L3 (overview lecture)

Question 1

How do the timing and speed of response differ between the innate and adaptive immune systems?

Answer 1

Innate: Fast, immediate response.

Adaptive: Slower to develop (5–6+ days).

Question 2

How do the innate and adaptive immune systems detect pathogens?

Answer 2

Innate: Uses germline-encoded, limited, unchanging receptors.

Adaptive: Uses randomly generated antigen receptors with huge diversity and specificity to individual molecules.

Question 3

What is the specificity of the immune response in the innate versus adaptive systems?

Answer 3

Innate: Nonspecific, recognizes broad patterns of pathogens.

Adaptive: Highly specific to individual molecules (antigens).

Question 4

What are the key cell types involved in the innate and adaptive immune systems?

Answer 4

Innate: Phagocytic cells (macrophages, neutrophils, dendritic cells).

Adaptive: Lymphocytes (B and T cells).

Question 5

How do the innate and adaptive immune systems respond to repeat infections?

Answer 5

Innate: Response is the same each time.

Adaptive: Response is faster and more effective with each subsequent exposure (memory).

Question 6

What are the major components of the innate and adaptive immune systems

Answer 6

Innate: Barriers (e.g., skin), phagocytes, pattern recognition molecules.

Adaptive: T and B lymphocytes, antigen-specific receptors, antibodies.

Question 7

What are the key takeaways about the phases of the immune response?

Answer 7

Many phases to the immune response.
Takes time to develop.

Question 8

How long does the innate immune response last, and how fast is it?

Answer 8

The innate immune response is fast and only lasts for days.

Question 9

What is the role of pattern recognition receptors (PRRs) in the immune system?

Answer 9

PRRs provide an initial discrimination between self and non-self by recognizing broad categories of molecules commonly found in pathogens (PAMPs).

Question 10

What are pathogen-associated molecular patterns (PAMPs)?

Answer 10

PAMPs are common foreign structures that characterize whole groups of pathogens. They are present in many microorganisms but not in the host body’s own cells.

Question 11

Which receptors are involved in recognizing PAMPs?

Answer 11

Toll-like receptors (TLRs) are a type of PRR involved in recognizing PAMPs.

Question 12

How do macrophages recognize different pathogens?

Answer 12

Macrophages express several receptors, including PRRs, that allow them to recognize different pathogens.

Question 13

What happens when PRRs on innate immune cells, like macrophages, are activated?

Answer 13

Activation of PRRs can directly induce effector functions in these cells, such as phagocytosis.

Question 14

How do innate immune cells amplify the immune response?

Answer 14

By producing inflammatory mediators, including cytokines and chemokines.

Question 15

What are the roles of cytokines and chemokines in the immune response?

Answer 15

Cytokines: Signal other immune cells to enhance the immune response.

Chemokines: Attract immune cells to the site of infection or injury.

Question 16

What triggers an inflammatory response during infection?

Answer 16

Cells produce mediators like chemokines and cytokines.

Question 17

What are the mediators of inflammation, and what do they do?

Answer 17

Chemokines: Attract immune cells to the site of infection.

Cytokines: Signal and regulate the immune response.

Question 18

What are the four hallmarks of inflammation?

Answer 18

Redness, heat, swelling, and pain.

Question 19

How do dendritic cells link the innate and adaptive immune systems?

Answer 19

Dendritic cells travel from the site of infection to local secondary lymphoid tissue, where they interact with and activate T cells.

Question 20

Where do dendritic cells activate T cells?

Answer 20

In secondary lymphoid tissue.

Question 21

Where does T and B cell activation occur?

Answer 21

In the peripheral lymphoid tissue, specifically the lymph nodes.

Question 22

How are T cells activated?

Answer 22

T cells are activated by antigen-presenting cells (APCs) through three crucial signals.

Question 23

What are the three signals required for T cell activation?

Answer 23

1) Interaction of specific molecules (e.g., receptors).

2) Cytokine signaling.

3) Additional co-stimulatory signals (details can be added later as needed).

Question 24

What is an epitope, and how is it related to an antigen?

Answer 24

An epitope is a specific part of an antigen, which can be a piece of peptide buried within a protein.

Question 25

How is an antigen or epitope presented to T cells?

Answer 25

The antigen/epitope is presented using a Major Histocompatibility Complex (MHC), which interacts with the T cell receptor (TCR).

Question 26

Where does the activation of antigen-specific adaptive immune cells occur?

Answer 26

In secondary lymphoid tissues, such as lymph nodes.

Question 27

Which cells are activated during adaptive immunity?

Answer 27

T cells and B cells.

Question 28

How is antigen specificity determined in T and B cells?

