?

Answer 3

An ancient system present in most eukaryotic life forms that exists pre-infection and exhibits broad specificities

It is the early response to infection.

Question 4

What is the adaptive immune system?

Answer 4

A system that matures on exposure to antigens and is remembered (anamnestic response)

Exists only in vertebrates.

Question 5

What is hematopoiesis?

Answer 5

The production of blood cells in the bone marrow

It includes the formation of myeloid and lymphoid cells.

Question 6

Where does maturation of B cells occur?

Answer 6

In the bone marrow

For birds, it occurs in the Bursa of Fabricius.

Question 7

Where does maturation of T cells occur?

Answer 7

In the thymus

Maturation starts in the outer cortex and continues towards the medulla.

Question 8

What percentage of thymocytes survive the maturation process?

Answer 8

Less than 5%

95% do not make it out alive.

Question 9

What are the classes of lymphocytes involved in adaptive immune responses?

Answer 9

There are multiple classes of lymphocytes

Specific classes include T cells and B cells.

Question 10

Where do immune responses primarily occur?

Answer 10

In lymph nodes, spleen, cutaneous immune system, and mucosal immune system

Mucosal immune system includes the gut, tonsils, appendix, lungs, and mucus membranes.

Question 11

What is the major site of immune responses to blood-borne antigens?

Answer 11

The spleen

It has red pulp for destroying old red blood cells and white pulp for immune responses.

Question 12

What is passive immunity?

Answer 12

The transfer of antibodies or lymphocytes to a naïve animal

This can occur after an active immune response.

Question 13

What are the stages of an adaptive immune response?

Answer 13

Recognition, activation and proliferation, differentiation, effector functions, and memory

Homeostasis is also part of the immune response process.

Question 14

Fill in the blank: The _______ immune system is responsible for the immune responses in the skin.

Answer 14

cutaneous

It interacts with the external environment.

Question 15

True or False: The adaptive immune system is present in both eukaryotic and prokaryotic life forms.

Answer 15

False

The adaptive immune system exists only in vertebrates.

Question 16

What does the term ‘anamnestic’ refer to in the context of the immune system?

Answer 16

The ability of the immune system to remember past infections

This is a key feature of the adaptive immune response.

Question 17

What is the role of chemical messengers in the immune system?

Answer 17

They facilitate communication between immune cells

This coordination is essential for an effective immune response.

Question 18

What is immunogenicity?

Answer 18

The ability of a given molecule to induce an immune response

Some molecules are inert, some are poor and some are good.

Question 19

List general characteristics that contribute to immunogenicity

Answer 19

• Phylogenetic foreignness
• Chemical nature (protein vs CHO vs lipid)
• Size
• Complexity
• Route of uptake
• Host

Question 20

Define antigen (Ag)

Answer 20

A molecule that binds specifically with an antibody (Ab) or T cell receptor

Question 21

Define epitope

Answer 21

The actual part of an antigen that binds to an Ab or T cell receptor binding site

Question 22

What are multivalent antigens?

Answer 22

Antigens that have multiple epitopes

Question 23

What types of epitopes exist?

Answer 23

• Repeated within the Ag molecule
• Not repeated within the Ag molecule
• Overlapping
• Formed by linear arrays of AAs
• Conformational (AAs not in a sequence)
• Neo-epitopes (exist/exposed after Ag changes such as phosphorylation, proteolysis)

Question 24

What is an antibody (Ab)?

Answer 24

A family of millions of structurally related glycoproteins

Question 25

How are antibodies produced?

Answer 25

By B lymphocytes/Plasma cells

Question 26

What are the two broad forms of antibodies?

Answer 26

* Bound to B cell membranes (acting as B cell receptors for antigens) * Secreted soluble form (free floating and able to bind Ag in plasma, mucosal secretions, interstitial fluids)

Question 27

What can antibodies do when they bind to Ags?

Answer 27

* Remove the Ag – precipitate it out or induce phagocytosis * Neutralize the Ag – prevent a microbial enzyme from working or a virus from binding * Kill organism expressing the Ag – pokes holes in them * Trigger hypersensitivity reactions – histamine release, immune complex activation of complement proteins

Question 28

Describe the basic structure of an antibody

Answer 28

Two symmetrical branches each made up of 2 identical light chains (L) and 2 identical heavy chains (H)

Question 29

What connects the light chains and heavy chains in an antibody?

