Lec 1 - intro

Question 1

List the major cells involved in the innate and adaptive immune response

Describe the main functions of the innate immune system

Describe the process of phagocytosis and intracellular killing

Describe the basic role of Eosinophils and Mast cells

Describe the role of cytokines as chemical messengers within the immune system

Briefly describe the complement system and its main functions

Answer 1

Describe the fundamental properties of an adaptive immune response

Define the primary and secondary lymphoid organs and their functions

Outline the structure and function of antibodies

Describe the role of B-Lymphocytes in immunity

Describe how antigen processing cells and T-lymphocytes interact

Describe the origin of T-Lymphocytes

Describe the role of Helper T-Lymphocytes and Cytotoxic T Lymphocytes in the immune response

Question 2

Cells of innate immune system

Answer 2

Macrophages (in tissue)
NK cells
Dendritic cells (in tissue)
Mast cells (in tissue)
Neutrophils, eosinophils, basophils, monocytes (in blood)

Question 3

How do innate immune cells in tissues (i.e. macrophages, mast cells, dendritic cells) recognise foreign pathogens?

What do they release once foreign pathogen is recognised

Answer 3

Pattern recognition receptors

Cytokines

Question 4

Function of cytokines

Answer 4

Vasodilation
Inflammatory response,
Increased vascular permeability (more leaky
Recruit other immune cells to site of injury

Question 5

Functions of innate immune system

Answer 5

Antigen presentation
Complement activation
Phagocytosis
Inflammation
Recruit immune cells
Opsonisation
NK cytotoxicity

Question 6

Describe the process of phagocytosis and intracellular killing

Answer 6

When the phagocyte encounters the bacterium, it engulfs it and takes it into a small vesicle called a phagosome

This phagosome is then taken inside the cell where it fuses with another vesicle called a lysosome. The lysosome is full of digestive enzymes that kill the bacterium

Question 7

Other function of macrophages and dendritic cells apart from phagocytosis

Answer 7

Antigen presenting cells to T cells via MHC class I & II

Question 8

General difference between MHC class I & II

Answer 8

MHC class I - present on all nucleated cells and present INTRACELLULAR foreign antigens

MHC class II - found only on professional APCs (dendritic cells, macrophages, B cells) and present EXTRACELLULAR foreign antigens

Question 9

MHC class I presents to which subtype of T cell

MHC class II presents to which subtype of T cell

Answer 9

CD8

CD4

Question 10

Functions of the complement system (enzyme cascade that’s activated to help immune response)

Answer 10

Chemotaxis of phagocytes to sites of inflammation

Opsonisation - tagging of a microbe so it can be phagocytosed quicker

Lysis of micro-organisms

Maintenance of solubility of Ag/Ab

Question 11

Dendritic cells present antigens via which MCH class (think about definition of dendritic cell)

Answer 11

MCH class II - since dendritic cell is a PROFESSIONAL APC

Question 12

Examples of phagocytes (4)

Answer 12

Macrophages
Dendritic cells
Monocytes - LARGEST PHAGOCYTE
Neutrophils

Question 13

Cells of the adaptive immune system

Answer 13

T lymphocytes
B lymphocytes
Plasma cells (differentiated B lymphocyte)

Question 14

Where are both lymphocytes produced and where do they then mature

Answer 14

Bone marrow

T cells - mature in thymus
B cells - mature in bone marrow

Question 15

After B and T cells have matured, where do they go?

Answer 15

Move to secondary lymphoid organs (e.g. lymph nodes) where they encounter antigens and differentiate into more specific subtypes

Question 16

T helper cells produce cytokines which help to do what

Answer 16

Activate + recruit other immune cells

Question 17

CD8 (cytotoxic) T cells kill cells by what process

Answer 17

Inducing apoptosis of the target cell by releasing cytokines which apoptosis

Question 18

What type of T cells suppress excessive immune response

Answer 18

Regulatory T cells

Question 19

Actions of T helper cells

Answer 19

Activate macrophages
Induce inflammation
Activate (proliferate + differentiate) other T and B cells

Question 20

How do natural killer cells kill pathogens

Answer 20

NK cell releases perforin and granzyme - perforin creates a pore in the cell membrane of the pathogen and granzyme enters the cell to trigger apoptosis (PERFORIN INDUCED APOPTOSIS)

Question 21

Antibodies are produced by the activation of B lymphocytes by antigens and other signals

Antibodies of different heavy chain classes (isotypes) [i.e. IgG, IgM etc) perform different effector functions

List some functions of antibodies

Answer 21

Neutralise microbes and toxins by binding to antigens via its Fab region

Opsonise + phagocytose microbes

Antibody dependent cytotoxicity via NK cells

Activate complement

Question 22

In initial infection, which Ig is produced first

When the same antigen is encountered again, memory B cells accelerate response by doing what

Answer 22

IgM

Proliferating and differentiating into plasma cells –> fast high release of IgG specific to the antigen

Question 23

Physical + chemical barriers of immune system

Answer 23

• Skin
• Mucociliary escalator
• Acidic pH in stomach
• Rapid pH change in duodenum + alkaline pH in jejunum & ileum
• Lysozymes in tears, saliva, sweat
• Normal flora in bowel, vagina and on skin
• Flushing of urinary tract