Answer 28

1) T cells: By their T cell receptor (TCR). 2) B cells: By their B cell receptor (BCR), which is also known as an antibody or immunoglobulin.

Question 29

What are antibodies (Abs), and how are they produced?

Answer 29

Antibodies are secreted immunoglobulin (Ig) molecules made by B lymphocytes and their progeny plasma cells.

Question 30

What is the primary function of antibodies?

Answer 30

Antibodies bind to antigens (Ag).

Question 31

Where are antibodies found in the body?

Answer 31

Antibodies circulate in the serum, the fluid component of blood.

Question 32

Can two antibodies recognize different epitopes on the same antigen?

Answer 32

Yes, two antibodies can recognize different epitopes on the same antigen.

Question 33

Where do B cells and T cells arise and mature?

Answer 33

1) B cells: Arise and mature in the bone marrow. 2) T cells: Arise from bone marrow progenitors but mature in the thymus.

Question 34

How do B cell receptors (BCRs) and T cell receptors (TCRs) differ in their form?

Answer 34

1) BCR: Can be membrane-bound or secreted as antibodies (Abs). 2) TCR: Exists only as a membrane-bound receptor.

Question 35

How do BCRs and TCRs recognize antigens?

Answer 35

1) BCR: Recognizes antigens in their natural form. 2) TCR: Recognizes small pieces of antigens bound to MHC molecules on the surface of Antigen-Presenting Cells (APCs).

Question 36

What is the origin of the diversity of lymphocyte specificity?

Answer 36

A single progenitor cell gives rise to a large number of lymphocytes, each with a different specificity for a distinct antigen.

Question 37

What is the specificity of BCRs and TCRs in individual B and T cells?

Answer 37

Each B and T cell has an individual specificity for a single antigen and expresses many identical copies of one receptor specific to that antigen.

Question 38

How is the diversity of antigen specificities among lymphocytes achieved?

Answer 38

Through the rearrangement and editing of genomic DNA that encodes antigen receptors in B and T cells.

Question 39

What is the theoretical potential of BCR and TCR specificity?

Answer 39

The immune system has a huge diversity of lymphocytes, providing the potential to respond to any antigen.

Question 40

What happens if a lymphocyte reacts to a self-antigen during development?

Answer 40

It is eliminated through clonal deletion, which removes potentially self-reactive immature lymphocytes.

Question 41

What happens during clonal selection in B or T cells?

Answer 41

When a B or T cell interacts with its specific antigen, it is selected and activated.

Question 42

What is the result of activation in clonal selection?

Answer 42

The activated lymphocyte proliferates, producing a large number of clones, each reactive against the original antigen

Question 43

What is the process of clonal selection in terms of lymphocyte activation?

Answer 43

Mature naive lymphocytes encounter a foreign antigen, leading to the proliferation and differentiation of activated lymphocytes into a clone of effector cells.

Question 44

What happens after T and B cells are activated in lymphoid organs?

Answer 44

They become effector cells capable of fighting infections.

Question 45

What is humoral immunity, and how does it combat pathogens?

Answer 45

Humoral immunity combats pathogens via antibodies.

Question 46

What is cell-mediated immunity, and which cells are involved?

Answer 46

Cell-mediated immunity involves primarily T lymphocytes.

Question 47

How do humoral and cell-mediated immunity work together?

Answer 47

Both humoral and cell-mediated activities contribute to the immune response to fight infections.

Question 48

How do T cells contribute to adaptive immunity?

Answer 48

T cells contribute to adaptive immunity in many ways, including activating other immune cells and killing infected cells.

Question 49

How do different T cell subsets function in cell-mediated immunity?

Answer 49

1) Some T cells help activate B cells. 2) Some T cells help activate macrophages. 3) Some T cells kill infected cells directly.

Question 50

How does humoral immunity contribute to adaptive immunity?

Answer 50

Humoral immunity contributes by producing specific antibodies that can clear and neutralize antigens.

Question 51

What are the types and functions of antibodies in humoral immunity?

Answer 51

There are different types of antibodies. Antibodies can act in various ways, including clearing and neutralizing antigens.

Question 52

What is the role of regulation and memory in immune responses?

Answer 52

Regulation involves downregulation of lymphocytes, and immunological memory helps the immune system respond faster to subsequent infections.

Question 53

What is the difference between active and passive immunization?

Answer 53

(1) Active Immunization: Induces an adaptive immune response. - Natural: Natural infection. - Induced: Vaccination. (2) Passive Immunization: Involves transfer of immunity through cells or molecules. - Natural: Transfer of antibodies from mother to fetus. - Induced: Monoclonal antibody therapy.