Answer 29

One L chain is covalently attached to one H chain by S-S bonds, and the other two H chains are attached to each other by S-S bonds

Question 30

What are variable regions in antibodies?

Answer 30

Regions that recognize epitopes and make the Ab combining site

Question 31

What are complementarity determining regions (CDRs)?

Answer 31

Hypervariable regions on the N-terminal Ig domain of each L and H chain that are complementary to the epitope

Question 32

What is the role of C regions in antibodies?

Answer 32

They mediate most of the biological functions of the antibody and determine the isotype (or class) of the Ig

Question 33

True or False: Constant regions interact with the antigen/epitope.

Answer 33

False

Question 34

What determines the isotype (or class) of the immunoglobulin?

Answer 34

The C regions of the heavy chains

Question 35

List the different isotypes of immunoglobulin.

Answer 35

Different isotypes are selectively distributed in the body ## Footnote Specific isotypes were not detailed in the provided text.

Question 36

What are H chains denoted by?

Answer 36

Greek letters

Question 37

How are H chain C regions numbered?

Answer 37

CH1, CH2, etc., numbering from the NH2 terminus

Question 38

What is the purpose of the hinge region in H chains?

Answer 38

Allows flex (molecular motion) and varies in length across isotypes

Question 39

What is the length range of the hinge region in H chains?

Answer 39

10-60 AAs

Question 40

What forms can antibodies (Abs) be expressed in?

Answer 40

Secreted or membrane forms

Question 41

Where is the membrane form of Abs found?

Answer 41

On B cells that produce that specific Ab

Question 42

What differentiates membrane and secreted forms of Ig?

Answer 42

Differences in AA sequence at the COOH terminus of the H chain C region

Question 43

What are transmembrane regions made up of?

Answer 43

Hydrophobic AAs

Question 44

What type of forms are the secreted forms of IgG and IgE?

Answer 44

Monomeric

Question 45

What type of forms are the secreted forms of IgA and IgM?

Answer 45

Covalently bound multimers

Question 46

What is the role of the J piece in IgM and IgA?

Answer 46

Stabilization through S-S bonding to tail pieces

Question 47

What are the characteristics of antibodies (Abs)?

Answer 47

* At least bi-valent * Flexible * Membrane form is the B cell receptor * Secreted form acts throughout the body * V Regions combine with Ag in a highly specific manner * C Regions interact with multiple cell types and soluble inflammatory molecules

Question 48

What is the difference between monoclonal and polyclonal Abs?

Answer 48

Monoclonal Abs are made by a single B cell clone; polyclonal Abs are from multiple B cells

Question 49

What is affinity maturation?

Answer 49

A process that yields Abs that bind tightly to their Ag through somatic mutations in Ag-stimulated B cells

Question 50

What happens to B cells with higher affinity receptors during affinity maturation?

Answer 50

They are further selected by Ag and become the most dominant

Question 51

What is the definition of antibody affinity?

Answer 51

The measure of the on/off rate between Ag and Ab combining site

Question 52

What does avidity refer to in the context of antibodies?

Answer 52

The overall strength of attachment of an Ab to its Ag

Question 53

What is the relationship between affinity, valency, and avidity?

Answer 53

Avidity = Affinity + Valency

Question 54

What are common assays that use Abs?

Answer 54

* Enzyme-linked immunoabsorbant assays (ELISA) * Radioimmunoassays (RIAs) * Hemagglutination Assays (HAs) * Flow Cytometry * Immunohistochemistry * Western Blot assays * Dipstick Assays

Question 55

What is the purpose of an ELISA setup?

Answer 55

To quantify the concentration of Ag

Question 56

What are key terminologies related to antibodies?

Answer 56

* Immunogen * Antigen * Epitope * Ab structure: H & L chains, V & C Regions (CDRs) * Membrane and secreted forms * Monoclonal vs. Polyclonal Abs * Ab specificity (cross reactions) * Ab/Ag reactions * Ab Assays (ELISA)