Adaptive Immunity 1

Question 1

What adaptive immune response consists of?

Answer 1

Cell-mediated responses and antibody responses

Question 2

What is the role of T cells in adaptive immunity??

Answer 2

T cells drive cell-mediated immunity, it involves the activation of macrophages, natural killer (NK) cells.
* B cells produce antibodies driving humoral
immunity

Question 3

What is the role of B cells in adaptive immunity??

Answer 3

B cells produce antibodies driving humoral
immunity

Question 4

What is immunological memory?

Answer 4

Each pathogen remembered by a signature T cells and/ or B cell receptor

Question 5

What are the three main receptors in adaptive immunity?

Answer 5

-T cell Receptor
-B cell Receptor
-Major Histocompatibility Complex (MHC)

Question 6

Where T cells derived from and mature in?

Answer 6

They are derived from the bone marrow they mature in the Thymus (hence the ‘T’)

Question 7

What cells give rise to cellular immunity?

Answer 7

T cells

Question 8

Name different subset of T cells?

Answer 8

• T helper cells (CD4+) function to help support other immune cells to fight threats
• Cytotoxic T cells (CD8+) destroy our own cells which have become infected (usually virus-related)
• Regulatory T cells (Tregs): regulate or suppress other cells in the immune system

Question 9

Mention T cell receptors

Answer 9

Question 10

The T cells receptors are comprised of

Answer 10

• Constant region
• Variable region

Question 11

Three genetic segments confer diversity to variable region:

Answer 11

• (V) Variable - (Alpha and Beta chains)
• (D) Diversity - (Beta chains only)
• (J) Joining - (Alpha and Beta chains)

Question 12

What are the classes of T cell receptors:

Answer 12

• Alpha & Beta chains - Majority of T cells have this configuration
• Delta & Gamma chains - 5% of T cell population - role unknown

Question 13

Pre-thymic T cells educated in Thymus via two types of selection:

Answer 13

• Positive selection - No recognition → Induced apoptosis
• Negative selection - Recognition of self antigen → Induced apoptosis

Question 14

Process of thymic education is facilitated by interactions with?

Answer 14

T cell interact with Thymic cortical epithelial cells

Question 15

What type of immunity provides immunological memory?

Answer 15

Adaptive immunity

Question 16

How genes are re-arranged ?

Answer 16

Somatic recombination

Question 17

Hoe T cells get activated?

Answer 17

From antigen presentation by DCs

Question 18

Where T cells priming occurs and what it results?

Answer 18

In the lymph nodes and results in differentiation into subsets

Question 19

T cell priming

Answer 19

1. Signal 1 - Recognition of antigen presented by MHC on dendritic cells: T cells recognize antigen presented by dendritic cells via T cell receptor (TCR) binding to the antigen-MHC complex.
   ( naïve T cell activation (MHC-TCR) )
2. Signal 2 - Co-stimulation: T cells require a second signal to become fully activated, which is delivered by co-stimulatory molecules on dendritic cells, such as CD80 and CD86, binding to CD28 on T cells.
   ( preventing T cell anergy )
3. Signal 3 - Cytokine stimulation: T cells receive cytokine stimulation from dendritic cells, which helps determine their initial differentiation into effector or memory cells.
   ( cytokine response drives differentiation )

Question 20

TH2 cells roles?

Answer 20

-Main role in supporting humoral responses and allergic reactions
-Source of cytokines such as interleukin-4, 5 and 6 (IL-4, IL-5 and IL-6) which instruct B cells to produce antibodies

Question 21

Regulatory T cells roles?

Answer 21

Main role is to function in immune suppression by releasing inhibitory cytokines (e.g., interleukin-10,[IL-10]) which
inhibit T cell and DCs activation

Question 22

Cytotoxic T cells roles?

Answer 22

Activation arises from interactions between MHCI and TCR
Induce host cells to undergo apoptosis (programmed cell death)
Produces enzymes such as granzyme/ perforin

Question 23

What granzyme/perforin does when they produced?

Answer 23

-Perforins: form pores in the plasma membrane
-Granzymes: enter the cell and break down proteins, lysing the cells